Protein import into yeast mitochondria is inhibited by antibodies raised against 45-kd proteins of the outer membrane.
Import of several precursor proteins into isolated yeast mitochondria is inhibited by rabbit antiserum raised against the total mitochondrial outer membrane or against electrophoretically purified 45-kd outer membrane proteins. Antisera against other outer membrane proteins are only marginally active or inactive. Inhibition by the antiserum against 45-kd proteins is only weak with untreated mitochondria, but reaches 80-90% with mitochondria that had been pretreated with 0.1 mg/ml trypsin. This trypsin pretreatment by itself inhibits precursor import only slightly (30-50%). Selective inhibition of import does not correlate with binding of the various IgGs to the mitochondrial surface and is also observed with the corresponding Fab fragments. Inhibition by antibodies against 45-kd outer membrane proteins strongly suggests the existence of a mitochondrial surface protein mediating protein import and offers a means of isolating this protein.
Ohba
M
M
Biocenter, University of Basel, Switzerland.
Schatz
G
G
D000936:Antigen-Antibody Complex; D001692:Biological Transport; D005656:Fungal Proteins / Q000302:isolation & purification / Q000378:metabolism*; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D007425:Intracellular Membranes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins; D008928:Mitochondria / Q000276:immunology / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008970:Molecular Weight; D011506:Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000276:immunology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014357:Trypsin / Q000494:pharmacology
D000936:Antigen-Antibody Complex; D005656:Fungal Proteins; D007140:Immunoglobulin Fab Fragments; D007074:Immunoglobulin G; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; C489039:TOM70 protein, S cerevisiae; D014357:Trypsin