Tom40, the import channel of the mitochondrial outer membrane, plays an active role in sorting imported proteins
Open Access
- 15 May 2003
- journal article
- research article
- Published by Springer Nature in The EMBO Journal
- Vol. 22 (10) , 2380-2386
- https://doi.org/10.1093/emboj/cdg229
Abstract
The Translocase of the Outer Mitochondrial membrane (TOM complex) is centred on a channel, created by Tom40, serving as the only means of entry for proteins into the mitochondrion. Proteins destined for internal mitochondrial compartments interact subsequently with one of the two distinct protein Translocases of the Inner Mitochondrial membrane (TIM23 and TIM54 complexes) or follow specialized paths into the intermembrane space. To investigate the sorting of precursor proteins to these various sub‐mitochondrial compartments, we created a library of tom40 mutants and screened for alleles selectively corrupt in protein sorting. One of the tom40 mutants, tom40–97 , carries a single point mutation (W243R) resulting in an ineffective transfer of precursors to the TIM23 complex. There is no defect on transfer of precursors to the TIM54 complex or insertion of proteins into the outer membrane. The Tom40 channel is not a passive pore, but plays an active role in protein sorting for all sub‐mitochondrial locations.Keywords
This publication has 50 references indexed in Scilit:
- The protein import motor of mitochondriaNature Reviews Molecular Cell Biology, 2002
- Sensitivity of Single Membrane-Spanning α-Helical Peptides to Hydrophobic Mismatch with a Lipid Bilayer: Effects on Backbone Structure, Orientation, and Extent of Membrane IncorporationBiochemistry, 2001
- The Aromatic Residues Trp and Phe Have Different Effects on the Positioning of a Transmembrane Helix in the Microsomal MembraneBiochemistry, 1999
- Positively and negatively charged residues have different effects on the position in the membrane of a model transmembrane helixJournal of Molecular Biology, 1998
- A Toxic Fusion Protein Accumulating between the Mitochondrial Membranes Inhibits Protein Assembly in VivoPublished by Elsevier ,1998
- The Import Route of ADP/ATP Carrier into Mitochondria Separates from the General Import Pathway of Cleavable Preproteins at thetrans Side of the Outer MembranePublished by Elsevier ,1998
- Characterization and modeling of membrane proteins using sequence analysisCurrent Opinion in Structural Biology, 1995
- Incomplete arrest in the outer membrane sorts NADH-cytochrome b5 reductase to two different submitochondrial compartmentsCell, 1994
- A yeast mitochondrial outer membrane protein essential for protein import and cell viabilityNature, 1990
- A 42K outer-membrane protein is a component of the yeast mitochondrial protein import siteNature, 1989