and Historical Perspective -- and Historical Perspective -- Genes and Their Expression -- Structure and Evolution of Tropomyosin Genes -- Tropomyosin Exons as Models for Alternative Splicing -- Tropomyosin Gene Expression in Vivo and in Vitro -- Protein Structure -- Tropomyosin: Function Follows Structure -- Dimerization of Tropomyosins -- Role in Muscle Function -- Cooperative Binding of Tropomyosin to Actin -- Tropomyosin and the Steric Mechanism of Muscle Regulation -- Role of Tropomyosin in the Regulation of Contraction in Smooth Muscle -- Tropomyosin in Human Disease -- Tropomyosin as a Regulator of Cancer Cell Transformation -- The Role of Tropomyosin in Heart Disease -- Tropomyosins in Skeletal Muscle Diseases -- Tropomyosins in Human Diseases: Ulcerative Colitis -- Tropomyosin Directed Regulation of the Cytoskeleton -- Tropomyosin Function in Yeast -- Isoform Sorting of Tropomyosins -- Human Tropomyosin Isoforms in the Regulation of Cytoskeleton Functions -- Mechanisms of Tropomyosin Function -- Tropomyosins Regulate the Impact of Actin Binding Proteins on Actin Filaments -- Tropomyosin and ADF/Cofilin as Collaborators and Competitors -- Caldesmon and the Regulation of Cytoskeletal Functions -- Tropomyosins as Discriminators of Myosin Function -- Tropomodulin/Tropomyosin Interactions Regulate Actin Pointed End Dynamics -- Conclusion -- Emerging Issues for Tropomyosin Structure, Regulation, Function and Pathology.

A recent review of one of my grant applications commented on the ‘rediscovery of tropomyosin’. I was tempted to write back in my rebuttal to the reviewer that I didn’t realise it had been lost. Uncharacteristic maturity prevailed and I resisted the temptation, but I was struck by the underlying observation that research on the str- ture and function of tropomyosin has been somewhat invisible, particularly in terms of the cytoskeleton isoforms. So, how can it be that one of the two major components of the actin filament has been so thoroughly overlooked? I suspect that the answer is disappointingly pedestrian. Whereas the biochemistry of the 1980s revealed the potential of tropomyosin isoforms to diversify the function of actin filaments, the subsequent disenchantment with isoform biology in general in the 1990s inhibited growth of this field. With the development of more sophisticated experimental - proaches we are now seeing a growing realisation of the importance of tropomyosin in regulating actin filaments beyond its pivotal role in muscle contraction. The opportunity to edit this book came at a time when we had written several reviews on different aspects of tropomyosin function and I had just finished the background reading for a comprehensive review of tropomyosin biology. I realised that the field was simply beyond the capacity of any one person to do the field j- tice.