Regulation of myosin II during cytokinesis in higher eukaryotes.
Cellular myosin II is the principal motor responsible for cytokinesis. In higher eukaryotes, phosphorylation of the regulatory light chain (MLC) of myosin II is a primary means of activating myosin II and is known to be crucial for the execution of cell division. Because signals transmitted by the mitotic spindle coordinate key spatial and temporal aspects of cytokinesis, such signals should ultimately function to activate myosin II. Thus, it follows that identification of regulatory factors involved in MLC phosphorylation should elucidate the nature of spindle-derived regulatory signals and lead to a model for how they control cytokinesis. However, the identity of these upstream molecules remains elusive. This review (which is part of the Cytokinesis series) summarizes current views of the regulatory pathway controlling MLC phosphorylation and features four candidate molecules that are likely immediate upstream myosin regulators. I discuss proposed functions for MLCK, ROCK, citron kinase and myosin phosphatase during cytokinesis and consider the possibility of a link between these molecules and the signals transmitted by the mitotic spindle.
Matsumura
Fumio
F
Department of Molecular Biology and Biochemistry, Rutgers University, 604 Allison Road, Piscataway, NJ 08855, USA. matsumur@rci.rutgers.edu
D000818:Animals; D018797:Cell Cycle Proteins / Q000378:metabolism; D048749:Cytokinesis / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D018994:Myosin Light Chains / Q000378:metabolism*; D024462:Myosin Type II / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D043263:Myosin-Light-Chain Phosphatase / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism*; D054460:rho-Associated Kinases
D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D018994:Myosin Light Chains; C115635:citron-kinase; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; D043263:Myosin-Light-Chain Phosphatase; D024462:Myosin Type II