Tim9p, an essential partner subunit of Tim10p for the import of mitochondrial carrier proteins

C M Koehler; S Merchant; W Oppliger; K Schmid; E Jarosch; L Dolfini; T Junne; G Schatz; K Tokatlidis

doi:10.1093/emboj/17.22.6477

Tim9p, an essential partner subunit of Tim10p for the import of mitochondrial carrier proteins

EMBO J. 1998 Nov 16;17(22):6477-86. doi: 10.1093/emboj/17.22.6477.

Authors

C M Koehler¹, S Merchant, W Oppliger, K Schmid, E Jarosch, L Dolfini, T Junne, G Schatz, K Tokatlidis

Affiliation

¹ Biochemie, Biozentrum der Universität Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland. koehlerc@ubaclu.unibas.ch

Abstract

Tim10p, a protein of the yeast mitochondrial intermembrane space, was shown previously to be essential for the import of multispanning carrier proteins from the cytoplasm into the inner membrane. We now identify Tim9p, another essential component of this import pathway. Most of Tim9p is associated with Tim10p in a soluble 70 kDa complex. Tim9p and Tim10p co-purify in successive chromatographic fractionations and co-immunoprecipitated with each other. Tim9p can be cross-linked to a partly translocated carrier protein. A small fraction of Tim9p is bound to the outer face of the inner membrane in a 300 kDa complex whose other subunits include Tim54p, Tim22p, Tim12p and Tim10p. The sequence of Tim9p is 25% identical to that of Tim10p and Tim12p. A Ser67-->Cys67 mutation in Tim9p suppresses the temperature-sensitive growth defect of tim10-1 and tim12-1 mutants. Tim9p is a new subunit of the TIM machinery that guides hydrophobic inner membrane proteins across the aqueous intermembrane space.

Publication types

Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Amino Acid Sequence
Biological Transport
Carrier Proteins / chemistry
Carrier Proteins / genetics
Carrier Proteins / metabolism*
Fungal Proteins / genetics
Fungal Proteins / metabolism*
Genes, Suppressor
Intracellular Membranes / metabolism
Membrane Proteins / chemistry
Membrane Proteins / genetics
Membrane Proteins / metabolism*
Membrane Transport Proteins*
Mitochondria / metabolism*
Mitochondrial Membrane Transport Proteins
Mitochondrial Precursor Protein Import Complex Proteins
Mitochondrial Proteins*
Molecular Sequence Data
Point Mutation
Protein Binding
Saccharomyces cerevisiae / genetics
Saccharomyces cerevisiae / metabolism
Saccharomyces cerevisiae Proteins*
Sequence Homology, Amino Acid

Substances

Carrier Proteins
Fungal Proteins
Membrane Proteins
Membrane Transport Proteins
Mitochondrial Membrane Transport Proteins
Mitochondrial Precursor Protein Import Complex Proteins
Mitochondrial Proteins
Saccharomyces cerevisiae Proteins
TIM10 protein, S cerevisiae
Tim9 protein, S cerevisiae

Associated data

GENBANK/AF093244