Mouse prenylated Rab acceptor is a novel Golgi membrane protein

We have cloned a mouse prenylated Rab acceptor (mPRA), which interacts with various Rab proteins in the yeast two-hybrid system. This study investigat ed its intracellular localization and characterized the localization signal . The mPRA. was found to be an integral membrane protein that was localized to the Golgi complex at steady state as determined by confocal fluorescenc e microscopy. With green fluorescent protein attached to the N-terminus of mPRA the fusion protein was expressed in BHK cells and was shown to exhibit the same Golgi localization as the native mPRA Systematic truncations from the N- and C-termini of mPRA revealed that the entire N-terminal half (91 residues) of the protein was dispensable for the Golgi localization. In con trast, deletion of only 5 residues from the C-terminus diminished the Golgi localization of mPRA, leading to its accumulation in the ER. The data indi cate that the C-terminal half (94 residues) of mPRA is necessary and suffic ient for proper folding, ER export, and Golgi localization. The Golgi local ization of mPRA suggests that it may play a role in the structural organiza tion and function of the Golgi complex. (C) 2000 Academic Press.