αTAT1 is the major α-tubulin acetyltransferase in mice

Abstract

Post-translational modification of tubulin serves as a powerful means for rapidly adjusting the functional diversity of microtubules. Acetylation of the e-amino group of K40 in a-tubulin is one such modification that is highly conserved in ciliated organisms. Recently, aTAT1, a Gcn5-related N-acetyltransferase, was identified as an a-tubulin acetyltransferase in Tetrahymena and C. elegans. Here we generate mice with a targeted deletion of Atat1 to determine its function in mammals. Remarkably, we observe a loss of detectable K40 a-tubulin acetylation in these mice across multiple tissues and in cellular structures such as cilia and axons where acetylation is normally enriched. Mice are viable and develop normally, however, the absence of Atat1 impacts upon sperm motility and male mouse fertility, and increases microtubule stability. Thus, aTAT1 has a conserved function as the major a-tubulin acetyltransferase in ciliated organisms and has an important role in regulating subcellular specialization of subsets of microtubules.

Tubulin acetylation: responsible enzymes, biological functions and human diseases

“…Wild-type a-tubulin but not the mutant is acetylated by ATAT1, confirming that Lys-40 is the only acetylation site [48]. In a related study, a panacetyl-lysine antibody was used to detect tubulin purified from the Atat1-deficient mouse brain and almost no positive signals were detected [50], supporting that ATAT1 is a major a-tubulin acetyltransferase and Lys-40 is the predominant acetylation site in vivo.…”

“…They possess intrinsic a-tubulin acetyltransferase activity [47,48]. Moreover, ATAT1 functions as a bona-fide tubulin acetyltransferase in vivo, because deletion of the mouse gene leads to nearly complete loss of tubulin acetylation in embryos and various tissues [49][50][51]. Thus, ATAT1 is now considered as a major tubulin acetyltransferase in mammals.…”

“…In addition to catalyzing tubulin acetylation, ATAT1 interacts with microtubule-associated proteins such as doublecortin [49] and destabilizes microtubules independent of its acetyltransferase activity [50].…”

Mechanism of microtubule lumen entry for the α-tubulin acetyltransferase enzyme αTAT1

“…The primary enzyme that is responsible for α-tubulin Lys40 acetylation in mammals, nematodes, and protozoa has been identified as α-tubulin acetyltransferase 1 (αTAT1), which was first found in Tetrahymena and Caenorhabditis elegans (12)(13)(14). However, despite identification of the enzyme and its substrate, the mechanism for how αTAT1 enters the microtubule lumen to access its acetylation sites is yet to be fully understood.…”

Contrasting patterns of evolutionary constraint and novelty revealed by comparative sperm proteomic analysis

“…Tubulin is a well-known substrate for acetylation, including the highly-conserved 382 acetylation of N-terminus Lysine 40 of alphaTub84B. This modification is essential for normal sperm 383 development, morphology and motility in mice [57]. A similar analysis in Manduca identified 111 384 acetylated peptides within 63 proteins.…”