Tropomodulin: An Important Player in Cardiac Myofibrillogenesis
Tropomodulin has been studied intensively since it was first reported in 1987 as a tropomyosin binding protein associated with the erythrocyte membrane skeleton (Fowler, 1987). The study of tropomodulin’s role in heart myofibrillogenesis was initiated after the discovery that in mature skeletal muscle tropomodulin was localized to the pointed (slow-growing) ends of the thin filaments (Fowler et al., 1993). Subsequent in vitro studies demonstrated that tropomodulin is a potent actin filament pointed-end capping protein, functioning to prevent actin filaments from elongating or shrinking (Weber et al., 1994). The results of the studies that will be discussed here demonstrate that tropomodulin plays a critical role in maintaining the length of thin filaments within sarcomeres, in the physiologic function (contractile activity) of cardiac myocytes, and in the organogenesis of the heart. Investigations on the properties of this molecule continue to provide new insights into cytoskeletal protein dynamics.
KeywordsActin Filament Cardiac Myocytes Thin Filament Filament Length Lens Fiber Cell
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