Identification and characterization of microtubule proteins from myxamoebae of Physarum polycephalum.
Cell extracts of myxamoebae of Physarum polycephalum have been prepared in such a way that they do not inhibit assembly of brain microtubule protein in vitro even at high extract-protein concentration. Co-polymers of these extracts and brain tubulin have been purified to constant stoichiometry and amoebal components identified by radiolabelling. Amoebal tubulin has been identified as having an alpha-subunit, mol.wt. 54 000, which co-migrates with brain alpha-tubulin and a beta-subunit, mol.wt. 50 000, which co-migrates with Tetrahymena ciliary beta-tubulin. Non-tubulin amoebal proteins that co-purify with tubulin during co-polymer formation have been shown to be essential for microtubule formation in the absence of glycerol and appear to be rather more effective than brain microtubule-associated proteins in stimulating assembly. The mitotic inhibitor griseofulvin (7-chloro-2',4,6-trimethoxy-6'-methylspiro[benzofuran-2(3H),1'-cyclohex-2'-ene] -3,4'-dione), which binds to brain microtubule-associated proteins and inhibits brain microtubule assembly in vitro, affected co-polymer microtubule protein in a similar way, but to a slightly greater extent.
D000818:Animals; D001704:Biopolymers; D001923:Brain Chemistry; D055598:Chemical Phenomena; D002621:Chemistry; D002852:Chromatography, Ion Exchange; D004121:Dimethyl Sulfoxide; D004591:Electrophoresis, Polyacrylamide Gel; D006118:Griseofulvin / Q000494:pharmacology; D010804:Physarum / Q000032:analysis*; D012756:Sheep; D014404:Tubulin / Q000302:isolation & purification*
D001704:Biopolymers; D014404:Tubulin; D006118:Griseofulvin; D004121:Dimethyl Sulfoxide