Protein kinase A- and protein kinase C-regulated interaction of plectin with lamin B and vimentin.
Solid-phase binding assays with protein species purified from cultured rat glioma C6 cells and Ehrlich ascites revealed that plectin bound specifically to lamin B but not to lamins A and C. Lamin B interaction was significantly decreased upon in vitro phosphorylation of either lamin B or plectin with protein kinase A or C. In contrast, phosphorylation of plectin with kinase A increased its binding to vimentin, suggesting a different regulation of plectin interactions by this kinase. 32P-radiolabeling of rat glioma C6 cells revealed plectin as a major in vivo target of protein kinase A and protein kinase C. Plectin, present in lysates of dibutyryladenosine 3',5'-cyclic monophosphate-treated cells, showed a 2.5 times higher binding affinity to vimentin than plectin from phorbol ester-treated cells. Furthermore, the relative amounts of plectin in 1% Triton X-100/high salt-insoluble cell fractions decreased to one-fourth of control values upon treating cells with phorbol esters, whereas vimentin was unaffected. This finding suggested a protein kinase C-dependent weakening of plectin interaction with intermediate filaments in vivo. Taken together, these results point to a role of plectin in interlinking cytoskeletal and nuclear elements and suggest that specific protein kinases are involved in regulating these interactions.
Foisner
R
R
Institute of Biochemistry, University of Vienna, Austria.
Traub
P
P
Wiche
G
G
D000818:Animals; D015153:Blotting, Western; D066298:In Vitro Techniques; D007381:Intermediate Filament Proteins; D007382:Intermediate Filaments / Q000378:metabolism; D034921:Lamin Type B; D034882:Lamins; D009685:Nuclear Envelope / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D051190:Plectin; D011485:Protein Binding; D011493:Protein Kinase C / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D014746:Vimentin / Q000378:metabolism*
D007381:Intermediate Filament Proteins; D034921:Lamin Type B; D034882:Lamins; D009687:Nuclear Proteins; C495334:Plec protein, rat; D051190:Plectin; D011506:Proteins; D014746:Vimentin; D011494:Protein Kinases; D011493:Protein Kinase C