This gene encodes a protein that contains a domain with homology to the ancient conserved region of the archain 1 gene and a domain that may be involved in binding ubiquitin-conjugating enzymes. The protein encoded by this gene has been shown to bind to the conserved membrane-proximal sequence of the cytoplasmic tail of integrin alpha(IIb) subunits. These subunits play a crucial role in the integrin alpha(IIb)beta(3) inside-out signalling in platelets and megakaryocytes that leads to platelet aggregation and thrombus formation. This gene overlaps the gene for mitochondrial serine protease 25.