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Traffic. 2016 Mar;17(3):191-210. doi: 10.1111/tra.12356. Epub 2016 Jan 10.

Analysis of COPII Vesicles Indicates a Role for the Emp47-Ssp120 Complex in Transport of Cell Surface Glycoproteins.

Author information

1
Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA.
2
Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA.
3
Present address: Singer Instruments, Roadwater, Watchet, Somerset, TA23 0RE, UK.

Abstract

Coat protein complex II (COPII) vesicle formation at the endoplasmic reticulum (ER) transports nascent secretory proteins forward to the Golgi complex. To further define the machinery that packages secretory cargo and targets vesicles to Golgi membranes, we performed a comprehensive proteomic analysis of purified COPII vesicles. In addition to previously known proteins, we identified new vesicle proteins including Coy1, Sly41 and Ssp120, which were efficiently packaged into COPII vesicles for trafficking between the ER and Golgi compartments. Further characterization of the putative calcium-binding Ssp120 protein revealed a tight association with Emp47 and in emp47Δ cells Ssp120 was mislocalized and secreted. Genetic analyses demonstrated that EMP47 and SSP120 display identical synthetic positive interactions with IRE1 and synthetic negative interactions with genes involved in cell wall assembly. Our findings support a model in which the Emp47-Ssp120 complex functions in transport of plasma membrane glycoproteins through the early secretory pathway.

KEYWORDS:

COPII coat; Golgi; cargo receptors; endoplasmic reticulum; protein secretion; protein trafficking; vesicle budding

PMID:
26650540
PMCID:
PMC4767645
[Available on 2017-03-01]
DOI:
10.1111/tra.12356
[Indexed for MEDLINE]
Free PMC Article

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