Yeast Ras regulates the complex that catalyzes the first step in GPI-anchor biosynthesis at the ER.

The yeast ERI1 gene encodes a small ER-localized protein that associates in vivo with GTP bound Ras2 in an effector loop-dependent manner. We showed previously that loss of Eri1 function results in hyperactive Ras phenotypes. Here, we demonstrate that Eri1 is a component of the GPI-GlcNAc transferase (GPI-GnT) complex in ...
the ER, which catalyzes transfer of GlcNAc from UDP-GlcNAc to an acceptor phosphatidylinositol, the first step in the production of GPI-anchors for cell surface proteins. We also show that GTP bound Ras2 associates with the GPI-GnT complex in vivo and inhibits its activity, indicating that yeast Ras uses the ER as a signaling platform from which to negatively regulate the GPI-GnT. We propose that diminished GPI-anchor protein production contributes to hyperactive Ras phenotypes.
Mesh Terms:
Carrier Proteins, Cell Wall, Chitin, Endoplasmic Reticulum, Glycosylphosphatidylinositols, Guanosine Triphosphate, Membrane Proteins, Mutation, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins, Signal Transduction, Uridine Diphosphate N-Acetylglucosamine, ras Proteins
Cell
Date: May. 28, 2004
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