Adaptor protein complex AP-1, gamma subunit The adaptor protein complexes mediate both the recruitment of clathrin to membranes and the recognition of sorting signals within the cytosolic tails of transmembrane cargo molecules. Adaptor protein complex 1 (AP-1) is a heterotetramer composed of two large adaptins (gamma-type subunit AP1G1 and beta-type subunit AP1B1), a medium adaptin (mu-type subunit AP1M1 or AP1M2) and a small adaptin (sigma-type subunit AP1S1 or AP1S2 or AP1S3). Subunits of clathrin-associated adaptor protein complex 1 play a role in protein sorting in the late-Golgi/trans-Golgi network (TGN) and/or in endosomes.<p>This group represents an adaptor protein complex AP-1, gamma subunit.</p>