Protein kinase Cgamma regulates myosin IIB phosphorylation, cellular localization, and filament assembly.
Nonmuscle myosin II is an important component of the cytoskeleton, playing a major role in cell motility and chemotaxis. We have previously demonstrated that, on stimulation with epidermal growth factor (EGF), nonmuscle myosin heavy chain II-B (NMHC-IIB) undergoes a transient phosphorylation correlating with its cellular localization. We also showed that members of the PKC family are involved in this phosphorylation. Here we demonstrate that of the two conventional PKC isoforms expressed by prostate cancer cells, PKCbetaII and PKCgamma, PKCgamma directly phosphorylates NMHC-IIB. Overexpression of wild-type and kinase dead dominant negative PKCgamma result in both altered NMHC-IIB phosphorylation and subcellular localization. We have also mapped the phosphorylation sites of PKCgamma on NMHC-IIB. Conversion of the PKCgamma phosphorylation sites to alanine residues, reduces the EGF-dependent NMHC-IIB phosphorylation. Aspartate substitution of these sites reduces NMHC-IIB localization into cytoskeleton. These results indicate that PKCgamma regulates NMHC-IIB phosphorylation and cellular localization in response to EGF stimulation.
Rosenberg
Michael
M
Department of Biochemistry, Institute of Medical Sciences, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel.
Ravid
Shoshana
S
D000205:Actomyosin / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D019556:COS Cells; D016764:Cell Polarity / Q000187:drug effects; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects; D015870:Gene Expression; D006801:Humans; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D018995:Myosin Heavy Chains / Q000737:chemistry / Q000378:metabolism*; D024501:Nonmuscle Myosin Type IIB / Q000737:chemistry / Q000378:metabolism*; D010449:Peptide Mapping; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D011993:Recombinant Fusion Proteins; D001224:Aspartic Acid; D004815:Epidermal Growth Factor; D000205:Actomyosin; C087857:protein kinase C gamma; D011493:Protein Kinase C; D024501:Nonmuscle Myosin Type IIB; C103815:nonmuscle myosin type IIB heavy chain; D018995:Myosin Heavy Chains