Myosin regulatory subunit that plays a role to maintain muscle integrity during early development (PubMed:32707087). Plays a role in muscle contraction (PubMed:32707087). Myosin is a hexamer of 2 heavy chains and 4 light chains. Expressed in both embryos and adult fish, and the expression is specifically in fast skeletal muscle. Knockout myl11a mutant have reduced trunk contractile force and complete pectoral fin paralysis. Muscle weakness is most pronounced in an appendicular muscle and is explained by reduced myosin activity and fiber degeneration.