bluuebunny/crossref_metadata_2025 huggingface dataset:
Globalisation and Urban Transformations in the Asia-Pacific Region: A Review
Authors: Lo Fu-chen , Marcotullio Peter J.
Published: July 2002

In the Asia-Pacific context, over the past several decades, economic globalisation permitted the deepening of intrafirm trade, foreign direct investment and the division of labour between head offices and their subsidiaries abroad, thus effecting a greater interdependency between the developed nations and developing nations in the region. The linkages of this emerging transnational economy are embedded in the region's cities through the world city formation process and have led to the development of a 'functional city system'. Urban functions, within the system include, inter alia, production, finance, telecommunications, transportation, direct investment and even amenity provision. The accumulation of different functions by a given city provides for the foundation of its external linkage and economic growth and also underlies transformations in its physical form. While all cities have a variety of functions and play many roles within the regional economy, dominant characteristics found in cities allow for the identification of different types including capital export cities, regional entrepots, industrial cities and amenity cities.
Social Capital, Gentrification and Neighbourhood Change in London: A Comparison of Three South London Neighbourhoods
Authors: Butler Tim , Robson Garry
Published: July 2002

Social capital has been used extensively in recent years to examine issues of social exclusion. Following Bourdieu, the concept is reintegrated into social theory alongside cultural and economic capital to examine the variations in the upgrading of gentrified areas of inner London. Three neighbourhoods in south London are compared and it is argued that their differences can, to a limited extent, be understood in terms of the differential deployment of cultural, social and economic capital by their middle-class residents. These neighbourhoods have acquired distinctive characters as a result and it is argued that the gentrification process in inner London is leading to heterogeneous middle-class neighbourhoods which contrasts with the perceived homogeneity of the traditional suburban area.
Contemporary Deindustrialisation and Tertiarisation in the London Economy
Authors: Graham Daniel , Spence Nigel
Published: July 2002

This study provides an empirical examination of recent change in the London economy to assess the degree to which the processes of deindustrialisation and tertiarisation have affected the capital. Three different components of the London economy are considered-output, establishment structure and employment. It is demonstrated that each of these has changed in different ways and that this raises subtle questions as to how deindustrialisation and tertiarisation have affected London. In particular, it is shown that in both the service and manufacturing sectors substantial productivity gains have been made, and that the economic structure of the capital appears to be changing in a completely different way from that of the rest of the nation. Difficulties and inconsistencies clearly arise when using the concepts of deindustrialisation and tertiarisation to analyse economic change in London. Analysis based on the distinct nature of the economic activities located within the capital related to its specialist role as a global city would seem to offer greater analytical potential.
Globalisation, Territory and Strategic Alliances in Different Financial Centres
Authors: Budd Leslie
Published: July 2002

The debates about globalisation, global finance and global cities appear to confuse global and international changes and seem a-historical. This paper begins with a sceptical assessment of globalisation and asks whether a globalised economy is really an internationalised one. The paper then addresses an aspect of global finance—the national impetus given to alliances between markets in major cities. The financial derivatives markets, particularly in Europe, are used to exemplify this trend and to question the degree to which electronic trading poses a threat to the economic welfare of the urban territories in which they are located. In conclusion, the prospect of major players in large financial centres becoming incorporated into the governance of urban policy is raised.
What Has Happened to the Bottom of the US Housing Market?
Authors: Malpezzi Stephen , Green Richard K.
Published: July 2002

Housing quality has improved dramatically for most low-income households, but they are paying much larger shares of their income for it. Many discussions of the bottom of the market focus on either the rising costs (the 'bad' news) or the rising quality (the 'good' news). Both points of view have some merit. This paper takes a positivist approach to the question: what's happening to the bottom of the housing market. We use a variety of indicators to look at whether the supply of low-cost units has fallen. We then focus on whether this dwindling supply reflects a market failure. If the market for low-income housing is indeed failing, we would observe: relatively high prices per unit of housing services provided by low-quality housing; obstructions to the supply of low-cost housing, which arises largely from filtering; and high vacancy rates. We find evidence of market failure in some markets but not in others. Finally, we focus on one possible source of market failure—excessive regulation—to see whether it is a common thread across those markets that have difficulty producing low-cost housing.
Global Economic Change, Labour Market Adjustment and the Challenges for European Housing Policies
Authors: Maclennan Duncan , Pryce Gwilym
Published: July 2002

This paper examines the 'global competition' aspects of housing policies and the implications of an emerging 'flexible' economic order for housing markets in advanced economies. An overview is given of movements in international patterns of growth and trade, including a review of the effects on labour and housing markets of increased competition from less developed, and newly industrialised, countries. UK labour market experience is examined, along with the responses of, and implications for, housing systems and policies. Emphasis is placed on the need to understand the connections between global economic change and regional/local housing systems when designing housing policy. The paper underlines the importance of integrating housing strategies with national competition policy.
Childfare : A New Direction for Welfare Reform
Authors: Baratz Morton S. , White Sammis B.
Published: July 2002

In August 1996, President Clinton signed the Personal Responsibility and Work Opportunity Act, fulfilling his campaign promise to "end welfare as we know it". The legislation replaces the six-decade-old Aid To Families With Dependent Children programme (AFDC) with so-called workfare under which recipient parents may no longer receive financial assistance indefinitely. Instead, they must obtain employment or other means of support within two years, after which benefits are reduced or cease entirely. There is broad consensus that workfare is a step in the right direction. This paper challenges that consensus. The programme will intensify the plight of welfare children and deepen the economic problems of America in future years. We propose instead a programme that also promotes the work ethic as a basic premise of reform, but that seeks to reduce welfare rolls by making the education and development of assisted children the central obligation of AFDC parents.
Analysing the Politics of Local Economic Development: Making Sense of Cross-national Convergence
Authors: Wood Andrew
Published: July 2002

There are a number of recent trends in the organisation of local economic development activities that are seen to point to a general convergence between UK and US contexts. Various attempts have been made to encompass this convergence, primarily through the application of a set of common concepts such as the 'growth coalition' and 'urban regime'. This paper draws on a recently completed research project to highlight differences in the organisation of local economic development activities between the US and the UK. These differences are subsequently used to provide a critical window on existing theoretical frameworks and to elaborate on the concept of local dependence as a means of analysing and understanding the politics of local economic development in different contexts.
Infrastructure Provision, Development Processes and the Co-production of Environmental Value
Authors: Marvin Simon , Guy Simon
Published: July 2002

This paper argues that the current debate about developer contributions in relation to infrastructure networks is blinding us to radical shifts emerging in the relationship between infrastructure providers and developers. Moreover, we suggest that conventional planning discourse about infrastructure charges, standardised service fees and impact assessment could actually hamper the emergence of this new logic. The paper illustrates how a new logic of network provision is subtly, yet profoundly, shifting the context within which the bargaining process unfolds by highlighting the proactive role of infrastructure providers in shaping the location, form and specification of three new developments. We argue that if debate is not extended to take account of these new infrastructure practices then planners will miss a significant new opportunity for promoting new communities of interest between actors who have conventionally been seen as adversarial and thereby encouraging environmentally sensitive development activity that may provide wider community benefits.
Structure and Mayoral Roles: A Research Note
Authors: Thompson Edward , Brodsky David M.
Published: July 2002

The research on urban leadership attributes the performance of mayors either to institutional factors or to individual characteristics. Taking advantage of a 'natural experiment', we assess the effects of a change from a commission to a mayor-council government on an individual who served as mayor in both. Using data from personal interviews, we compare the roles attributed to the incumbent and find the roles emphasised shifted with the change in structure. We also found that the mayor's leadership style did not change, suggesting that the change in structure accounts for the differences in reported activities.
Law, Legal Struggles and Urban Regeneration: Rethinking the Relationships
Authors: Imrie Rob , Thomas Huw
Published: July 2002

The interrelationships between law, legal processes and urban regeneration have been little addressed by researchers of urban studies, while few have acknowledged the centrality of law as one of the core facets involved in the restructuring of the built environment. Rather, it has tended to be taken as 'given', as an underpinning of socio-institutional actions rather than being conceptualised as constitutive of them. In seeking to redress this imbalance, the paper considers the role of legal processes in urban regeneration through an exploration of the multiple and contested terrains of one of the core tools of urban regeneration, the compulsory purchase order (CPO). In exploring the interplay between urban renewal and CPOs, the paper begins by providing a brief overview and critique of the claimed value-neutrality of the Anglo-American tradition of law and legal processes, while outlining alternative ways of conceiving of the multiple interrelationships between law and socio-spatial processes. In a second section, we deploy case-study material to illustrate and discuss the socio-legal processes underpinning the CPO. We develop the argument, following Chouinard, that the legal discourses, practices and institutions of CPOs are powerful factors in perpetuating relations of social authority, power, exclusion and oppression.
What is a Central City in the United States? Applying a Statistical Technique for Developing Taxonomies
Authors: Hill Edward W. , Brennan John F. , Wolman Harold L.
Published: July 2002

We test the null hypothesis that municipalities defined as central cities by the US Bureau of the Census in 1990 are homogeneous-a hypothesis we reject. Rather, we find that US central cities consist of 2 distinct subsets of municipalities that are aggregated from 13 cluster groupings. The article has two purposes. The first is methodological. We develop a method that uses cluster analysis to group US central cities; then we employ discriminant analysis to establish the statistical validity of those groups. We also develop techniques to minimise the role of judgement in selecting the appropriate cluster solution. The second purpose of the article is to test the substantive null hypothesis. Our rejection of the homogeneity assumption raises the spectre of specification error in research and public policies that assume homogeneity among central cities.
Poverty and Urban Public Expenditures
Authors: Pack Janet Rothenberg
Published: July 2002

Cities in the US bear a disproportionate responsibility for the public expenditures that grow out of poverty because they contain disproportionate numbers of the poor and because a substantial part of the public expenditures associated with poverty are financed from local resources. The research reported here estimates how large these poverty-related expenditures are and how the fiscal burdens differ for the populations of cities with high and low poverty rates. A major finding is that the largest poverty-related expenditure burdens come from indirect poverty expenditures-additional expenditures on police, fire, courts, general administrative functions-rather than from primary poverty functions like public welfare, health and hospitals.
Predicting the Growth and Filtering of At-risk Housing: Structure Ageing, Poverty and Redlining
Authors: Margulis Harry L.
Published: July 2002

Using canonical regression analysis, the paper examines the associations between housing conditions, race, poverty and vintage structure age in Cleveland, Ohio's east and west sides. It is found that African-Americans are concentrated in the oldest at-risk housing stocks on Cleveland's east side, but chronic poverty rather than quality deficiency is most associated with their presence. On the west side, the oldest housing stock is experiencing the most deterioration, but a linkage between race and at-risk vintage units is not established; rather, chronic poverty is directly associated with age depreciation. Lastly, in examining the effects of housing conditions, race and mortgage lending, it is found that credit access has little to do with race; rather, housing conditions and the age-depreciation process most affect credit receipt and operate independently of race.
Community Agency in the New South Africa: A Comparative Approach
Authors: Lyons Michal , Smuts Carin
Published: July 2002

Using South Africa as a case study for the workings of community agency in partnerships with the public and non-profit sector, this paper focuses on community-driven developments in townships in the Western Cape. The hypothesis is put forward that although structural factors are a major influence on the success of community agency, a formal approach to project management offers a powerful tool for mitigating their impact. The paper addresses the strengths of formal project structure in the development process, and considers its limitations. Five development projects in townships in the Western Cape are examined for preliminary evidence on this hypothesis and broader implications for the nature of participative democratic process are discussed.
The Fiscal Role of the European Union: The Case of Housing and the European Structural Funds
Authors: Stephens Mark
Published: July 2002

This paper examines the potential for the European budget to be used to contribute to housing investment. It finds that the budget is sufficiently large to play a role in the countries where the budget is concentrated, although it could be made more progressive. Case studies reveal that the current 'allocative' purpose of the Structural Funds, combined with a misinterpretation of 'subsidiarity', largely prevents their use for housing investment. Together with the principle of 'additionality', the current budget rules are shown to have the potential to cause 'welfare waste', which could be relieved either by moving to a wholly redistributive budget or by amending existing rules to allow funds to be used for housing investment when this contributes to economic regeneration.
Stressful family environment, mortality, and child socialisation: Life-history strategies among adolescents and adults from unfavourable social circumstances
Authors: Bereczkei Tamas , Csanaky Andras
Published: July 2002

This study, based on questionnaires given to 732 subjects, uses an integrative approach with a focus on evolutionary (life-history) explanations. In accordance with Belsky, Steinberg, and Draper’s theoretical model of socialisation (1991), we claim that experiences during childhood trigger variations in the life cycle and shift developmental trajectories as adaptive answers to different environmental conditions. Unfavourable family conditions constitute an unpredictable and unstable environment that make children susceptible to adopting opportunistic mating strategies rather than parenting strategies. Based on Chisholm’s statement (1993) that high stress in the family provides cues for local death rates, we argue that mortality rates may have a significant effect on reproductive decisions, even in post-industrial societies. We report that length of schooling, date of the ” rst marriage, and fertility were associated with the subjects’ family conditions, such as parental affirmation, emotional atmosphere, parent-subject conflicts, and parental relations. Women growing up in unfavourable family circumstances ”nish schooling and marry earlier, and this shift in developmental trajectory is likely to lead to the higher number of children measured among these women. Men, on the other hand, do not show such a difference in reproductive output, which may be due to their increased involvement in sexual competition. Remarkably, significant correlation has been found between life-history strategy and mortality rates; those coming from unfavourable environments have more deceased sisters and brothers than others. It is possible that individual differences in mating and parenting behaviour are still contingent, among others, on local death rates.
A Developmental Guide to the Organisation of Close Relationships
Authors: Laursen Brett , Bukowski William M.
Published: July 2002

A developmental guide to close relationships is presented. Parent-child, sibling, friend, and romantic relationships are described along dimensions that address permanence, power, and gender. These dimensions describe relationship differences in organisational principles that encompass internal representations, social understanding, and interpersonal experiences. The concept of domain specificity is borrowed from cognitive development to address the shifting developmental dynamics of close relationships. Distinct relationships are organised around distinct socialisation tasks, so each relationship requires its own organisational system. As a consequence, different principles guide different relationships, and these organisational principles change with development.
Getting through Grade 2: Predicting Children’s Early School Achievement in Rural South African Schools
Authors: Liddell Christine , Lycett John , Rae Gordon
Published: July 2002

Children in the second-grade classrooms of three rural schools ( n 150) completed a variety of psychometric and curriculum-based tests, and were rated by their teachers and parents on dimensions of their everyday behaviour; demographic data (e.g. socioeconomic status, presence of mother in the home) and biographical information (e.g. gender, age, birth order) were also collected for each child. Some of these data (e.g. child’s age and gender) were more cost-efficient to collect than others (e.g. parent ratings). Measures were evaluated in terms of their salience for constructing a multivariate model that would predict subsequent grade 2 outcome, with the most cost-effective variables being inserted first. In this way, both the cost-efficiency and predictive power of independent variables (IVs) were taken into consideration when attempting to build a predictive model. A model containing three IVs (scores on curriculum-based tests, teacher ratings of children’s attention span, and teacher ratings of helpfulness) ultimately predicted 51% of the variance in grade 2 outcome. These results demonstrate, first, that it is possible to build a relatively strong predictive model of grade 2 outcome, although not based on variables that are cheap and quick to measure. Second, that doing well in grade 2 is not so much a matter of having well-developed, broad-ranging psychometric abilities, but more a matter of mastering elements of the curriculum and behaving in ways that permit adaptation to the requirements of crowded and under-resourced African classrooms.
The international drug control system in the post‐Cold War era. Managing markets or fighting a war?
Authors: Room Robin , Paglia Angela
Published: July 2002

The core institutions and scope of the international drug control system are described. The system has grown in participation and particularly in scope and ambitions since it was studied in the early 1970s by Bruun and colleagues. Its premises are notably in conflict with the currently dominant ideologies of a free‐market global economy although, as earlier, the United States plays a dominant role in the drug control system. At a time when it is seen as a failure in its primary aims both from inside and from outside, defenses of the system have ranged from rousing rhetorical appeals to efforts to “de‐sensationalize” the issues.
Feasibility of Matching Alcohol Patients to ASAM Levels of Care
Authors: Kosanke Nicole , Magura Stephen , Staines Graham , Foote Jeffrey , DeLuca Alexander
Published: July 2002

The study examined the feasibility of implementing treatment recommendations derived from the American Society of Addiction Medicine (ASAM) Patient Placement Criteria in an urban addiction treatment program that offered a continuum of levels of care (LOC). A cohort of 281 applicants for alcoholism treatment were evaluated and the reasons for observed differences (“mismatches”) between recommended and actual LOC placements were determined. Overall, 88% of the applicants entered treatment, and 72% of these were matched to LOC vs. 28% who were mismatched. Presumptive overtreatment (59%) was more common than undertreatment (41 %) among the mismatched patients. The reasons for overtreatment were availability of Medicaid coverage for inpatient rehabilitation (93%), referral sources' treatment philosophy of gradually “stepping down” from inpatient detoxification (59%), social pressures on patients (28%), and mandated treatment (8%). The reasons for presumptive undertreatment were work schedule conflicts (72%), patient reluctance (48%), insurance coverage (15%), and interference with family or personal responsibilities (9%). These results indicate multiple barriers that need to be overcome to enable full implementation of the ASAM Criteria in real world program settings, even when a continuum of care is available.
Mitochondria in the Programmed Death Phenomena; A Principle of Biology: “It Is Better to Die than to be Wrong”
Authors: Skulachev Vladimir P.
Published: July 2002

The very fact that mitochondria participate in amplification of the cell suicide signals has stimulated interest in the mechanism of this and related phenomena. It seems probable that mitochondria possess an autonomic system that allows them to commit suicide. This mitoptosis is mediated by reactive oxygen species (ROS), causing opening of the permeability transition pores (PTP) in the inner mitochondrial membrane. Mitoptosis can purify the mitochondrial population in a cell from the ROS‐overproducing organelles. Massive mitoptosis can result in apoptosis (programmed cell death) because of the release of proapoptotic proteins from the mitochondrial intermembrane space, a mechanism purifying tissues from the ROS‐overproducing and other unwanted cells. Large‐scale apoptosis can be used by organisms to eliminate some organs during ontogenesis (organoptosis). In adult organisms, organoptosis of organs of vital importance may entail a programmed death of individuals (phenoptosis). This mechanism might purify kins, communities, and populations from individuals becoming dangerous because of, for example, heavy infection (septic shock). It is hypothesized that aging represents a slow ROS‐linked phenoptosis that eliminates individuals with damaged genomes and gives reproductive advantage to those who succeeded in a better preservation of their genomes from damage.
Inhibition of Ced-3/ICE-related Proteases Does Not Prevent Cell Death Induced by Oncogenes, DNA Damage, or the Bcl-2 Homologue Bak
Authors: McCarthy Nicola J. , Whyte Moira K.B. , Gilbert Christopher S. , Evan Gerard I.
Published: July 2002

There is increasing evidence for a central role in mammalian apoptosis of the interleukin-1β– converting enzyme (ICE) family of cysteine proteases, homologues of the product of the nematode “death” gene, ced-3. Ced-3 is thought to act as an executor rather than a regulator of programmed cell death in the nematode. However, it is not known whether mammalian ICE-related proteases (IRPs) are involved in the execution or the regulation of mammalian apoptosis. Moreover, an absolute requirement for one or more IRPs for mammalian apoptosis has yet to be established. We have used two cell-permeable inhibitors of IRPs, Z-Val-Ala-Asp.fluoromethylketone (ZVAD.fmk) and t-butoxy carbonyl-Asp.fluoromethylketone (BD.fmk), to demonstrate a critical role for IRPs in mammalian apoptosis induced by several disparate mechanisms (deregulated oncogene expression, ectopic expression of the Bcl-2 relative Bak, and DNA damage–induced cell death). In all instances, ZVAD.fmk and BD.fmk treatment inhibits characteristic biochemical and morphological events associated with apoptosis, including cleavage of nuclear lamins and poly-(ADP-ribose) polymerase, chromatin condensation and nucleosome laddering, and external display of phosphatidylserine. However, neither ZVAD.fmk nor BD.fmk inhibits the onset of apoptosis, as characterized by the onset of surface blebbing; rather, both act to delay completion of the program once initiated. In complete contrast, IGF-I and Bcl-2 delay the onset of apoptosis but have no effect on the kinetics of the program once initiated. Our data indicate that IRPs constitute part of the execution machinery of mammalian apoptosis induced by deregulated oncogenes, DNA damage, or Bak but that they act after the point at which cells become committed to apoptosis or can be rescued by survival factors. Moreover, all such blocked cells have lost proliferative potential and all eventually die by a process involving cytoplasmic blebbing.
Assembly of CENP-A into Centromeric Chromatin Requires a Cooperative Array of Nucleosomal DNA Contact Sites
Authors: Shelby Richard D. , Vafa Omid , Sullivan Kevin F.
Published: July 2002

We investigated the requirements for targeting the centromeric histone H3 homologue CENP-A for assembly at centromeres in human cells by transfection of epitope-tagged CENP-A derivatives into HeLa cells. Centromeric targeting is driven solely by the conserved histone fold domain of CENP-A. Using the crystal structure of histone H3 as a guide, a series of CENPA/histone H3 chimeras was constructed to test the role of discrete structural elements of the histone fold domain. Three elements were identified that are necessary for efficient targeting to centromeres. Two correspond to contact sites between histone H3 and nucleosomal DNA. The third maps to a homotypic H3–H3 interaction site important for assembly of the (H3/H4)2 heterotetramer. Immunoprecipitation confirms that CENP-A self-associates in vivo. In addition, targeting requires that CENP-A expression is uncoupled from histone H3 synthesis during S phase. CENP-A mRNA accumulates later in the cell cycle than histone H3, peaking in G2. Isolation of the gene for human CENP-A revealed a regulatory motif in the promoter region that directs the late S/G2 expression of other cell cycle–dependent transcripts such as cdc2, cdc25C, and cyclin A. Our data suggest a mechanism for molecular recognition of centromeric DNA at the nucleosomal level mediated by a cooperative series of differentiated CENP-A–DNA contact sites arrayed across the surface of a CENP-A nucleosome and a distinctive assembly pathway occurring late in the cell cycle.
LI-Cadherin–mediated Cell–Cell Adhesion Does Not Require Cytoplasmic Interactions
Authors: Kreft Bertolt , Berndorff Dietmar , Böttinger Anja , Finnemann Silvia , Wedlich Doris , Hortsch Michael , Tauber Rudolf , Geßner Reinhard
Published: July 2002

The adhesive function of classical cadherins depends on the association with cytoplasmic proteins, termed catenins, which serve as a link between cadherins and the actin cytoskeleton. LI-cadherin, a structurally different member of the cadherin family, mediates Ca2+-dependent cell–cell adhesion, although its markedly short cytoplasmic domain exhibits no homology to this highly conserved region of classical cadherins. We now examined whether the adhesive function of LI-cadherin depends on the interaction with catenins, the actin cytoskeleton or other cytoplasmic components. In contrast to classical cadherins, LI-cadherin, when expressed in mouse L cells, was neither associated with catenins nor did it induce an upregulation of β-catenin. Consistent with these findings, LI-cadherin was not resistant to detergent extraction and did not induce a reorganization of the actin cytoskeleton. However, LI-cadherin was still able to mediate Ca2+dependent cell–cell adhesion.

To analyze whether this function requires any interaction with proteins other than catenins, a glycosyl phosphatidylinositol–anchored form of LI-cadherin (LI-cadherinGPI) was constructed and expressed in Drosophila S2 cells. The mutant protein was able to induce Ca2+-dependent, homophilic cell–cell adhesion, and its adhesive properties were indistinguishable from those of wild type LI-cadherin. These findings indicate that the adhesive function of LI-cadherin is independent of any interaction with cytoplasmic components, and consequently should not be sensitive to regulatory mechanisms affecting the binding of classical cadherins to catenins and to the cytoskeleton. Thus, we postulate that the adhesive function of LI-cadherin is complementary to that of coexpressed classical cadherins ensuring cell–cell contacts even under conditions that downregulate the function of classical cadherins.
β-Actin Messenger RNA Localization and Protein Synthesis Augment Cell Motility
Authors: Kislauskis Edward H. , Zhu Xiao-chun , Singer Robert H.
Published: July 2002

In chicken embryo fibroblasts (CEFs), β-actin mRNA localizes near an actin-rich region of cytoplasm specialized for motility, the lamellipodia. This localization is mediated by isoform-specific 3′-untranslated sequences (zipcodes) and can be inhibited by antizipcode oligodeoxynucleotides (ODNs) (Kislauskis, E.H., X.-C. Zhu, and R.H. Singer. 1994. J. Cell Biol. 127: 441–451). This inhibition of β-actin mRNA localization resulted in the disruption of fibroblast polarity and, presumably, cell motility. To investigate the role of β-actin mRNA in motility, we correlated time-lapse images of moving CEFs with the distribution of β-actin mRNA in these cells. CEFs with localized β-actin mRNA moved significantly further over the same time period than did CEFs with nonlocalized mRNA. Antizipcode ODN treatment reduced this cell translocation while control ODN treatments showed no effect. The temporal relationship of β-actin mRNA localization to cell translocation was investigated using serum addition to serum-deprived cultures. β-actin mRNA was not localized in serum-deprived cells but became localized within minutes after serum addition (Latham, V.M., E.H. Kislauskis, R.H. Singer, and A.F. Ross. 1994. J. Cell Biol. 126:1211–1219). Cell translocation increased over the next 90 min, and actin synthesis likewise increased. Puromycin reduced this cell translocation and blocked this induction in cytosolic actin content. The serum induction of cell movement was also inhibited by antizipcode ODNs. These observations support the hypothesis that β-actin mRNA localization and consequent protein synthesis augment cell motility.
A Role for the Disintegrin Domain of Cyritestin, a Sperm Surface Protein Belonging to the ADAM Family, in Mouse Sperm–Egg Plasma Membrane Adhesion and Fusion
Authors: Yuan Ruiyong , Primakoff Paul , Myles Diana G.
Published: July 2002

Sperm–egg plasma membrane fusion is preceded by sperm adhesion to the egg plasma membrane. Cell–cell adhesion frequently involves multiple adhesion molecules on the adhering cells. One sperm surface protein with a role in sperm–egg plasma membrane adhesion is fertilin, a transmembrane heterodimer (α and β subunits). Fertilin α and β are the first identified members of a new family of membrane proteins that each has the following domains: pro-, metalloprotease, disintegrin, cysteine-rich, EGF-like, transmembrane, and cytoplasmic domain. This protein family has been named ADAM because all members contain a disintegrin and metalloprotease domain. Previous studies indicate that the disintegrin domain of fertilin β functions in sperm–egg adhesion leading to fusion. Full length cDNA clones have been isolated for five ADAMs expressed in mouse testis: fertilin α, fertilin β, cyritestin, ADAM 4, and ADAM 5. The presence of the disintegrin domain, a known integrin ligand, suggests that like fertilin β, other testis ADAMs could be involved in sperm adhesion to the egg membrane. We tested peptide mimetics from the predicted binding sites in the disintegrin domains of the five testis-expressed ADAMs in a sperm–egg plasma membrane adhesion and fusion assay. The active site peptide from cyritestin strongly inhibited (80–90%) sperm adhesion and fusion and was a more potent inhibitor than the fertilin β active site peptide. Antibodies generated against the active site region of either cyritestin or fertilin β also strongly inhibited (80–90%) both sperm–egg adhesion and fusion. Characterization of these two ADAM family members showed that they are both processed during sperm maturation and present on mature sperm. Indirect immunofluorescence on live, acrosome-reacted sperm using antibodies against either cyritestin or fertilin β showed staining of the equatorial region, a region of the sperm membrane that participates in the early steps of membrane fusion. Collectively, these data indicate that a second ADAM family member, cyritestin, functions with fertilin β in sperm–egg plasma membrane adhesion leading to fusion.
Reduction in Surface Urokinase Receptor Forces Malignant Cells into a Protracted State of Dormancy
Authors: Yu W. , Kim J. , Ossowski L.
Published: July 2002

Considerable evidence links urokinase plasminogen activator (uPA) bound to its surface receptor (uPAR) with enhanced invasiveness of cancer cells. By blocking uPAR expression in human epidermoid carcinoma cells (HEp3), we have now identified an additional and novel in vivo function for this receptor by showing that receptor-deficient cells enter a state of dormancy reminiscent of that observed in human cancer metastasis. Its main characteristic is survival without signs of progressive growth. Five clones transfected with a vector expressing uPAR antisense RNA under the β-actin promoter were isolated and shown to have uPAR (at the mRNA and protein levels) reduced by 50 to 80%; four clones, transfected with vector alone and having uPAR levels similar to those of parental cells, served as controls. In confirmation of our previous results, reduced uPAR always coincided with a significantly reduced invasiveness. Each of the control clones produced rapidly growing, highly metastatic tumors within 2 wk of inoculation on chorioallantoic membranes (CAMs) of chick embryos. In contrast, each of the clones with low surface uPAR, whose proliferation rate in culture was indistinguishable from controls, remained dormant for up to 5 mo when inoculated on CAMs. Thus, the reduction in uPAR altered the phenotype of HEp3 tumor cells from tumorigenic to dormant. Although protracted, tumor dormancy was not permanent since in spite of maintaining low uPAR levels, each of the in vivo–passaged antisense clones eventually reemerged from dormancy to initiate progressive growth and to form metastases at a level of 20 to 90% of that of fully malignant control. This observation suggested that other factors, whose expression is dependent on cumulative and prolonged in vivo effects, can compensate for the lack of a full complement of surface uPAR required for the expression of malignant properties. These “reemerged,” uPAR-deficient clones were easily distinguishable from the vector-transfected controls by the fact that after only 1 wk in culture, the invasion of CAM by all five clones and tumorigenicity of four of the five clones were reduced back to the values observed before in vivo maintenance. In contrast, dissociated and in vitro–grown cells of control tumors were fully invasive and produced large, metastatic tumors when reinoculated on CAMs. Quantitation of the percent of apoptotic and S-phase cells in vivo, in the control and uPAR-deficient, dormant clones, showed that the mechanism responsible for the dormancy was a diminished proliferation.
A Novel Rab9 Effector Required for Endosome-to-TGN Transport
Authors: Díaz Elva , Schimmöller Frauke , Pfeffer Suzanne R.
Published: July 2002

Rab9 GTPase is required for the transport of mannose 6-phosphate receptors from endosomes to the trans-Golgi network in living cells, and in an in vitro system that reconstitutes this process. We have used the yeast two-hybrid system to identify proteins that interact preferentially with the active form of Rab9. We report here the discovery of a 40-kD protein (p40) that binds Rab9–GTP with roughly fourfold preference to Rab9–GDP. p40 does not interact with Rab7 or K-Ras; it also fails to bind Rab9 when it is bound to GDI. The protein is found in cytosol, yet a significant fraction (∼30%) is associated with cellular membranes. Upon sucrose density gradient flotation, membrane- associated p40 cofractionates with endosomes containing mannose 6-phosphate receptors and the Rab9 GTPase. p40 is a very potent transport factor in that the pure, recombinant protein can stimulate, significantly, an in vitro transport assay that measures transport of mannose 6-phosphate receptors from endosomes to the trans-Golgi network. The functional importance of p40 is confirmed by the finding that anti-p40 antibodies inhibit in vitro transport. Finally, p40 shows synergy with Rab9 in terms of its ability to stimulate mannose 6-phosphate receptor transport. These data are consistent with a model in which p40 and Rab9 act together to drive the process of transport vesicle docking.
The Kinetics of L-selectin Tethers and the Mechanics of Selectin-mediated Rolling
Authors: Alon Ronen , Chen Shuqi , Puri Kamal D. , Finger Erik B. , Springer Timothy A.
Published: July 2002

Two mechanisms have been proposed for regulating rolling velocities on selectins. These are (a) the intrinsic kinetics of bond dissociation, and (b) the reactive compliance, i.e., the susceptibility of the bond dissociation reaction to applied force. To determine which of these mechanisms explains the 7.5–11.5-fold faster rolling of leukocytes on L-selectin than on E- and P-selectins, we have compared the three selectins by examining the dissociation of transient tethers. We find that the intrinsic kinetics for tether bond dissociation are 7–10-fold more rapid for L-selectin than for E- and P-selectins, and are proportional to the rolling velocities through these selectins. The durations of pauses during rolling correspond to the duration of transient tethers on low density substrates. Moreover, applied force increases dissociation kinetics less for L-selectin than for E- and P-selectins, demonstrating that reactive compliance is not responsible for the faster rolling through L-selectin. Further measurements provide a biochemical and biophysical framework for understanding the molecular basis of rolling. Displacements of tethered cells during flow reversal, and measurements of the distance between successive pauses during rolling provide estimates of the length of a tether and the length of the adhesive contact zone, and suggest that rolling occurs with as few as two tethers per contact zone. Tether bond lifetime is an exponential function of the force on the bond, and the upper limit for the tether bond spring constant is of the same order of magnitude as the estimated elastic spring constant of the lectin–EGF unit. Shear uniquely enhances the rate of L-selectin transient tether formation, and conversion of tethers to rolling adhesions, providing further understanding of the shear threshold requirement for rolling through L-selectin.
Fas Induces Cytoplasmic Apoptotic Responses and Activation of the MKK7-JNK/SAPK and MKK6-p38 Pathways Independent of CPP32-like Proteases
Authors: Toyoshima Fumiko , Moriguchi Tetsuo , Nishida Eisuke
Published: July 2002

IL-1β converting enzyme (ICE) family cysteine proteases are subdivided into three groups; ICE-, CPP32-, and Ich-1–like proteases. In Fas-induced apoptosis, activation of ICE-like proteases is followed by activation of CPP32-like proteases which is thought to be essential for execution of the cell death. It was recently reported that two subfamily members of the mitogen-activated protein kinase superfamily, JNK/SAPK and p38, are activated during Fas-induced apoptosis. Here, we have shown that MKK7, but not SEK1/ MKK4, is activated by Fas as an activator for JNK/ SAPK and that MKK6 is a major activator for p38 in Fas signaling. Then, to dissect various cellular responses induced by Fas, we used several peptide inhibitors for ICE family proteases in Fas-treated Jurkat cells and KB cells. While Z-VAD-FK which inhibited almost all the Fas-induced cellular responses blocked the activation of JNK/SAPK and p38, Ac-DEVD-CHO and Z-DEVD-FK, specific inhibitors for CPP32-like proteases, which inhibited the Fas-induced chromatin condensation and DNA fragmentation did not block the activation of JNK/SAPK and p38. Interestingly, these DEVD-type inhibitors did not block the Fas-induced morphological changes (cell shrinkage and surface blebbing), induction of Apo2.7 antigen, or the cell death (as assessed by the dye exclusion ability). These results suggest that the Fas-induced activation of the JNK/SAPK and p38 signaling pathways does not require CPP32-like proteases and that CPP32-like proteases, although essential for apoptotic nuclear events (such as chromatin condensation and DNA fragmentation), are not required for other apoptotic events in the cytoplasm or the cell death itself. Thus, the Fas signaling pathway diverges into multiple, separate processes, each of which may be responsible for part of the apoptotic cellular responses.
Ultrastructural Organization of Bovine Chromaffin Cell Cortex—Analysis by Cryofixation and Morphometry of Aspects Pertinent to Exocytosis
Authors: Plattner Helmut , Artalejo Antonio R. , Neher Erwin
Published: July 2002

We have analyzed ultrathin sections from isolated bovine chromaffin cells grown on plastic support, after fast freezing, by quantitative electron microscopy. We determined the size and intracellular distribution of dense core vesicles (DVs or chromaffin granules) and of clear vesicles (CVs). The average diameter of DVs is 356 nm, and that of CVs varies between 35–195 nm (average 90 nm). DVs appear randomly packed inside cells. When the distance of the center of DVs to the cell membrane (CM) is analyzed, DV density is found to decrease as the CM is approached. According to Monte Carlo simulations performed on the basis of the measured size distribution of DVs, this decay can be assigned to a “wall effect.” Any cortical barrier, regardless of its function, seems to not impose a restriction to a random cortical DV packing pattern. The number of DVs closely approaching the CM (docked DVs) is estimated to be between 364 and 629 (average 496), i.e., 0.45 to 0.78 DVs/μm2 CM. Deprivation of Ca2+, priming by increasing [Ca2+]i, or depolarization by high [K+]e for 10 s (the effect of which was controlled electrophysiologically and predicted to change the number of readily releasable granules [RRGs]) does not significantly change the number of peripheral DVs. The reason may be that (a) structural docking implies only in part functional docking (capability of immediate release), and (b) exocytosis is rapidly followed by endocytosis and replenishment of the pool of docked DVs. Whereas the potential contribution of DVs to CM area increase by immediate release can be estimated at 19–33%, that of CVs is expected to be in the range of 5.6–8.0%.
Cytoplasmic Dynein and Dynactin Are Required for the Transport of Microtubules into the Axon
Authors: Ahmad Fridoon J. , Echeverri Christophe J. , Vallee Richard B. , Baas Peter W.
Published: July 2002

Previous work from our laboratory suggested that microtubules are released from the neuronal centrosome and then transported into the axon (Ahmad, F.J., and P.W. Baas. 1995. J. Cell Sci. 108: 2761–2769). In these studies, cultured sympathetic neurons were treated with nocodazole to depolymerize most of their microtubule polymer, rinsed free of the drug for a few minutes to permit a burst of microtubule assembly from the centrosome, and then exposed to nanomolar levels of vinblastine to suppress further microtubule assembly from occurring. Over time, the microtubules appeared first near the centrosome, then dispersed throughout the cytoplasm, and finally concentrated beneath the periphery of the cell body and within developing axons. In the present study, we microinjected fluorescent tubulin into the neurons at the time of the vinblastine treatment. Fluorescent tubulin was not detected in the microtubules over the time frame of the experiment, confirming that the redistribution of microtubules observed with the experimental regime reflects microtubule transport rather than microtubule assembly. To determine whether cytoplasmic dynein is the motor protein that drives this transport, we experimentally increased the levels of the dynamitin subunit of dynactin within the neurons. Dynactin, a complex of proteins that mediates the interaction of cytoplasmic dynein and its cargo, dissociates under these conditions, resulting in a cessation of all functions of the motor tested to date (Echeverri, C.J., B.M. Paschal, K.T. Vaughan, and R.B. Vallee. 1996. J. Cell Biol. 132: 617–633). In the presence of excess dynamitin, the microtubules did not show the outward progression but instead remained near the centrosome or dispersed throughout the cytoplasm. On the basis of these results, we conclude that cytoplasmic dynein and dynactin are essential for the transport of microtubules from the centrosome into the axon.