title: The role of molecular chaperones in protein transport into the mammalian endoplasmic reticulum.
abstract: Molecular chaperones belonging to the Hsp70 protein family play various roles in posttranslational protein transport into the yeast endoplasmic reticulum (ER): (i) Cytosolic Hsp70 (Hsc70) together with the J-domain containing Hsp40 preserves the transport competent state of presecretory proteins; (ii) ER-lumenal Hsp70 (Kar2p or Lhs1p) triggers the initial insertion of precursor proteins into the core of the protein translocase in the ER-membrane and cooperates with a J-domain containing membrane protein (Sec63p); (iii) the ER-lumenal Hsp70 and its membrane receptor also are involved in completion of translocation. Here a working model is presented for the putative roles of molecular chaperones in post- as well as cotranslational protein transport into the mammalian ER.
authors.affiliation: Medizinische Biochemie, Universität des Saarlandes, Homburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Zimmermann
mesh_terms: D000818:Animals; D001692:Biological Transport; D003600:Cytosol / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000201:enzymology / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008954:Models, Biological; D018832:Molecular Chaperones / Q000378:metabolism*; D000069816:SEC Translocation Channels
chemical_list: D008565:Membrane Proteins; D018832:Molecular Chaperones; D000069816:SEC Translocation Channels