Rapid and reversible tubulin tyrosination in human neutrophils stimulated by the chemotactic peptide, fMet‐Leu‐Phe

Abstract

Neutrophil activation by specific stimuli, such as the oligopeptide chemotactic factor fMet-Leu-Phe (fMLF), is associated with an increased 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 fMLF. 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. Previously, we have shown that under conditions of fMLF-stimulated exocytosis there is an increased binding of neutrophil granules to endogenous microtubules. Since neutrophil activation by fMLF is associated with increased tyrosination of alpha-tubulin subunits, we speculated that rapid changes in the levels of tyrosinated tubulin in the microtubules of activated neutrophils might have a role in the regulation of granule-microtubule interactions. When the binding of purified neutrophil granules to reconstituted rat brain microtubules containing approximately 50% tyrosinated tubulin was measured by electron microscopy and compared with granule binding to microtubules that contained no detectable tyrosinated tubulin, granule-microtubule associations were found to be significantly favored by detyrosinated vs. tyrosinated tubulin. These findings indicate that interactions between cytoplasmic granules and microtubules in activated neutrophils may be modulated by rapid changes in the relative content of detyrosinated and tyrosinated tubulin in the microtubule network of the cells.

Tubulin Tail Sequences and Post-translational Modifications Regulate Closure of Mitochondrial Voltage-dependent Anion Channel (VDAC)

“…This evolutionarily ancient post-translational modification of tubulin is usually related to microtubule stability and binding of other proteins to the microtubule (13), although also implicated in rapid shifts during cellular signaling (20,21).…”

Localized Exocytosis of Primary (Lysosomal) Granules During Phagocytosis: Role of Ca2+-Dependent Tyrosine Phosphorylation and Microtubules

“…Also, during ingestion of Chlamydiae, tyrosine phosphorylation of host cell proteins is required to trigger a microtubule-dependent redistribution of the microorganism (51). Of note, phosphorylation of tyrosine residues on tubulin (52), as well as tubulin tyrosination (53), are felt to be important in microtubule remodelling. The linkage between FcR engagement and the activation of these processes, and their precise role in directed exocytosis remain to be defined.…”

A novel myeloid cell marker genes related signature can indicate immune infiltration and predict prognosis of hepatocellular carcinoma: Integrated analysis of bulk and single-cell RNA sequencing

“…4) TUBA1B, encodes the protein of tubulin alpha-1B chain, is the major constituent of microtubules. Study has shown that changes in the relative content of tubulin may regulate neutrophils activation ( Rothwell et al, 1993 ). 5&6) AKR1C3 and AKR1B10 are enzymes that catalyzes redox transformation and play important role in tumor progression ( Penning, 2015 ).…”