Identification and characterization of microtubule proteins from myxamoebae of Physarum polycephalum

Biochem J. 1980 Aug 1;189(2):305-12. doi: 10.1042/bj1890305.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biopolymers
  • Brain Chemistry
  • Chemical Phenomena
  • Chemistry
  • Chromatography, Ion Exchange
  • Dimethyl Sulfoxide
  • Electrophoresis, Polyacrylamide Gel
  • Griseofulvin / pharmacology
  • Physarum / analysis*
  • Sheep
  • Tubulin / isolation & purification*


  • Biopolymers
  • Tubulin
  • Griseofulvin
  • Dimethyl Sulfoxide