In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.

Two-component signal transduction pathways comprising histidine protein kinases (HPKs) and their response regulators (RRs) are widely used to control bacterial responses to environmental challenges. Some bacteria have over 150 different two-component pathways, and the specificity of the phosphotransfer reactions within these systems is tightly controlled to prevent unwanted crosstalk. One of the best understood two-component signalling pathways is the chemotaxis pathway. Here, we present the 1.40 A crystal structure of the histidine-containing phosphotransfer domain of the chemotaxis HPK, CheA(3), in complex with its cognate RR, CheY(6). A methionine finger on CheY(6) that nestles in a hydrophobic pocket in CheA(3) was shown to be important for the interaction and was found to only occur in the cognate RRs of CheA(3), CheY(6), and CheB(2). Site-directed mutagenesis of this methionine in combination with two adjacent residues abolished binding, as shown by surface plasmon resonance studies, and phosphotransfer from CheA(3)-P to CheY(6). Introduction of this methionine and an adjacent alanine residue into a range of noncognate CheYs, dramatically changed their specificity, allowing protein interaction and rapid phosphotransfer from CheA(3)-P. The structure presented here has allowed us to identify specificity determinants for the CheA-CheY interaction and subsequently to successfully reengineer phosphotransfer signalling. In summary, our results provide valuable insight into how cells mediate specificity in one of the most abundant signalling pathways in biology, two-component signal transduction.
Using Structural Information to Change the Phosphotransfer Specificity of a Two-Component Chemotaxis Signalling Complex

Excessive exposure to estradiol represents the main risk factor for endometrial cancer. The abnormally high estradiol levels in the endometrium of women with endometrial cancer are most likely due to overproduction by the tumour itself. Endometrial cancer cells express the genes encoding the steroidogenic enzymes involved in estradiol synthesis. Here we used RT-PCR and Western blot to show that the nuclear receptors SF1 and LRH1, two well-known regulators of steroidogenic gene expression in gonadal and adrenal cells, are also expressed in endometrial cancer cell lines. By transient transfections, we found that SF1 and LRH1, but not the related nuclear receptor NUR77, can activate the promoters of three human steroidogenic genes: STAR, HSD3B2, and CYP19A1 PII. Similarly, forskolin but not PMA, could activate all three promoters. In addition, we found that both SF1 and LRH1 can transcriptionally cooperate with the AP-1 family members c-JUN and c-FOS, known to be associated with enhanced proliferation of endometrial carcinoma cells, to further enhance activation of the STAR, HSD3B2, and CYP19A1 PII promoters. All together, our data provide novel insights into the mechanisms of steroidogenic gene expression in endometrial cancer cells and thus in the regulation of estradiol biosynthesis by tumour cells.
The nuclear receptors SF1 and LRH1 are expressed in endometrial cancer cells and regulate steroidogenic gene transcription by cooperating with AP-1 factors.

Solitary metastatic brain tumors are the most common intracranial neoplasms encountered by neurosurgeons. Surgical resection of brain metastasis with whole brain radiotherapy (WBR) significantly increases survival in comparison with WBR alone. Stereotactic radiosurgery (SR) seems to provide results that are similar to those of surgical resection. To analyze the economic efficiency of these different treatments, we compared the results of surgical resection and SR as reported in the medical literature between 1974 and 1994. We included studies in which: 1) at least 75% of patients received WBR; 2) study dates were in the computed tomography era (after 1975); 3) operative morbidity, mortality, and median survival were reported; 4) study dates were not included in a more recent update or review; 5) tumor histologies were reported; and 6) the cobalt-60 gamma unit was used for SR. Three surgical resection studies and one SR study met all entry requirements. The WBR baseline was developed from two prospective, randomized trials and used for incremental cost effectiveness analysis. We developed a model of typical resource usage for uncomplicated procedures, reported complications, and subsequent craniotomies (for recurrent tumor or radiation necrosis) for both treatment options. Costs were estimated from the societal viewpoint using the 1992 Medicare Provider Analysis and Review database with average cost:charge ratios for surgery and WBR. A survey of capital and operating costs from five sites was used for radiosurgery. Our analysis revealed that radiosurgery had a lower uncomplicated procedure cost ($20,209 versus $27,587), a lower average complication cost per case ($2,534 versus $2,874), and a lower total cost per procedure ($22,743 versus $30,461), was more cost effective ($24,811 versus $32,149 per life year), and had a better incremental cost effectiveness ($40,648 versus $52,384 per life year) than surgical resection. A sensitivity analysis revealed that large changes in key assumptions would be required to change the analysis outcome. Equalization of the incremental cost effectiveness of the two treatments would require one of the following: 1) a 38.7% reduction in SR annual case volume, 2) a 34.7% increase in SR procedure cost, 3) a 18.8% reduction in surgical resection procedure cost, 4) a 240.5% increase in SR morbidity cost, 5) a 12.7% reduction in SR median survival, 6) a 16.8% increase in surgical resection median survival. Elimination of all surgical resection morbidity cost would still result in superior incremental cost effectiveness for SR.(ABSTRACT TRUNCATED AT 400 WORDS)
The cost effectiveness of stereotactic radiosurgery versus surgical resection in the treatment of solitary metastatic brain tumors.