title: A 3D analysis of yeast ER structure reveals how ER domains are organized by membrane curvature.
abstract: We analyzed the structure of yeast endoplasmic reticulum (ER) during six sequential stages of budding by electron tomography to reveal a three-dimensional portrait of ER organization during inheritance at a nanometer resolution. We have determined the distribution, dimensions, and ribosome densities of structurally distinct but continuous ER domains during multiple stages of budding with and without the tubule-shaping proteins, reticulons (Rtns) and Yop1. In wild-type cells, the peripheral ER contains cytoplasmic cisternae, many tubules, and a large plasma membrane (PM)-associated ER domain that consists of both tubules and fenestrated cisternae. In the absence of Rtn/Yop1, all three domains lose membrane curvature, ER ribosome density changes, and the amount of PM-associated ER increases dramatically. Deletion of Rtns/Yop1 does not, however, prevent bloated ER tubules from being pulled from the mother cisterna into the bud and strongly suggests that Rtns/Yop1 stabilize/maintain rather than generate membrane curvature at all peripheral ER domains in yeast.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
authors.forename: Matt
authors.initials: M
authors.lastname: West
authors.forename: Nesia
authors.initials: N
authors.lastname: Zurek
authors.forename: Andreas
authors.initials: A
authors.lastname: Hoenger
authors.forename: Gia K
authors.initials: GK
authors.lastname: Voeltz
mesh_terms: D055032:Electron Microscope Tomography; D004721:Endoplasmic Reticulum / Q000648:ultrastructure*; D007425:Intracellular Membranes / Q000648:ultrastructure*; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000648:ultrastructure; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D029701:Saccharomyces cerevisiae Proteins; C426246:YOP1 protein, S cerevisiae