Myosin IIA Heavy Chain (Ser-1916), Phosphospecific Antibody

On-muscle myosin II is an actin-based motor protein essential to cell motility, division, migration, adhesion and polarity. This myosin forms a hexameric complex comprised of two heavy chains (NMHC-II), two essential light chains, and two regulatory light chains (RLC) . In vertebrates, there are three NMHC-II isoforms (NMHC-IIA, NMHC-IIB, and NMHC-IIC), which exhibit distinct patterns of expression in cells and tissues. Regulation of NMHC-II activity occurs through RLC and HC phosphorylation. RLCs are phosphorylated at Thr-18 and Ser-19, which activates myosin II motor activity and promotes filament stability. By contrast, PKC phosphorylation of Ser-1/Ser-2 and Thr-9 in RLC may decrease activated myosin II interaction with actin. Several kinases phosphorylation NMHC-II isoforms directly. TRPM7 phosphorylates Thr-1800, Ser-1803, and Ser-1808, which reduces NMHC-IIA incorporation into the actin cytoskeleton. PKC phosphorylates NMHC-IIA on Ser-1916 and NMHC-IIB on multiple tailpiece serines leading to inhibition of filament assembly. Casein kinase II phosphorylates NMHC-IIA on Ser-1943 and increases disassembly of NMHC-IIA filaments.

Phospho-Myosin IIA Heavy Chain (Ser-1916) synthetic peptide (coupled to KLH) corresponding to amino acid residues surrounding Ser-1916 in human myosin IIA heavy chain.

This antibody was cross-adsorbed to unphosphorylated Myosin IIA Heavy Chain (Ser-1916) peptide before affinity purification using phospho-Myosin IIA Heavy Chain (Ser-1916) peptide (without carrier) . The antibody detects a 200 kDa* protein corresponding to Myosin IIA Heavy Chain on SDS-PAGE immunoblots of human A431 cells treated with Calyculin A. This reactivity is removed after treatment with lambda phosphatase. This peptide sequence is highly conserved in rat and mouse myosin IIA heavy chain.