55K isoform of CDK9 associates with Ku70 and is involved in DNA repair.

Article Details

Citation

Liu H, Herrmann CH, Chiang K, Sung TL, Moon SH, Donehower LA, Rice AP

55K isoform of CDK9 associates with Ku70 and is involved in DNA repair.

Biochem Biophys Res Commun. 2010 Jun 25;397(2):245-50. doi: 10.1016/j.bbrc.2010.05.092. Epub 2010 May 20.

PubMed ID
20493174 [ View in PubMed
]
Abstract

Positive elongation factor b (P-TEFb) is a cellular protein kinase that is required for RNA polymerase II (RNAP II) transcriptional elongation of protein coding genes. P-TEFb is a set of different molecular complexes, each containing CDK9 as the catalytic subunit. There are two isoforms of the CDK9 protein - the major 42KDa CDK9 isoform and the minor 55KDa isoform that is translated from an in-frame mRNA that arises from an upstream transcriptional start site. We found that shRNA depletion of the 55K CDK9 protein in HeLa cells induces apoptosis and double-strand DNA breaks (DSBs). The levels of apoptosis and DSBs induced by the depletion were reduced by expression of a 55K CDK9 protein variant resistant to the shRNA, indicating that these phenotypes are the consequence of depletion of the 55K protein and not off-target effects. We also found that the 55K CDK9 protein, but not the 42K CDK9 protein, specifically associates with Ku70, a protein involved in DSB repair. Our findings suggest that the 55K CDK9 protein may function in repair of DNA through an association with Ku70.

DrugBank Data that Cites this Article

Polypeptides
NameUniProt ID
Cyclin-dependent kinase 9P50750Details