Golgi matrix protein playing a role in tethering of vesicles to Golgi membranes and in maintaining the overall structure of the Golgi apparatus. Interacts with the GTP-bound ARF3/ARL1, but not with the GDP-bound ARF3/ARL1. Locates to the trans-Golgi or to the trans-Golgi network (TGN). The C-terminal GRIP domain (711-788) is necessary and sufficient for Golgi targeting.