Myosin light chain kinase (MLCK) gene disruption in Dictyostelium: a role for MLCK-A in cytokinesis and evidence for multiple MLCKs.
We have created a strain of Dictyostelium that is deficient for the Ca2+/calmodulin-independent MLCK-A. This strain undergoes cytokinesis less efficiently than wild type, which results in an increased frequency of multinucleate cells when grown in suspension. The MLCK-A-cells are able, however, to undergo development and to cap crosslinked surface receptors, processes that require myosin heavy chain. Phosphorylated regulatory light chain (RLC) is still present in MLCK-A-cells, indicating that Dictyostelium has one or more additional protein kinases capable of phosphorylating RLC. Concanavalin A treatment was found to induce phosphorylation of essentially all of the RLC in wild-type cells, but RLC phosphorylation levels in MLCK-A-cells are unaffected by concanavalin A. Thus MLCK-A is regulated separately from the other MLCK(s) in the cell.
Department of Biochemistry, Beckman Center, Stanford University Medical Center, CA 94305-5307, USA.
J L
JL
Smith
L A
LA
Silveira
J A
JA
Spudich
D000818:Animals; D002455:Cell Division; D002460:Cell Line; D003208:Concanavalin A / Q000494:pharmacology; D004023:Dictyostelium / Q000201:enzymology / Q000235:genetics; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D009219:Myosin-Light-Chain Kinase / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation
D007527:Isoenzymes; D003208:Concanavalin A; D009219:Myosin-Light-Chain Kinase