title: The nuclear basket proteins Mlp1p and Mlp2p are part of a dynamic interactome including Esc1p and the proteasome.
abstract: The basket of the nuclear pore complex (NPC) is generally depicted as a discrete structure of eight protein filaments that protrude into the nucleoplasm and converge in a ring distal to the NPC. We show that the yeast proteins Mlp1p and Mlp2p are necessary components of the nuclear basket and that they also embed the NPC within a dynamic protein network, whose extended interactome includes the spindle organizer, silencing factors, the proteasome, and key components of messenger ribonucleoproteins (mRNPs). Ultrastructural observations indicate that the basket reduces chromatin crowding around the central transporter of the NPC and might function as a docking site for mRNP during nuclear export. In addition, we show that the Mlps contribute to NPC positioning, nuclear stability, and nuclear envelope morphology. Our results suggest that the Mlps are multifunctional proteins linking the nuclear transport channel to multiple macromolecular complexes involved in the regulation of gene expression and chromatin maintenance.
authors.affiliation: Department of Systems Biology, Harvard Medical School, Boston, MA 02115 Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, Rockefeller University, New York, NY 10065 Laboratory of Cellular and Structural Biology, Rockefeller University, New York, NY 10065 Institute for Research in Biomedicine, 6500 Bellinzona, Switzerland Istituto Cantonale di Microbiologia, 6500 Bellinzona, Switzerland Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605.
authors.forename: Mario
authors.initials: M
authors.lastname: Niepel
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Molloy
authors.forename: Rosemary
authors.initials: R
authors.lastname: Williams
authors.forename: Julia C
authors.initials: JC
authors.lastname: Farr
authors.forename: Anne C
authors.initials: AC
authors.lastname: Meinema
authors.forename: Nicholas
authors.initials: N
authors.lastname: Vecchietti
authors.forename: Ileana M
authors.initials: IM
authors.lastname: Cristea
authors.forename: Brian T
authors.initials: BT
authors.lastname: Chait
authors.forename: Michael P
authors.initials: MP
authors.lastname: Rout
authors.forename: Caterina
authors.initials: C
authors.lastname: Strambio-De-Castillia
mesh_terms: D015966:Gene Expression Regulation, Fungal; D009685:Nuclear Envelope / Q000648:ultrastructure; D022022:Nuclear Pore / Q000235:genetics / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; D012441:Saccharomyces cerevisiae / Q000166:cytology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae / Q000235:genetics; D008941:Spindle Apparatus / Q000235:genetics
chemical_list: C495981:Esc1 protein, S cerevisiae; C080988:MLP1 protein, S cerevisiae; C119200:MLP2 protein, S cerevisiae; D028861:Nuclear Pore Complex Proteins; D009687:Nuclear Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins; C084122:SIR3 protein, S cerevisiae; C061573:SIR4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D038281:Silent Information Regulator Proteins, Saccharomyces cerevisiae; C026452:messenger ribonucleoprotein; D046988:Proteasome Endopeptidase Complex