title: Transport of proteins to the mitochondrial intermembrane space: the 'matrix-targeting' and the 'sorting' domains in the cytochrome c1 presequence.
abstract: We reported earlier that the yeast cytochrome c1 presequence (length: 61 amino acids) directs attached proteins to the mitochondrial intermembrane space and that it appears to contain two functional domains: a 'matrix-targeting' domain, and a 'sorting' domain. We have now used gene manipulation together with two different in vivo import assays to map these two domains within the cytochrome c1 presequence. The 'matrix-targeting' domain is contained within the N-terminal 16 residues (or less); by itself, it directs attached proteins to the matrix. The 'sorting' domain extends into the C-terminal 13 residues of the presequence; while it does not mediate intracellular protein transport by itself, it acts together with the preceding 'matrix-targeting' sequence in sorting attached proteins into the intermembrane space. On replacing the authentic 'matrix-targeting' sequence with artificial sequences of different lengths we found that sorting of proteins between the outer membrane and the intermembrane space is not exclusively determined by the length of the N-terminal 'matrix-targeting' sequence.
authors.affiliation: Biocenter, University of Basel, Switzerland.
authors.forename: A P
authors.initials: AP
authors.lastname: van Loon
authors.forename: A W
authors.initials: AW
authors.lastname: Brändli
authors.forename: B
authors.initials: B
authors.lastname: Pesold-Hurt
authors.forename: D
authors.initials: D
authors.lastname: Blank
authors.forename: G
authors.initials: G
authors.lastname: Schatz
mesh_terms: D000818:Animals; D003574:Cytochrome c Group / Q000235:genetics* / Q000378:metabolism; D003575:Cytochromes c1; D004926:Escherichia coli / Q000235:genetics; D005796:Genes; D005800:Genes, Fungal; D005822:Genetic Vectors; D007425:Intracellular Membranes / Q000378:metabolism*; D051379:Mice; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D013367:Submitochondrial Particles / Q000378:metabolism*; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics
chemical_list: D003574:Cytochrome c Group; D011498:Protein Precursors; C043513:cytochrome C1 precursor; D003575:Cytochromes c1; D013762:Tetrahydrofolate Dehydrogenase