Science direct gives an overview about the actin’s function:
Based on the frequency of publications in PubMed we advise the following Anti Actin smooth muscle antibodies for paraffin fixed tissues or Frozen tissues. Clone 647 is not suited for paraffin fixed tissues even after target retrieval.
Clone: 1A4, Mouse Monoclonal antibody-Human
Clone: ASM-1, Mouse Monoclonal antibody-Human; frozen, IH
Clone: CL-257, Mouse Monoclonal antibody
Clone: 647, Mouse Monoclonal antibody-Human, Chicken; NO paraffin
Clone: HHF35, Mouse Monoclonal antibody-Human
Dropa actin staining of Rat cells in this movie
In a relaxed muscle, tropomyosin blocks the attachment site for the myosin crossbridge, thus preventing the muscle cell is stimulated to contract by an action potential, calcium channels open in the sarcoplasmic membrane and release calcium Oct 12, 2019 This gene is a member of the tropomyosin family of highly conserved, widely distributed actin-binding proteins involved in the contractile system of striated and smooth muscles and the cytoskeleton of non-muscle cells. Selected actin filaments in most cells are stabilized by the binding of tropomyosin, an elongated protein that binds simultaneously to seven adjacent actin subunits in one protofilament The binding of tropomyosin along an actin filament can prevent the filament from interacting with other proteins; for this reason, the regulation of tropomyosin binding is an important step in muscle contraction.
The thin filaments of sarcomeres consist of skeletal muscle α-actin (αsk-actin), whereas extrasarcomeric membrane compartments contain cytoplasmic γ-actin (γcyto-actin; Craig and Pardo, 1983 ; Pardo et al., 1983 ; Otey et al., 1988 ; Rybakova et al., 2000 ). The lengths of αsk-actin thin filaments are determined by αsk-actin monomer exchange at pointed ends, which is in turn regulated by tropomodulins (Tmods), a family of tropomyosin (Tm)-binding and pointed end-capping proteins ( Gregorio et al., 1995 ; Littlefield et al., 2001 ; Littlefield and Fowler, 2008 ). In contrast, it is unknown whether Tmods regulate the lengths, stability, and/or organization of γcyto-actin filaments, which are proposed to fortify the sarcolemma through their interactions with dystrophin and β2-spectrin at costameres ( Craig and Pardo, 1983 ; Porter et al., 1992 , 1997 ; Renley et al., 1998 ; Rybakova et al., 2000 ; Williams et al., 2001 ). γcyto-Actin is dispensable for skeletal muscle development, but its absence can produce muscle weakness, indicating that γcyto-actin plays a role in muscle mechanical performance ( Sonnemann et al., 2006 ; Belyantseva et al., 2009 ). Surprisingly, γcyto-actin-deficient muscles do not exhibit sarcolemmal defects, leaving the functional role of γcyto-actin in muscle membranes uncertain ( Sonnemann et al., 2006 ). However, up to 10-fold up-regulation of γcyto-actin has been observed in various animal models of muscular dystrophy, including dystrophin-deficient mdx mice, α-sarcoglycan-null mice, and golden retriever muscular dystrophy ( Hanft et al., 2006 , 2007 ).
The importance of γcyto-actin under pathological conditions suggests possible functions for γcyto-actin in the structural biology of other striated muscle membranes such as the sarcoplasmic reticulum (SR). While a host of proteins are known to nucleate filament assembly, cap the fast-growing (barbed) ends of actin filaments, or bind along the sides of filaments, only the tropomodulin (Tmod) family of proteins caps the slow-growing (pointed) filament ends 7 – 12 Tmods (~40 kDa) are present in all metazoans, including flies and worms 13 – 15 , with four Tmod isoforms expressed in mammalian cells; Tmod1 is predominantly expressed in terminally differentiated, postmitotic cells (such as erythrocytes, lens fiber cells, neurons, and striated muscle), Tmod2 is in neuronal tissues, Tmod3 is nearly ubiquitous, and Tmod4 is restricted to skeletal muscle fibers 16 – 26 Thus, the Tmod isoforms relevant to actin filament regulation in mammalian striated muscles are Tmod1, Tmod3, and Tmod4.