Low molecular weight microtubule-associated proteins are light chains of microtubule-associated protein 1 (MAP 1).
Microtubule-associated protein 1 (MAP 1; Mr = 350,000) was analyzed by column chromatography of microtubule protein obtained from calf brain gray and white matter. Two low molecular weight proteins (LMW MAPs; Mr 28,000 and 30,000) were found to cochromatograph with MAP 1 under all conditions examined. MAP 1 and the LMW MAPs were purified from calf brain white matter as a complex containing approximately equimolar amounts of the three species. Urea (6 M) was used to remove the LMW MAPs from MAP 1. Binding of MAP 1 to microtubules was unaffected by urea and occurred with or without the LMW species. Electron microscopy of microtubules composed of purified tubulin and either MAP 1 preparation revealed that, like MAP 2, MAP 1 has the appearance of a filamentous arm on the microtubule surface.
D000818:Animals; D001923:Brain Chemistry; D002417:Cattle; D004591:Electrophoresis, Polyacrylamide Gel; D046911:Macromolecular Substances; D008854:Microscopy, Electron; D008869:Microtubule-Associated Proteins; D008870:Microtubules / Q000648:ultrastructure; D008970:Molecular Weight; D011506:Proteins / Q000032:analysis*
D046911:Macromolecular Substances; D008869:Microtubule-Associated Proteins; D011506:Proteins