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Identification of the human mitochondrial protein import receptor, huMas20p. Complementation of Δ mas 20 in yeast
Author(s) -
Swie Goping Ing,
Millar Douglas G.,
Shore Gordon C.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01010-c
Subject(s) - tetratricopeptide , biology , mitochondrion , inner mitochondrial membrane , biochemistry , complementation , microbiology and biotechnology , signal peptide , yeast , fusion protein , protein targeting , saccharomyces cerevisiae , peptide sequence , membrane protein , membrane , gene , phenotype , recombinant dna
The human homolog of the S. cerevisiaelN. crassa mitochondrial protein import receptor, Mas20p/MOM19, has been identified and characterized. Sequence similarities between these three proteins is most pronounced within the NH 2 ‐terminal third of the molecules. However, the mammalian protein exhibits only weak homology to the tetratricopeptide repeat B domain that is found in Mas20p/MOM19. huMas20p is targeted and inserted into the outer membrane of isolated rat heart mitochondria, in the N in ‐C cyto orientation. Antibodies directed against the soluble portion of huMas20p inhibited in vitro mitochondrial import of a diverse set of precursor proteins (including inner membrane uncoupling protein), but failed to block import of a fusion protein bearing the signal‐anchor sequence of Mas20p itself. Finally, expression of huMAS20 complemented the respiratory defect of Δ mas20 yeast cells. Together, these results demonstrate that huMAS20p is a component of the mammalian import apparatus.