DNA-dependent protein kinase在細胞有絲分裂的功能(2/3)

Abstract

Proteins of the poly(ADP-ribose) polymerase (PARP) family play wide array of functions, covering virtually every aspect of DNA metabolism and function, most notably with the response to DNA damage, transcription and the maintenance of genomic stability. Here we report the identification and characterization of a novel PARP family member, PARP10 (FLJ14464 or hypothetical protein LOC84875). Over-expression of PARP10 results in loss of cell viability, while knockdown by siRNA leads to delayed G1 progression and concomitant cell death. PARP10 exists in both cytoplasm and nucleus, only that in nucleolus is specifically phosphorylated by Cdk through late-G1 to S phase. In an in vitro assay, the enzymatic activity of PARP10 depends on the Cdk phosphorylation. The phosphorylation is shut down in G2, and re-appeared from prometaphase to cytokinesis in the nucleolar organizing regions. The phosphoryated PARP10 is completely absent in growth-arrested cells and may serve as a marker for proliferating cells. These results suggest that PARP10 functions in cell proliferation.