Localization and characterization of tubulin-like proteins associated with brain mitochondria: the presence of a membrane-specific isoform.
A mitochondrial fraction, purified from pig brain, was found to contain associated polypeptides with the same electrophoretic migration and isoelectric points as the alpha- and beta-tubulin subunits present in brain microtubules. When analyzed by Western blotting these polypeptides reacted specifically with purified tubulin antibodies. The tubulin-like proteins were then visualized in mitochondrial membranes by protein A-gold complexes after the incubation of purified mitochondria with tubulin antibodies. When membrane and microtubule proteins were compared by isoelectric focussing and two-dimensional gel electrophoresis, differences were observed in the patterns of tubulin isoforms. An additional polypeptide, with the electrophoretic migration of beta-tubulin but the isoelectric point of alpha-tubulin, was found to be enriched in the mitochondrial fraction. This peptide had several Staphylococcus aureus V8 protease peptides in common with alpha-tubulin and may result from a posttranslational modification of that subunit.
D000818:Animals; D001921:Brain / Q000648:ultrastructure*; D004591:Electrophoresis, Polyacrylamide Gel; D007106:Immune Sera / Q000276:immunology; D007425:Intracellular Membranes / Q000648:ultrastructure*; D007525:Isoelectric Focusing; D008854:Microscopy, Electron; D008928:Mitochondria / Q000648:ultrastructure*; D011817:Rabbits / Q000276:immunology; D013552:Swine; D014404:Tubulin / Q000276:immunology / Q000302:isolation & purification*
D007106:Immune Sera; D014404:Tubulin