Tim23 links the inner and outer mitochondrial membranes.
Tim23, a key component of the mitochondrial preprotein translocase, is anchored in the inner membrane by its C-terminal domain and exposes an intermediate domain in the intermembrane space that functions as a presequence receptor. We show that the N-terminal domain of Tim23 is exposed on the surface of the outer membrane. The two-membrane-spanning topology of Tim23 is a novel characteristic in membrane biology. By the simultaneous integration into two membranes, Tim23 forms contacts between the outer and inner mitochondrial membranes. Tethering the inner membrane translocase to the outer membrane facilitates the transfer of precursor proteins from the TOM complex to the TIM23 complex and increases the efficiency of protein import.
Donzeau
M
M
Institut für Physiologische Chemie der Universität München, Germany.
Káldi
K
K
Adam
A
A
Paschen
S
S
Wanner
G
G
Guiard
B
B
Bauer
M F
MF
Neupert
W
W
Brunner
M
M
D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism* / Q000648:ultrastructure; D008565:Membrane Proteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism* / Q000648:ultrastructure; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011817:Rabbits; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins
D002352:Carrier Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D029701:Saccharomyces cerevisiae Proteins; C083081:TIM23 protein, S cerevisiae