Tom40 forms the hydrophilic channel of the mitochondrial import pore for preproteins
Autor(en): | Hill, K Model, K Ryan, MT Dietmeier, K Martin, F Wagner, R Pfanner, N |
Stichwörter: | CELL VIABILITY; CONTACT SITES; IDENTIFICATION; MACHINERY; Multidisciplinary Sciences; OUTER-MEMBRANE PROTEIN; PRECURSOR PROTEINS; PRESEQUENCE; RECEPTOR COMPLEX; RECOGNITION; Science & Technology - Other Topics; TRANSLOCATION | Erscheinungsdatum: | 1998 | Herausgeber: | MACMILLAN MAGAZINES LTD | Enthalten in: | NATURE | Band: | 395 | Ausgabe: | 6701 | Startseite: | 516 | Seitenende: | 521 | Zusammenfassung: | The mitochondrial outer membrane contains machinery for the import of preproteins encoded by nuclear genes(1-3). Eight different Tom (translocase of outer membrane) proteins have been identified that function as receptors and/or are related to a hypothetical general import pore. Many mitochondrial membrane channel activities have been described(4-7), including one related to Tim23 of the inner-membrane protein-import system(5); however, the pore-forming subunit(s) of the Tom machinery have not been identified until now. Here we describe the expression and functional reconstitution of Tom40, an integral membrane protein with mainly beta-sheet structure. Tom40 forms a cation-selective high-conductance channel that specifically binds to and transports mitochondrial-targeting sequences added to the cis side of the membrane. We conclude that Tom40 is the pore-forming subunit of the mitochondrial general import pore and that it constitutes a hydrophilic, similar to 22 Angstrom wide channel for the import of preproteins. |
ISSN: | 00280836 | DOI: | 10.1038/26780 |
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geprüft am 06.06.2024