Concentration of GPI-anchored proteins upon ER exit in yeast.
Previous biochemical work has revealed two parallel routes of exit from the endoplasmic reticulum (ER) in the yeast Saccharomyces cerevisiae, one seemingly specific for glycosyl-phosphatidylinositol (GPI)-anchored proteins. Using the coat protein II (COPII) mutant sec31-1, we visualized ER exit sites (ERES) and identified three distinct ERES populations in vivo. One contains glycosylated pro-alpha-factor, the second contains the GPI-anchored proteins Cwp2p, Ccw14p and Tos6p and the third is enriched with the hexose transporter, Hxt1p. Concentration of GPI-anchored proteins prior to budding requires anchor remodeling, and Hxt1p incorporation into ERES requires the COPII components Sec12p and Sec16p. Additionally, we have found that GPI-anchored protein ER exit is controlled by the p24 family member Emp24p, whereas ER export of most transmembrane proteins requires the Cornichon homologue Erv14p.
Castillon
Guillaume A
GA
Department of Biochemistry, University of Geneva, Sciences II, 30 quai Ernest Ansermet, CH-1211 Geneva, Switzerland.
Watanabe
Reika
R
Taylor
Marcia
M
Schwabe
Tatjana M E
TM
Riezman
Howard
H
D026905:Amino Acid Transport Systems / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism*; D022162:Cytoplasmic Vesicles / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D051246:Glucose Transport Proteins, Facilitative; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism
D026905:Amino Acid Transport Systems; C105281:CCW14 protein, S cerevisiae; C093811:CWP2 protein, S cerevisiae; C093262:EMP24 protein, S cerevisiae; C493590:Erv14 protein, S cerevisiae; C491145:GAP1 protein, S cerevisiae; D051246:Glucose Transport Proteins, Facilitative; D017261:Glycosylphosphatidylinositols; C090594:HXT1 protein, S cerevisiae; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins