The product of the ATRIP gene is an essential component of the DNA damage checkpoint, and binds to single stranded DNA coated with replication protein A that accumulates at sites of DNA damage. The encoded protein interacts with the ataxia telangiectasia and Rad3 related protein, a checkpoint kinase, resulting in accumulation of the kinase at intranuclear foci induced by DNA damage. Multiple transcript variants encoding different isoforms have been found for this gene.