Abstract
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.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Carrier Proteins / genetics
-
Carrier Proteins / metabolism*
-
Cell Wall / metabolism
-
Chitin / metabolism
-
Endoplasmic Reticulum / metabolism*
-
Glycosylphosphatidylinositols / biosynthesis*
-
Guanosine Triphosphate / metabolism
-
Membrane Proteins / genetics
-
Membrane Proteins / metabolism
-
Mutation
-
Saccharomyces cerevisiae / metabolism
-
Saccharomyces cerevisiae Proteins / genetics
-
Saccharomyces cerevisiae Proteins / metabolism*
-
Signal Transduction
-
Uridine Diphosphate N-Acetylglucosamine / metabolism
-
ras Proteins / metabolism*
Substances
-
Carrier Proteins
-
Eri1 protein, S cerevisiae
-
GPI1 protein, S cerevisiae
-
Glycosylphosphatidylinositols
-
Membrane Proteins
-
Saccharomyces cerevisiae Proteins
-
Chitin
-
Uridine Diphosphate N-Acetylglucosamine
-
Guanosine Triphosphate
-
ras Proteins