ATPase Family, AAA Domain Containing Protein 5 (ATAD5)

FRAG1 contains N-terminal nuclear localization signals, followed by a central region similar to the large subunit of replication factor C (RFC1) in budding yeast, an AAA family motif, and a C-terminal RB-binding motif. It also has 2 ATR phosphorylation sites. Northern blot analysis detected Frag1 expression in all murine cell lines examined.

Reduction of Frag1 with small interfering RNA increased sensitivity to replication stress and gamma irradiation. Cells showed caspase-7 activation and increased Bax protein expression, which was independent of p53 activation. Immunoprecipitation analysis and in vitro pull-down assays indicated that Frag1 interacted with Rad9, and mutation analysis indicated that the RFC-like domain of Frag1 mediated the interaction.