Functional interaction of Puralpha with the Cdk2 moiety of cyclin A/Cdk2.
Puralpha is a sequence-specific single-stranded nucleic acid-binding protein and a member of the highly conserved Pur family. Puralpha has been shown to colocalize with cyclin A/Cdk2 and to coimmunoprecipitate with cyclin A during S-phase. Here we show that this interaction is mediated by a specific affinity of Puralpha for Cdk2. In pull-down assays GST-Puralpha efficiently binds Cdk2 and Cdk1, binds Cdk4 less efficiently, and does not display binding to Cdk6. Puralpha stimulates several-fold the phosphorylation in vitro of histone H1 by cyclin A/Cdk2, produced from baculovirus constructs. Double chromatin immunoprecipitation using antibodies to Cdk2 and Puralpha reveals that both proteins colocalize in HeLa cells to DNA segments upstream of the c-MYC gene. Pur family member Purgamma colocalizes with Cdk2 to a specific DNA segment in this region.
Liu
Hong
H
Department of Pathology, Mount Sinai School of Medicine, New York, NY 10029, USA.
Barr
Sharon M
SM
Chu
Caryn
C
Kohtz
D Stave
DS
Kinoshita
Yayoi
Y
Johnson
Edward M
EM
D000818:Animals; D001665:Binding Sites; D042846:CDC2-CDC28 Kinases / Q000737:chemistry* / Q000378:metabolism*; D019925:Cyclin A / Q000737:chemistry* / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2; D004247:DNA / Q000737:chemistry* / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D006367:HeLa Cells; D006657:Histones / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D009419:Nerve Tissue Proteins / Q000737:chemistry* / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding
D019925:Cyclin A; D004268:DNA-Binding Proteins; D006657:Histones; D009419:Nerve Tissue Proteins; C121485:Pura protein, mouse; D004247:DNA; D042846:CDC2-CDC28 Kinases; C495894:CDK2 protein, human; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2