title: Proliferating cell nuclear antigen and p21 are components of multiple cell cycle kinase complexes.
abstract: We have recently shown that two proteins, proliferating cell nuclear antigen (PCNA) and p21, are associated with cyclin D. Here we show that PCNA and p21 are common components of a wide variety of cyclin/cyclin-dependent kinase complexes in nontransformed cells. These include kinase complexes containing cyclin A, cyclin B, and cyclin D, associated either with CDC2, CDK2, CDK4, or CDK5. We show that PCNA and p21 form separate quaternary complex with each cyclin/CDK and that these quaternary complexes contain a substantial, if not major, fraction of the cell cycle kinases in asynchronously growing cells. These results suggest that PCNA and p21 may perform a common function for all these kinases.
authors.affiliation: Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724.
authors.forename: H
authors.initials: H
authors.lastname: Zhang
authors.forename: Y
authors.initials: Y
authors.lastname: Xiong
authors.forename: D
authors.initials: D
authors.lastname: Beach
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000032:analysis; D001345:Autoradiography; D015153:Blotting, Western; D016203:CDC2 Protein Kinase / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000032:analysis* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008715:Methionine / Q000378:metabolism; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000032:analysis*; D018809:Proliferating Cell Nuclear Antigen; D011494:Protein Kinases / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D013462:Sulfur Radioisotopes
chemical_list: D001324:Autoantigens; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D013462:Sulfur Radioisotopes; D008715:Methionine; D011494:Protein Kinases; D016203:CDC2 Protein Kinase