Plays a role in the regulation of contractile properties of both striated and smooth muscles. When unphosphorylated, may inhibit myosin dephosphorylation. Phosphorylation at Ser-299 reduces this inhibitory activity (By similarity).
Subcellular locations: Cytoplasm, Myofibril, Cytoplasm, Myofibril, Sarcomere, I band, Cytoplasm, Myofibril, Sarcomere, M line, Nucleus
Colocalizes with MYH2. In its unphosphorylated state, localizes to the cytoplasm (By similarity). Phosphorylation at Ser-301 promotes translocation to the nucleus (By similarity).
Expressed in striated muscles, specifically in type 2a fibers (at protein level).