The polytopic mitochondrial inner membrane proteins MIM17 and MIM23 operate at the same preprotein import site.
Three proteins of the mitochondrial inner membrane are known that are essential for the viability of yeast and seem to be involved in import of preproteins; the integral membrane proteins MIM17 and MIM23 and the peripheral membrane protein MIM44, MIM17 and MIM23 are homologous to each other in their hydrophobic domain, expose their termini to the intermembrane space, and span the inner membrane up to four times, each. A preprotein in transit across the mitochondrial membrane is specifically cross-linked to MIM17, MIM23, MIM44, and matrix hsp70. We conclude that MIM17 and MIM23 are integral parts of a preprotein translocation channel and cooperate with MIM44 and hsp70 at the same protein import site.
Kübrich
M
M
Biochemisches Institut, Universität Freiburg, Germany.
Keil
P
P
Rassow
J
J
Dekker
P J
PJ
Blom
J
J
Meijer
M
M
Pfanner
N
N
D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D002352:Carrier Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000235:genetics; D012097:Repressor Proteins; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; D004271:DNA, Fungal; D005656:Fungal Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011498:Protein Precursors; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C091191:TIM17 protein, S cerevisiae; C083081:TIM23 protein, S cerevisiae