Mitosis-specific phosphorylation of vimentin by protein kinase C coupled with reorganization of intracellular membranes.
Using two types of anti-phosphopeptide antibodies which specifically recognize vimentin phosphorylated by protein kinase C (PKC) at two distinct PKC sites, we found that PKC acted as a mitotic vimentin kinase. Temporal change of vimentin phosphorylation by PKC differed form changes by cdc2 kinase. The mitosis-specific vimentin phosphorylation by PKC was dramatically enhanced by treatment with a PKC activator, 12-O-tetradecanoylphorbol-13-acetate (TPA), while no phosphorylation of vimentin by PKC was observed in interphase cells treated with TPA. By contrast, the disruption of subcellular compartmentalization of interphase cells led to vimentin phosphorylation by PKC. Cytoplasmic and nuclear membranes are fragmented and dispersed in the cytoplasm and some bind to vimentin during mitosis. Thus, targeting of activated PKC, coupled with the reorganization of intracellular membranes which contain phospholipids essential for activation, leads to the mitosis-specific phosphorylation of vimentin. We propose that during mitosis, PKC may phosphorylate an additional subset of proteins not phosphorylated in interphase.
Takai
Y
Y
Department of Neurophysiology, Tokyo Metropolitan Institute of Gerontology, Japan.
Ogawara
M
M
Tomono
Y
Y
Moritoh
C
C
Imajoh-Ohmi
S
S
Tsutsumi
O
O
Taketani
Y
Y
Inagaki
M
M
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001254:Astrocytoma; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002417:Cattle; D002451:Cell Compartmentation; D002455:Cell Division; D002460:Cell Line; D004789:Enzyme Activation; D006801:Humans; D007399:Interphase; D007425:Intracellular Membranes / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000502:physiology; D010748:Phosphopeptides / Q000032:analysis; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014746:Vimentin / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D010743:Phospholipids; D010748:Phosphopeptides; D014746:Vimentin; D011493:Protein Kinase C; D016203:CDC2 Protein Kinase; D013755:Tetradecanoylphorbol Acetate