Levi SK, et al. (2010) The Yeast GRASP Grh1 Colocalizes with COPII and Is Dispensable for Organizing the Secretory Pathway. Traffic 11(9):1168-79
Abstract: In mammalian cells, the "Golgi Reassembly and Stacking Protein" (GRASP) family has been implicated in Golgi stacking, but the broader functions of GRASP proteins are still unclear. The yeast Saccharomyces cerevisiae contains a single nonessential GRASP homolog called Grh1. However, Golgi cisternae in S. cerevisiae are not organized into stacks, so a possible structural role for Grh1 has been difficult to test. Here we examined the localization and function of Grh1 in S. cerevisiae and in the related yeast Pichia pastoris, which has stacked Golgi cisternae. In agreement with earlier studies indicating that Grh1 interacts with COPII vesicle coat proteins, we find that Grh1 colocalizes with COPII at transitional ER (tER) sites in both yeasts. Deletion of P. pastoris Grh1 had no obvious effect on the structure of tER-Golgi units. To test the role of S. cerevisiae Grh1, we exploited the observation that inhibiting ER export in S. cerevisiae generates enlarged tER sites that are often associated with the cis-Golgi. This tER-Golgi association was preserved in the absence of Grh1. The combined data suggest that Grh1 acts early in the secretory pathway but is dispensable for the organization of secretory compartments.
|Status: Published||Type: Journal Article||PubMed ID: 20573068|
Topics addressed in this paper
Number of different genes curated to this paper: 7
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