Rapid and Reversible Tubulin Tyrosination in Human Neutrophils Stimulated by theChemotacted Peptide, fMet Leu-Phe

摘要

Neutrophil activation by specific stimuli, such as the oligopeptide chemotacticfactor fMet-Leu-Phe (fMLF), is associated with an increasing enzymatic addition of tyrosine to tubulin alpha-subunits, as measured by 14C tyrosine uptake. In studies using immunoblots we have found that this increased tyrosine uptake into tubulin in activated neutrophils reflects an increase in the proportion of cellular tubulin that is tyrosinated rather than simply an increase in the turnover of tyrosinated subunits. However, the increased accumulation of tyrosinated tubulin was also found to follow an initial depletion of tyrosinated tubulin and concomitant increase in detyrosinated tubulin between 0 and 60 sec following stimulation of neutrophils with fMLP. Immunogold electron microscopy studies of intact microtubules recovered from activated neutrophils demonstrated that these rapid changes in the relative content of tubulin isoforms in the cells were not associated with the formation or disappearance of microtubule microdomains composed of only one form of tubulin.