TRAPPC3 (trafficking protein particle complex 3, also known as Bet3) is a component of TRAPP, a complex involved in the tethering of transport vesicles to the cis-Golgi membrane. There are three TRAPP complexes identified in yeast with distinct roles: TRAPPI in ER-Golgi traffic, TRAPPII in intra-Golgi and endosome-Golgi traffic, and TRAPPIII in autophagy. Recently it has been proposed that at least two complexes exist in mammals. It has also been reported that TRAPPC3 is required for Rabin8 centrosome trafficking and ciliogenesis. Expressed ubiquitously, TRAPPC3 protein is present in both membrane-bound and cytosolic forms.