Mia40, a novel factor for protein import into the intermembrane space of mitochondria is able to bind metal ions.
Many proteins located in the intermembrane space (IMS) of mitochondria are characterized by a low molecular mass, contain highly conserved cysteine residues and coordinate metal ions. Studies on one of these proteins, Tim13, revealed that net translocation across the outer membrane is driven by metal-dependent folding in the IMS . We have identified an essential component, Mia40/Tim40/Ykl195w, with a highly conserved domain in the IMS that is able to bind zinc and copper ions. In cells lacking Mia40, the endogenous levels of Tim13 and other metal-binding IMS proteins are strongly reduced due to the impaired import of these proteins. Furthermore, Mia40 directly interacts with newly imported Tim13 protein. We conclude that Mia40 is the first essential component of a specific translocation pathway of metal-binding IMS proteins.
Terziyska
Nadia
N
Adolf-Butenandt-Institut für Physiologische Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5, D-81377 München, Germany.
Lutz
Thomas
T
Kozany
Christian
C
Mokranjac
Dejana
D
Mesecke
Nikola
N
Neupert
Walter
W
Herrmann
Johannes M
JM
Hell
Kai
K
D000595:Amino Acid Sequence / Q000235:genetics; D002457:Cell Extracts / Q000737:chemistry; D017124:Conserved Sequence / Q000235:genetics; D003300:Copper / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D007477:Ions / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008969:Molecular Sequence Data; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D017384:Sequence Deletion / Q000235:genetics; D015032:Zinc / Q000378:metabolism
D002457:Cell Extracts; D007477:Ions; C495320:MIA40 protein, S cerevisiae; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D029701:Saccharomyces cerevisiae Proteins; C403093:TIM13 protein, S cerevisiae; D003300:Copper; D015032:Zinc