Transitional endoplasmic reticulum ATPase
double-strand break repair
VCP, a weak ATPase involved in multiple cellular events, interacts physically with BRCA1 in the nucleus of living cells.
BRCA1, a breast/ovarian cancer susceptibility gene, undergoes mutations in as many as 50% of familial breast tumors. Recent studies indicate that BRCA1 may be involved in DNA damage repair. Here, we demonstrate that the BRCA1 protein physically associates with valosin-containing protein (VCP), a member of the ATPases associated with a variety of cellular activities (AAA) superfamily. In vitro studies revealed that VCP, via its N- terminal region, binds to amino acid residues 303-625 in the BRCA1 protein. Although found predominantly in the cytoplasm and, less abundantly, in the nucleus, VCP can be translocated from the nucleus after stimulation with epidermal growth factor. Collectively, our results suggest that VCP, by binding to BRCA1, participates in the DNA damage-repair function as an ATP transporter, possibly facilitating the transcription-coupled repair.