RAD9A

This gene product is highly similar to Schizosaccharomyces pombe rad9, a cell cycle checkpoint protein required for cell cycle arrest and DNA damage repair. This protein possesses 3' to 5' exonuclease activity, which may contribute to its role in sensing and repairing DNA damage. It forms a checkpoint protein complex with RAD1 and HUS1. This complex is recruited by checkpoint protein RAD17 to the sites of DNA damage, which is thought to be important for triggering the checkpoint-signaling cascade. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Aug 2011]

Full Name

RAD9 Checkpoint Clamp Component A

Function

Component of the 9-1-1 cell-cycle checkpoint response complex that plays a major role in DNA repair. The 9-1-1 complex is recruited to DNA lesion upon damage by the RAD17-replication factor C (RFC) clamp loader complex. Acts then as a sliding clamp platform on DNA for several proteins involved in long-patch base excision repair (LP-BER). The 9-1-1 complex stimulates DNA polymerase beta (POLB) activity by increasing its affinity for the 3'-OH end of the primer-template and stabilizes POLB to those sites where LP-BER proceeds; endonuclease FEN1 cleavage activity on substrates with double, nick, or gap flaps of distinct sequences and lengths; and DNA ligase I (LIG1) on long-patch base excision repair substrates. The 9-1-1 complex is necessary for the recruitment of RHNO1 to sites of double-stranded breaks (DSB) occurring during the S phase. RAD9A possesses 3'->5' double stranded DNA exonuclease activity. Its phosphorylation by PRKCD may be required for the formation of the 9-1-1 complex.

Biological Process

Biological Process cellular response to DNA damage stimulusManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process cellular response to ionizing radiationManual Assertion Based On ExperimentIDA:UniProtKB
Biological Process DNA damage checkpoint signalingManual Assertion Based On ExperimentIMP:UniProtKB
Biological Process DNA repairManual Assertion Based On ExperimentIBA:GO_Central
Biological Process DNA replication checkpoint signalingManual Assertion Based On ExperimentIBA:GO_Central
Biological Process intrinsic apoptotic signaling pathway in response to DNA damageIEA:Ensembl
Biological Process mitotic intra-S DNA damage checkpoint signalingManual Assertion Based On ExperimentIBA:GO_Central
Biological Process positive regulation of intrinsic apoptotic signaling pathway in response to DNA damageIEA:Ensembl

Cellular Location

Nucleus

PTM

Constitutively phosphorylated on serine and threonine amino acids in absence of DNA damage. Hyperphosphorylated by PRKCD and ABL1 upon DNA damage. Its phosphorylation by PRKCD may be required for the formation of the 9-1-1 complex.