title: A J-protein is an essential subunit of the presequence translocase-associated protein import motor of mitochondria.
abstract: Transport of preproteins into the mitochondrial matrix is mediated by the presequence translocase-associated motor (PAM). Three essential subunits of the motor are known: mitochondrial Hsp70 (mtHsp70); the peripheral membrane protein Tim44; and the nucleotide exchange factor Mge1. We have identified the fourth essential subunit of the PAM, an essential inner membrane protein of 18 kD with a J-domain that stimulates the ATPase activity of mtHsp70. The novel J-protein (encoded by PAM18/YLR008c/TIM14) is required for the interaction of mtHsp70 with Tim44 and protein translocation into the matrix. We conclude that the reaction cycle of the PAM of mitochondria involves an essential J-protein.
authors.affiliation: Institut für Biochemie und Molekularbiologie, Universität Freiburg, D-79104 Freiburg, Germany.
authors.forename: Kaye N
authors.initials: KN
authors.lastname: Truscott
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Voos
authors.forename: Ann E
authors.initials: AE
authors.lastname: Frazier
authors.forename: Maria
authors.initials: M
authors.lastname: Lind
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Li
authors.forename: Andreas
authors.initials: A
authors.lastname: Geissler
authors.forename: Jan
authors.initials: J
authors.lastname: Dudek
authors.forename: Hanne
authors.initials: H
authors.lastname: Müller
authors.forename: Albert
authors.initials: A
authors.lastname: Sickmann
authors.forename: Helmut E
authors.initials: HE
authors.lastname: Meyer
authors.forename: Chris
authors.initials: C
authors.lastname: Meisinger
authors.forename: Bernard
authors.initials: B
authors.lastname: Guiard
authors.forename: Peter
authors.initials: P
authors.lastname: Rehling
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Pfanner
mesh_terms: D000595:Amino Acid Sequence / Q000235:genetics; D001483:Base Sequence / Q000235:genetics; D002352:Carrier Proteins / Q000378:metabolism; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000032:analysis / Q000235:genetics; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D018832:Molecular Chaperones; D020409:Molecular Motor Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D021381:Protein Transport / Q000502:physiology*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D018076:DNA, Complementary; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C086039:MGE1 protein, S cerevisiae; D046911:Macromolecular Substances; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D018832:Molecular Chaperones; D020409:Molecular Motor Proteins; C480348:PAM18 J protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C077016:TIM44 protein, S cerevisiae