AP-1 complex subunit gamma-like 2 (AP1G2) is an 87-kDa protein that is similar to gamma-adaptin (AP1G1), a large chain of the AP1 clathrin-associated adaptor complex, both in primary structure (60% amino acid identity) and domain organisation (Takatsu et al. 1998). AP1G2 can be viewed as a putative endosomal sorting and trafficking adaptor that is specifically required for degradative endocytic trafficking and may help in maintaining homeostasis of the multivesicular body (MVB) protein-sorting pathway. AP1G2 specifically interacts with the core ESCRT subunits hepatocyte growth factor-regulated tyrosine kinase substrate (HGS, aka HRS) and charged multivesicular body protein 2a (CHMP2A aka hVps2-1), involved in MVB processing (Doring et al. 2010).
AP1G2 is also able to bind the large envelope protein (surface protein S) of the hepatitis B virus (HBV), a protein that plays an important role in viral budding (Hartmann-Stuhler & Prange 2001). Disruption of this binding can inhibit virus production (Rost et al. 2006). Thus, AP1G2 may play a role in L-mediated processes of viral biogenesis or pathogenesis.