A J-protein is an essential subunit of the presequence translocase–associated protein import motor of mitochondria Academic Article uri icon


  • 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
  • Voos, Wolfgang
  • Frazier, Ann E
  • Lind, Maria
  • Li, Yanfeng
  • Geissler, Andreas
  • Dudek, Jan
  • Müller, Hanne
  • Sickmann, Albert
  • Meyer, Helmut E
  • Meisinger, Chris
  • Guiard, Bernard
  • Rehling, Peter
  • Pfanner, Nikolaus

publication date

  • November 24, 2003

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