The Tropomodulin (Tmod) family consist of four Tmods (Tmods 1-4) and three larger variants termed leiomodins (Lmods 1-3), which are expressed in a tissue-specific and developmentally regulated fashion []. Members of the Tmod family are actin filament pointed-end-capping proteins that regulate actin subunit association and dissociation from pointed ends in a tropomyosin-dependent manner [].Tropomodulin-4 (Tmod4) binds with F-actin []. Tmod1 and Tmod4 are sarcomeric Tmods that maintain thin filament stability and correctly specified thin filament lengths in cardiac muscles via their interactions with terminal tropomyosins and their ability to regulate actin subunit exchange at pointed ends [].
The Tropomodulin (Tmod) family consist of four Tmods (Tmods 1-4) and three larger variants termed leiomodins (Lmods 1-3), which are expressed in a tissue-specific and developmentally regulated fashion []. Members of the Tmod family are actin filament pointed-end-capping proteins that regulate actin subunit association and dissociation from pointed ends in a tropomyosin-dependent manner [].Tropomodulin1 (Tmod1) was originally known to as E-Tmod, as it was first identified as a binding partner of tropomyosin (TM) in red blood cells (RBC) []. Tmod1 is predominantly expressed in terminally differentiated, post-mitotic cells (such as RBCs, lens fibre cells, neurons, andstriated muscle). Tmod1 binds with F-actin []. It is essential for stabilising F-actin at cell-cell junctions, which may be required for maintenance of cell shapes during embryonic cardiac morphogenesis []. It also regulates actin dynamics to control the precise lengths of the long alpha/beta tropomyosin-coated actin filaments in mature cardiac myofibrils [, ]. Tmod1 and Tmod4 maintain thin filament stability and correctly specified thin filament lengths in cardiac muscles via their interactions with terminal tropomyosins and their ability to regulate actin subunit exchange at pointed ends []. Tmod1's structure has been solved [].
