book reviews Physics of the

Mechanics of Motor and the Cytoskeleton by Jonathan Howard Palgrave •April 2001 Hardback £44.99/$62.95 Jonathan Scholey

pectacular progress has been made in properties of molecules in part 1, the This text addresses our understanding of the physical biophysical properties of cytoskeletal fila- Sprocesses that underlie the functions ments in part 2 and the properties and mech- fundamental questions about and mechanisms of cytoskeletal proteins. For anism of motor proteins in part 3. Similar to example, the atomic structures of , Howard Berg’s classic text, Random Walks in the nature of the forces that and several motor proteins have been Biology (Princeton University Press), part 1 determined and quantitative models describ- clearly explains how ‘life at low Reynold’s act to generate in the ing the mechanisms of force generation by number’ — where viscous forces and thermal filament polymerization/depolymerization fluctuations are so dominant — differs from subcellular world. and motor-protein action have been pro- life at the macroscopic scale and there are posed. Moreover, advances in optical tech- many interesting surprises. For example, I niques have allowed biophysicists to observe had always thought of globular proteins as and manipulate motor proteins and their being like pliable rubber balls, instead of the the mechanics and movements of cells. dynamic tracks in a way that allows their hard plastic spheres that Joe describes. Most No rose comes without its thorns, howev- activities to be measured directly as they cell biologists will be acquainted with the er, and there are features of the book that, in operate at the nanometer, piconewton and material covered in parts 2 and 3 but the my opinion, could be improved. For exam- millisecond scales. These amazing advances author delves deeper than usual into the ple, problem sets are appended to all the in cytoskeletal biophysics are the focus of the physical principles that underlie the phe- chapters in section 1, but not to most of those book, Mechanics of Motor Proteins and the nomena being described, and this in turn in the subsequent sections. This is unfortu- Cytoskeleton by Jonathan (Joe) Howard, who underlies the book’s great strength. In each of nate because the material presented on is a leading expert in this field. Joe has clearly the sections, general principles are empha- motor and cytoskeletal filaments is quite put an enormous amount of work into this sized, relevant equations that can be used to amenable to quantitative problem solving. In project, and the result is an excellent text that develop quantitative descriptions of addition, solutions to the problem sets are is unique and original; by explaining how the cytoskeletal behaviour are included, and the not provided. Generally, I found that the mechanical properties of the cytoskeleton main text is supplemented with illustrative material in the first section could have been emerge from basic physical concepts, it fills a and interesting cell-biological examples. better integrated with the other two sections. void and represents an extremely valuable Mechanics of Motor Proteins and the Some explanations in the text seem unneces- addition to the cell-biology literature. Cytoskeleton is written for students of physics sarily difficult — this is not helped by several This text addresses fundamental ques- or biology who are interested in how the typographical errors and some confusing use tions about the nature of the forces that act to mechanical properties of protein molecules of motor nomenclature. Inevitably, what is generate motion in the subcellular world. For contribute to cell structure and motility. It is included reflects Joe’s own tastes and opin- example, what are the mechanical properties an advanced-level text, and the students who ions, and readers should be prepared to sup- of individual proteins and protein polymers benefit from it will have already mastered plement their reading with key papers that (are they hard, soft, stiff or flexible), how do basic cell biology, physics, biochemistry and are not cited here. actin and tubulin subunits polymerize into calculus. The text could be used to supple- But overall, this text is a very valuable filaments, how do the ends of the filaments ment a graduate-level class on the biophysics contribution to the literature. It explains remain attached to an object in a way that of the cytoskeleton and it will be a valuable the basic physical principles governing the allows coupling of subunit addition or disso- resource for the large number of graduate behaviour of cytoskeletal filaments and ciation to the exertion of pushing or pulling students, post-docs and other cell-biology motors, it pulls together a large amount of forces on that object, how do motor proteins researchers who study the cytoskeleton. conceptual and technical information, and generate force and move along a cytoskeletal Being a cell biologist who appreciates quanti- in its current form it should occupy a place track, what are the roles of thermal energy tative physical descriptions of cellular on the bookshelves of all cell biologists and energy derived from nucleotide hydroly- processes but who is not a card-carrying who study the cytoskeleton. I highly rec- sis in force generation and movement, and physicist, I found working through some of ommend it! how do these forces contribute to cell struc- the material in the book heavy going but very Jonathan Scholey, Professor of Cell Biology, ture, mechanics and motility? worthwhile. The reward has been an Center for Genes and Development and To address these questions the book is improved understanding of the fascinating Section of Molecular and Cellular Biology, organized into three sections that cover the relationship between the fundamental physi- University of California at Davis, Davis, CA physical principles governing the mechanical cal properties of individual molecules and 95616, USA; e-mail: [email protected]

E62 NATURE CELL BIOLOGY VOL 4 MARCH 2002 http://cellbio.nature.com

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