A family of proteins, the GGAs (Golgi-localized, g-adaptin ear-containing, ARF-binding proteins) sequences that showed significant homology to the carboxy-terminal 'ear' domain of g-adaptin. Members of the GGA family (GGA1,GGA2 (also known as VEAR or VHS domain and ear domain of g-adaptin) and GGA3) are ubiquitous coat proteins that facilitate the trafficking of proteins between the trans-Golgi network and the lysosome. However, unlike g-adaptin, the GGAs are not associated with clathrin-coated vesicles or with any of the components of the AP-1 complex. GGA1 and GGA2 are also not associated with each other, although they colocalize on perinuclear membranes. GGA2 shares 45% amino acid sequence identity with GGA1 and 35% with GGA3. In addition to being involved in heterotypic vesicle/suborganelle interactions associated with the Golgi complex, GGA2 may have a tissue-specific function and is highly expressed in kidney, muscle and heart. Furthermore, the VHS domain of GGA2 binds to the acidic cluster-di-leucine motif in the cytoplasmic tail of the cation-independent mannose 6-phosphate receptor (CI-MPR) and this is important for lysosomal enzyme targeting.