AIP1 (ASK-interacting protein 1), also known as DAB2IP (DAB2 interacting protein), is a 1,189 amino acid protein that localizes to both the membrane and the cytoplasm and contains one Ras-GAP domain, one PH domain and one C2 domain. Expressed at low levels in prostate tissue, AIP1 functions as a Ras GTPase-activating protein that interacts with ASK 1 and, via this interaction, disrupts the association of ASK 1 with an inhibitory 14-3-3 complex, thereby allowing free ASK 1 to function within the cell. AIP1 exists as multiple alternatively spliced isoforms and is down-regulated in prostate cancer tissue, suggesting a role in tumor suppression. Chromosomal aberrations in the gene encoding AIP1 are associated with acute myeloid leukemia (AML), implicating a role for AIP1 fusion proteins in tumorigenesis.