NIP1 (BNIP1) is a member of the BCL2/adenovirus E1B 19 kd-interacting protein (BNIP) family. It interacts with the E1B 19 kDa protein which is responsible for the protection of virally-induced cell death, as well as E1B 19 kDa-like sequences of BCL2, also an apoptotic protector. Alternative splicing of this gene results in four products of unknown function. Transcript variant BNIP1 contains the entire coding region of the gene. This variant contains a fully conserved BH3 domain, which has been associated with pro-apoptotic function.