Intact microtubules are required for rapid turnover of carboxyl-terminal tyrosine of alpha-tubulin in cell cultures.
In cultured muscle cells the carboxyl-terminal tyrosine of alpha-tubulin was shown to exchange rapidly with free tyrosine. The rapid turnover of this residue was dependent upon the presence of intact microtubules. Half-life determinations were made by two methods: (i) the cells were pulse-labeled in hypertonic medium, in which the major tyrosine incorporation was post-translational, and then chased with isotonic medium; and (ii) the cells were pulsed and chased in isotonic medium, and the post-translational component of the radioactivity of purified alpha-tubulin was calculated. Both methods yielded a half-life of 37 min or less for the terminal tyrosine residue, whereas the half-life of tubulin itself was shown to be greater than 48 hr.
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D003078:Colchicine / Q000494:pharmacology; D006023:Glycoproteins / Q000096:biosynthesis*; D007700:Kinetics; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism; D011034:Podophyllotoxin / Q000494:pharmacology; D011312:Pressure; D014404:Tubulin / Q000096:biosynthesis*; D014443:Tyrosine / Q000378:metabolism*; D014747:Vinblastine / Q000494:pharmacology
D006023:Glycoproteins; D014404:Tubulin; D014443:Tyrosine; D014747:Vinblastine; D011034:Podophyllotoxin; D003078:Colchicine