A J-protein is an essential subunit of the presequence translocase-associated protein import motor of mitochondria.
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.
Truscott
Kaye N
KN
Institut für Biochemie und Molekularbiologie, Universität Freiburg, D-79104 Freiburg, Germany.
Voos
Wolfgang
W
Frazier
Ann E
AE
Lind
Maria
M
Li
Yanfeng
Y
Geissler
Andreas
A
Dudek
Jan
J
Müller
Hanne
H
Sickmann
Albert
A
Meyer
Helmut E
HE
Meisinger
Chris
C
Guiard
Bernard
B
Rehling
Peter
P
Pfanner
Nikolaus
N
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
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