Component Of Oligomeric Golgi Complex 3 (COG3)

COG3 has similarity to a yeast protein. It seems to be part of a peripheral membrane protein complex localized on cis/medial Golgi cisternae where it may participate in tethering intra-Golgi transport vesicles.The deduced 828-amino acid protein, which is 41% similar to the yeast protein, contains a conserved N-terminal coiled-coil domain and a putative leucine zipper motif but no transmembrane sequence. Northern blot analysis revealed abundant and ubiquitous expression of a 4.5-kb transcript, with the highest level in pancreas and testis and the lowest level in lung. Immunoblot analysis showed expression of a 94-kD Golgi membrane protein, the same size as predicted from the primary sequence. Immunofluorescence microscopy demonstrated colocalization with the Golgi SNAP receptor, membrin (GOSR2).