A 205 kDa protein from non-neuronal cells in culture contains tubulin binding epitopes.
Microtubule-associated proteins (MAPs) interact with tubulin in vitro and in vivo. Despite that there is a large amount of information on the roles of these proteins in neurons, the data on non-neuronal MAPs or MAPs-related proteins is scarce. There is an increasing number of microtubule-interacting proteins that have been identified in different cultured cell lines, and some of them share common functional epitopes with the most well-known MAPs, MAP-2 and tau. In a search for tubulin-interacting proteins in non-neuronal cells we identified a 205 kDa protein in the monkey kidney Vero cells in culture, on the basis of immunological studies and affinity chromatography. This protein interacts with the C-terminal moiety of beta-tubulin and cosediments with taxol assembled microtubules, but it was not recovered after successive cycles of assembly and disassembly. The presence of neuronal MAPs such as MAP-1, MAP-2 and tau was not detected in these cells. Interestingly, the studies showed that the 205 kDa protein contained a tubulin binding motif which was recognized by site-directed antibodies that also tag tubulin binding epitopes on MAP-2 and tau. This characteristic led us to designate this protein as MBD-205, a component that shares binding domains with these MAPs, rather than as a marker of the MAPs family. On the other hand, immunofluorescence experiments using site-specific antibodies, i.e. MAP-reacting monoclonal anti-idiotypic reagent MTB6.22 and a polyclonal antibody to the second tau repeat, revealed a MBD-205 co-localization with membrane structures and microtubule-organizing centers in Vero cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Vial
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International Center for Cancer and Developmental Biology (ICC), University of Chile, Santiago.
Armas-Portela
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Avila
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González
M
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Maccioni
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RB
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D015153:Blotting, Western; D002522:Chlorocebus aethiops; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000302:isolation & purification* / Q000502:physiology; D008870:Microtubules / Q000648:ultrastructure; D008969:Molecular Sequence Data; D015739:Nocodazole / Q000494:pharmacology; D010446:Peptide Fragments / Q000276:immunology; D011485:Protein Binding; D011817:Rabbits; D014404:Tubulin / Q000276:immunology / Q000378:metabolism*; D014709:Vero Cells / Q000737:chemistry* / Q000378:metabolism; D016875:tau Proteins / Q000276:immunology
D000906:Antibodies; D000939:Epitopes; C094844:MBD-205 protein, Cercopithecus aethiops; D008869:Microtubule-Associated Proteins; D010446:Peptide Fragments; D014404:Tubulin; D016875:tau Proteins; D015739:Nocodazole