Post-translational modifications of α-tubulin in Zea mays L. are highly tissue specific

To further understand post-translational modifications (PTMs) of plant α-tubulin, post-translationally modified α-tubulin isoforms from selected tissues of Zea mays L. were examined using two-dimensional electrophoresis and immunoblotting. Except for polyglycylated tubulin, tyrosinated, detyrosinated, acetylated and polyglutamylated α-tubulin isoforms were all present in maize tissues. Tyrosinated α-tubulin was the predominant variant in all cases, with isoforms α1-α4 (α5) being the most common components. Leaves exhibited a striking difference in PTM patterns of α-tubulin isoforms compared to other tissues examined. In leaves, several major specific isoforms were highly modified by detyrosination, acetylation and polyglutamylation. In pollen and anthers, only the most abundant isoform α3 was acetylated to an appreciable extent, and no acetylated isoform was found in roots. Similarly, in pollen, anthers and roots, only α3 was appreciably polyglutamylated. Additionally, a detyrosinated isoform α6 was present in anthers and in leaves, while the tyrosinated isoform α6 seemed to be pollen specific. These results indicate that certain types of PTM of plant α-tubulin preferentially occur in a tissue-specific way.