[5][6][7] It is often called SLAM-associated protein (symbol SAP), where "SLAM" refers to signaling lymphocytic activation molecules.

It is a SH2 domain–containing molecule (part of a family of such molecules) that plays a role in SLAM signaling.

A putative function is as an adaptor for Fyn and competitor of phosphatases, leading to modulation of SLAM family function.

SAP has been implicated in autoimmunity,[8] and a mutation of it is associated with X-linked lymphoproliferative disease.

At least 32 disease-causing mutations in this gene have been discovered.