Traffic of p24 Proteins and COPII Coat Composition Mutually Influence Membrane Scaffolding.
Eukaryotic protein secretion requires efficient and accurate delivery of diverse secretory and membrane proteins. This process initiates in the ER, where vesicles are sculpted by the essential COPII coat. The Sec13p subunit of the COPII coat contributes to membrane scaffolding, which enforces curvature on the nascent vesicle. A requirement for Sec13p can be bypassed when traffic of lumenally oriented membrane proteins is abrogated. Here we sought to further explore the impact of cargo proteins on vesicle formation. We show that efficient ER export of the p24 family of proteins is a major driver of the requirement for Sec13p. The scaffolding burden presented by the p24 complex is met in part by the cargo adaptor Lst1p, which binds to a subset of cargo, including the p24 proteins. We propose that the scaffolding function of Lst1p is required to generate vesicles that can accommodate difficult cargo proteins that include large oligomeric assemblies and asymmetrically distributed membrane proteins. Vesicles that contain such cargoes are also more dependent on scaffolding by Sec13p, and may serve as a model for large carrier formation in other systems.
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Jennifer G
JG
D'Arcangelo
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Jonathan
J
Crissman
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Silvere
S
Pagant
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Alenka
A
Čopič
Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
Catherine F
CF
Latham
Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Erik L
EL
Snapp
Department of Biological Sciences, Columbia University, New York, NY 10027, USA. Electronic address: em2282@columbia.edu.
Elizabeth A
EA
Miller
D000595:Amino Acid Sequence; D022181:COP-Coated Vesicles / Q000737:chemistry* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism
C093262:EMP24 protein, S cerevisiae; C493590:Erv14 protein, S cerevisiae; C432391:Erv29 protein, S cerevisiae; C066709:GAS1 protein, S cerevisiae; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D028861:Nuclear Pore Complex Proteins; C079620:SEC13 protein, S cerevisiae; C118289:SEC24 protein, S cerevisiae; C120079:SFB3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins