title: Polarization of the endoplasmic reticulum by ER-septin tethering.
abstract: Polarization of the plasma membrane (PM) into domains is an important mechanism to compartmentalize cellular activities and to establish cell polarity. Polarization requires formation of diffusion barriers that prevent mixing of proteins between domains. Recent studies have uncovered that the endoplasmic reticulum (ER) of budding yeast and neurons is polarized by diffusion barriers, which in neurons controls glutamate signaling in dendritic spines. The molecular identity of these barriers is currently unknown. Here, we show that a direct interaction between the ER protein Scs2 and the septin Shs1 creates the ER diffusion barrier in yeast. Barrier formation requires Epo1, a novel ER-associated subunit of the polarisome that interacts with Scs2 and Shs1. ER-septin tethering polarizes the ER into separate mother and bud domains, one function of which is to position the spindle in the mother until M phase by confining the spindle capture protein Num1 to the mother ER.
authors.affiliation: Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada.
authors.forename: Jesse T
authors.initials: JT
authors.lastname: Chao
authors.affiliation: Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada.
authors.forename: Andrew K O
authors.initials: AK
authors.lastname: Wong
authors.affiliation: Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada.
authors.forename: Shabnam
authors.initials: S
authors.lastname: Tavassoli
authors.affiliation: Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada.
authors.forename: Barry P
authors.initials: BP
authors.lastname: Young
authors.affiliation: Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada.
authors.forename: Adam
authors.initials: A
authors.lastname: Chruscicki
authors.affiliation: Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada; Centre for High-Throughput Biology, University of British Columbia, 2125 East Mall, Vancouver BC V6T 1Z4, Canada.
authors.forename: Nancy N
authors.initials: NN
authors.lastname: Fang
authors.affiliation: Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada.
authors.forename: LeAnn J
authors.initials: LJ
authors.lastname: Howe
authors.affiliation: Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada; Centre for High-Throughput Biology, University of British Columbia, 2125 East Mall, Vancouver BC V6T 1Z4, Canada.
authors.forename: Thibault
authors.initials: T
authors.lastname: Mayor
authors.affiliation: Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada; Centre for High-Throughput Biology, University of British Columbia, 2125 East Mall, Vancouver BC V6T 1Z4, Canada.
authors.forename: Leonard J
authors.initials: LJ
authors.lastname: Foster
authors.affiliation: Department of Cellular and Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver BC V6T 1Z3, Canada. Electronic address: cloewen@mail.ubc.ca.
authors.forename: Christopher J R
authors.initials: CJ
authors.lastname: Loewen
mesh_terms: D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D016764:Cell Polarity; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004058:Diffusion; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009685:Nuclear Envelope / Q000378:metabolism; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; C000594941:Epo1 protein, S cerevisiae; C477782:IST2 protein, S cerevisiae; D008565:Membrane Proteins; C071961:NUM1 protein, S cerevisiae; C115656:SHS1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C501314:Scs2 protein, S cerevisiae