Title

Yip1A structures the mammalian endoplasmic reticulum.

Date of Original Version

5-1-2010

Type

Article

PubMed ID

20237155

Abstract or Description

The structure of the endoplasmic reticulum (ER) undergoes highly regulated changes in specialized cell types. One frequently observed type of change is its reorganization into stacked and concentrically whorled membranes, but the underlying mechanisms and functional relevance for cargo export are unknown. Here, we identify Yip1A, a conserved membrane protein that cycles between the ER and early Golgi, as a key mediator of ER organization. Yip1A depletion led to restructuring of the network into multiple, micrometer-sized concentric whorls. Membrane stacking and whorl formation coincided with a marked slowing of coat protein (COP)II-mediated protein export. Furthermore, whorl formation driven by exogenous expression of an ER protein with no role in COPII function also delayed cargo export. Thus, the slowing of protein export induced by Yip1A depletion may be attributed to a proximal role for Yip1A in regulating ER network dispersal. The ER network dispersal function of Yip1A was blocked by alteration of a single conserved amino acid (E95K) in its N-terminal cytoplasmic domain. These results reveal a conserved Yip1A-mediated mechanism for ER membrane organization that may serve to regulate cargo exit from the organelle.

DOI

10.1091/mbc.E09-12-1002

 

Published In

Molecular biology of the cell, 21, 9, 1556-1568.