Heterogeneity of cold-stable and cold-labile tubulin in axon- and soma-enriched portions of the adult mouse brain.
Microtubules from the optic nerve (axonal tubulin) and lateral geniculate nucleus (cell tubulin) were separated by cold treatment and the cold-soluble fraction was purified in the presence of Taxol. Isoforms of cold-stable and cold-soluble tubulin were resolved by the use of high-resolution isoelectric focusing. The cold-soluble fraction of axonal tubulin has only 14 of the 20 isotypes seen in the same fraction of cell tubulin. The two cold-stable fractions have 20 isotypes but axonal tubulin has a specific pattern of isotypes 1, 2 and 5. Cold-stable fractions of both axonal and cell tubulin display the existence of an intensely stained alpha-isotype, isotype 7, which seems associated with the property of cold stability. Our results highly favor the hypothesis of a physiological role of the heterogeneity of tubulin in neuronal microtubules.
D000818:Animals; D001369:Axons / Q000032:analysis*; D001921:Brain / Q000166:cytology; D001923:Brain Chemistry; D003080:Cold Temperature; D007525:Isoelectric Focusing; D051379:Mice; D014404:Tubulin / Q000032:analysis*
D014404:Tubulin