Identification of phosphorylation sites on murine nuclear lamin C by RP-HPLC and microsequencing.
Isolated interphase lamin C, obtained from Ehrlich ascites tumor cells, was digested by Lys-C endoproteinase, the resulting peptides separated by reversed-phase HPLC and subjected to microsequencing in order to identify phosphorylation sites in interphase and following phosphorylation in vitro by cdc2-kinase, protein kinase C (PKC) and protein kinase A (PKA), respectively. Nuclear lamin C showed partial phosphorylation of Ser392 and Ser409, and possibly Ser407 in interphase. Phosphorylation was increased in response to cdc2-kinase at Ser390 and Ser392 and to PKC at Ser572. The N-terminal peptide (aa 1-32) containing consensus sequences for the 3 kinases was phosphorylated by cdc2-kinase, PKC and PKA. The sequence data suggests that multiple molecular switches via lamina modification control the dynamic behaviour of the nucleoskeleton during the cell cycle.
Eggert
M
M
Institute of Genetics, Justus-Liebig-University, Giessen, Germany.
Radomski
N
N
Tripier
D
D
Traub
P
P
Jost
E
E
D000595:Amino Acid Sequence; D000818:Animals; D001345:Autoradiography; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D034904:Lamin Type A; D034882:Lamins; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism
D034904:Lamin Type A; D034882:Lamins; D009687:Nuclear Proteins; C440308:lamin C; D011494:Protein Kinases; D011493:Protein Kinase C; D016203:CDC2 Protein Kinase