%0 Electronic Article %A Schröder, S and Schimmöller, F and Singer-Krüger, B and Riezman, H %I Rockefeller University Press %D 1995 %D 1995 %G English %@ 0021-9525 %@ 1540-8140 %~ Katalog der Universitätsbibliothek Leipzig %T The Golgi-localization of yeast Emp47p depends on its di-lysine motif but is not affected by the ret1-1 mutation in alpha-COP. %V 131 %J The Journal of cell biology %V 131 %N 4 %P 895-912 %U http://dx.doi.org/10.1083/jcb.131.4.895 %X The Saccharomyces cerevisiae EMP47 gene encodes a nonessential type-I transmembrane protein with sequence homology to a class of intracellular lectins defined by ERGIC-53 and VIP36. The 12-amino acid COOH-terminal cytoplasmic tail of Emp47p ends in the sequence KTKLL, which conforms with the consensus for di-lysine-based ER-localization signals. Despite the presence of this motif, Emp47p was shown to be a Golgi protein at steady-state. The di-lysine motif of Emp47p was functional when transplanted onto Ste2p, a plasma membrane protein, conferring ER localization. Nevertheless, the di-lysine motif was required for Golgi-localization of Emp47p and showed the same charge-independent, position-dependent characteristics of other di-lysine motifs. Alpha-COP has been shown to be required for ER localization of di-lysine-tagged proteins. Consistent with this finding, the Ste2p-Emp47p hybrid protein was mislocalized to the cell surface in the alpha-COP mutant, ret1-1. Surprisingly, the Golgi-localization of Emp47p was unaffected by the ret1-1 mutation. To investigate whether Emp47p undergoes retrograde transport from the Golgi to the ER like other di-lysine-tagged proteins we developed an assay to measure this step after block of forward transport in a sec12 mutant. Under these conditions retrograde transport led to a specific redistribution of Emp47p from the Golgi to the ER. This recycling occurred from a Golgi subcompartment containing alpha 1,3 mannose-modified oligosaccharides suggesting that it originated from a medial-or later Golgi compartment. Thus Emp47p cycles between the Golgi apparatus and the ER and requires a di-lysine motif for its alpha-COP-independent, steady state localization in the Golgi. %Z https://katalog.ub.uni-leipzig.de/Record/ai-49-aHR0cDovL2R4LmRvaS5vcmcvMTAuMTA4My9qY2IuMTMxLjQuODk1 %U https://katalog.ub.uni-leipzig.de/Record/ai-49-aHR0cDovL2R4LmRvaS5vcmcvMTAuMTA4My9qY2IuMTMxLjQuODk1