title: Identification and functional analysis of the essential and regulatory light chains of the only type II myosin Myo1p in Saccharomyces cerevisiae.
abstract: Cytokinesis in Saccharomyces cerevisiae involves coordination between actomyosin ring contraction and septum formation and/or targeted membrane deposition. We show that Mlc1p, a light chain for Myo2p (type V myosin) and Iqg1p (IQGAP), is the essential light chain for Myo1p, the only type II myosin in S. cerevisiae. However, disruption or reduction of Mlc1p-Myo1p interaction by deleting the Mlc1p binding site on Myo1p or by a point mutation in MLC1, mlc1-93, did not cause any obvious defect in cytokinesis. In contrast, a different point mutation, mlc1-11, displayed defects in cytokinesis and in interactions with Myo2p and Iqg1p. These data suggest that the major function of the Mlc1p-Myo1p interaction is not to regulate Myo1p activity but that Mlc1p may interact with Myo1p, Iqg1p, and Myo2p to coordinate actin ring formation and targeted membrane deposition during cytokinesis. We also identify Mlc2p as the regulatory light chain for Myo1p and demonstrate its role in Myo1p ring disassembly, a function likely conserved among eukaryotes.
authors.affiliation: Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6058, USA.
authors.forename: Jianying
authors.initials: J
authors.lastname: Luo
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Vallen
authors.forename: Christopher
authors.initials: C
authors.lastname: Dravis
authors.forename: Serguei E
authors.initials: SE
authors.lastname: Tcheperegine
authors.forename: Becky
authors.initials: B
authors.lastname: Drees
authors.forename: Erfei
authors.initials: E
authors.lastname: Bi
mesh_terms: D000205:Actomyosin / Q000502:physiology; D000595:Amino Acid Sequence; D017124:Conserved Sequence; D005838:Genotype; D008969:Molecular Sequence Data; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D018994:Myosin Light Chains / Q000378:metabolism*; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017384:Sequence Deletion
chemical_list: C112936:MYO1 protein, S cerevisiae; D018994:Myosin Light Chains; D029701:Saccharomyces cerevisiae Proteins; D000205:Actomyosin; D018995:Myosin Heavy Chains