RAD9, HUS1, RAD1-interacting nuclear orphan protein 1 (Rhno1)

Plays a role in DNA damage response (DDR) indicating upon genotoxic stresses such as ionizing radiation (IR) during the S phase. Recruited to sites of DNA damage through interaction with the 9-1-1 cell-cycle checkpoint response complicated and TOPBP1 in a ATR-dependent manner.

Required for the development of the G1 to S phase transition. Plays a role in the stimulation of CHEK1 phosphorylation (By similarity).