Incorporation of 3-nitrotyrosine into the C-terminus of alpha-tubulin is reversible and not detrimental to dividing cells

BISIG CG, PURRO SA, CONTÍN MA, BARRA HS, ARCE CA

EUROPEAN JOURNAL OF BIOCHEMISTRY

Año: 2002 vol. OCT p. 5037 - 5037

0014-2956

he C-terminus of the alpha-chain of tubulin is subject to reversible incorporation of tyrosine by tubulin tyrosine ligase and removal by tubulin carboxypeptidase. Thus, microtubules rich in either tyrosinated or detyrosinated tubulin can coexist in the cell. Substitution of the terminal tyrosine by 3-nitrotyrosine has been claimed to cause microtubule dysfunction and consequent injury of epithelial lung carcinoma A549 cells. Nitrotyrosine is formed in cells by nitration of tyrosine by nitric oxide-derived species. We studied properties of tubulin modified by in vitro nitrotyrosination at the C-terminus of the alpha-subunit, and the consequences for cell functioning. Nitrotyrosinated tubulin was a good substrate of tubulin carboxypeptidase, and showed a similar capability to assemble into microtubules in vitro to that of tyrosinated tubulin. Tubulin of C6 cells cultured in F12K medium in the presence of 500 micro m nitrotyrosine became fully nitrotyrosinated. This nitroty