Mlc2p is a regulatory light chain (RLC) for Myo1p, a type II myosin, while Mlc1p is the essential light chain (ELC) for Myo1p. Mlc2p localizes to the bud neck through an interaction with the IQ2 domain of Myo1p. Deletion of MLC2 causes defect in the disassembly of the Myo1p ring at the end of ring contraction (1).

MLC2 displays significant sequence homology to calmodulin or myosin light chain related proteins. Like other light chains, Mlc2p contains an EF hand and a serine residue, both close to the N-terminus, and the serine corresponds to one of the activating phosphorylation sites in the human type II myosin RLC (1 and references therein). The family of RLCs for nonmuscle type II myosins share limited sequence homology and their function in modulating the heavy-chain activity depends on the organismal complexity. Mutations in the fly RLC gene, spaghetti-squash, cause lethality (1 and references therein), while deletion of MLC2 in S. cerevisiae produces a defect in the disassembly of the Myo1p ring.

Last updated: 2007-02-15