title: LEM2 recruits CHMP7 for ESCRT-mediated nuclear envelope closure in fission yeast and human cells.
abstract: Endosomal sorting complexes required for transport III (ESCRT-III) proteins have been implicated in sealing the nuclear envelope in mammals, spindle pole body dynamics in fission yeast, and surveillance of defective nuclear pore complexes in budding yeast. Here, we report that Lem2p (LEM2), a member of the LEM (Lap2-Emerin-Man1) family of inner nuclear membrane proteins, and the ESCRT-II/ESCRT-III hybrid protein Cmp7p (CHMP7), work together to recruit additional ESCRT-III proteins to holes in the nuclear membrane. InSchizosaccharomyces pombe, deletion of the ATPasevps4leads to severe defects in nuclear morphology and integrity. These phenotypes are suppressed by loss-of-function mutations that arise spontaneously inlem2orcmp7, implying that these proteins may function upstream in the same pathway. Building on these genetic interactions, we explored the role of LEM2 during nuclear envelope reformation in human cells. We found that CHMP7 and LEM2 enrich at the same region of the chromatin disk periphery during this window of cell division and that CHMP7 can bind directly to the C-terminal domain of LEM2 in vitro. We further found that, during nuclear envelope formation, recruitment of the ESCRT factors CHMP7, CHMP2A, and IST1/CHMP8 all depend on LEM2 in human cells. We conclude that Lem2p/LEM2 is a conserved nuclear site-specific adaptor that recruits Cmp7p/CHMP7 and downstream ESCRT factors to the nuclear envelope.
authors.affiliation: Department of Biochemistry, University of Utah, Salt Lake City, UT 84112.|Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158.
authors.forename: Mingyu
authors.initials: M
authors.lastname: Gu
authors.affiliation: Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112.
authors.forename: Dollie
authors.initials: D
authors.lastname: LaJoie
authors.affiliation: Department of Biochemistry, University of Utah, Salt Lake City, UT 84112.
authors.forename: Opal S
authors.initials: OS
authors.lastname: Chen
authors.affiliation: Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158.
authors.forename: Alexander
authors.initials: A
authors.lastname: von Appen
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Ladinsky
authors.affiliation: Health Sciences Center (HSC) Imaging Core Facility, University of Utah, Salt Lake City, UT 84122.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Redd
authors.affiliation: HSC Electron Microscopy Core Facility, University of Utah, Salt Lake City, UT 84122.
authors.forename: Linda
authors.initials: L
authors.lastname: Nikolova
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125.
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: Bjorkman
authors.affiliation: Department of Biochemistry, University of Utah, Salt Lake City, UT 84112; adam.frost@ucsf.edu wes@biochem.utah.edu katharine.ullman@hci.utah.edu.
authors.forename: Wesley I
authors.initials: WI
authors.lastname: Sundquist
authors.affiliation: Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112; adam.frost@ucsf.edu wes@biochem.utah.edu katharine.ullman@hci.utah.edu.
authors.forename: Katharine S
authors.initials: KS
authors.lastname: Ullman
authors.affiliation: Department of Biochemistry, University of Utah, Salt Lake City, UT 84112; adam.frost@ucsf.edu wes@biochem.utah.edu katharine.ullman@hci.utah.edu.|Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158.
authors.forename: Adam
authors.initials: A
authors.lastname: Frost
mesh_terms: D000483:Alleles; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008938:Mitosis / Q000235:genetics; D008954:Models, Biological; D009685:Nuclear Envelope / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010641:Phenotype; D011485:Protein Binding; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D059008:Time-Lapse Imaging
chemical_list: C514910:CHMP7 protein, human; D056827:Endosomal Sorting Complexes Required for Transport; C516121:LEMD2 protein, human; D008565:Membrane Proteins; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins
keywords: CHMP7; ESCRT-III; LEM2; VPS4; nuclear envelope