ER cargo properties specify a requirement for COPII coat rigidity mediated by Sec13p.
Eukaryotic secretory proteins exit the endoplasmic reticulum (ER) via transport vesicles generated by the essential coat protein complex II (COPII) proteins. The outer coat complex, Sec13-Sec31, forms a scaffold that is thought to enforce curvature. By exploiting yeast bypass-of-sec-thirteen (bst) mutants, where Sec13p is dispensable, we probed the relationship between a compromised COPII coat and the cellular context in which it could still function. Genetic and biochemical analyses suggested that Sec13p was required to generate vesicles from membranes that contained asymmetrically distributed cargoes that were likely to confer opposing curvature. Thus, Sec13p may rigidify the COPII cage and increase its membrane-bending capacity; this function could be bypassed when a bst mutation renders the membrane more deformable.
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Alenka
A
Copic
Catherine F
CF
Latham
Max A
MA
Horlbeck
Jennifer G
JG
D'Arcangelo
Elizabeth A
EA
Miller
D020816:Amino Acid Motifs; D022181:COP-Coated Vesicles / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005800:Genes, Fungal; D008954:Models, Biological; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D009154:Mutation; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000378:metabolism
D050505:Mutant Proteins; D028861:Nuclear Pore Complex Proteins; C079620:SEC13 protein, S cerevisiae; C106113:SEC31 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins