Mechanics of the Cell

Mechanics of the Cell Edited by David Boal New York: Cambridge University Press (2002). 406 pp. $45.00Many of the critical aspects of biological functions can only be understood through a melding of the physics (often mechanics) and the biochemistry involved. From the morphological changes in gastrulation or the vascularization of cancerous tissue to the unfolding of DNA in transcription, biological functions rely upon an orchestrated feedback between mechanical forces and biochemical activities. In our attempts to better understand biological functions, a complete description of the proteins and enzymatic activities involved, although important, provide only a partial picture. Further, although many biological scientists have distaste for them, equations provide a concise way to describe and predict physical aspects of cell behavior. In addition, there is a dramatic increase of interest in biological questions among physicists who enjoy the mathematical description of cell functions. Thus, there is an urgent need to incorporate an understanding of the mechanics involved in the normal functioning of a cell, and the recent book by Boal speaks nicely to that issue.Designed as a text for a one-semester course on cell mechanics, Mechanics of the Cell provides an excellent introduction to the basic mechanics of cytoskeletons and membranes (targeted for junior or senior undergraduate and beginning graduate students). It fills a unique niche between the macroscopic mechanics of the Fung book (Biomechanics: Mechanical Properties of Living Tissues, Y.C. Fung, Springer-Verlag, 1993) and the molecular mechanics of the Howard book (Mechanics of Motor Proteins and the Cytoskeleton, Jonathan Howard, Sinauer Associates, 2001). In addition, Boal deals with membrane mechanics and cell-cell adhesion, which are critical aspects at the cellular, but not the higher or lower levels.The topic of cytoskeletal mechanics, from filament persistence length to three-dimensional networks, is considered in a format adapted to the characteristics of cells. There are multiple references to relevant literature, such as the effect of avidin crosslinking of biotinylated actin filaments on the mechanics of the actin gel. The treatment of DNA and RNA mechanics is brief. However, there is enough basic description of the mechanics to enable one to adapt the equations to other biological materials such as DNA or RNA. To gain a real understanding of the material, it is important for the reader to try and solve or at least consider the problems at the end of each chapter. To be successful in solving the problems, you may want to dust off your college calculus book, particularly if it has had time to collect significant dust.Biological membranes are unusual in their mechanical properties in that they are essentially two-dimensional inelastic fluids constrained by attachment to the cytoskeleton. Membrane mechanics chapters have a particularly good description of the factors that lead to the formation of a bilayer. In the section on cell-cell interactions, there are good treatments of the critical events of cell-cell binding. The details on membrane fluctuations are probably of greater interest to physicists than biologists. Overall, the treatment of membranes is excellent and it can be of great benefit to all to have a better physical feel for membranes. This is especially important in light of popularly held misconceptions such as membrane flow driving motility, membrane stretching, or even large membrane rafts that are inconsistent with the physical properties of membranes.In terms of possible improvements, additional figures would be useful, as would further tables of properties such as those provided for the membrane chapter. Expansion of the discussion of experimental problems as case examples would also help. As a text for a course, the essentials are present in this book, from the basic explanations of the equations to a good set of sample problems.In general, this book provides a good introduction to the physical description of the mechanical properties of cells and membranes. Readers will benefit from a background in calculus, although some topics can be understood without complex mathematics. All who deal with the cytoskeleton and membranes are encouraged to increase their understanding of the physical properties of those materials, since the physical properties can influence or control biochemical activities in integrated cell functions.