The function of ENSG00000137343 (ATAT1, alpha tubulin acetyltransferase 1) is as follows. Specifically acetylates 'Lys-40' in alpha-tubulin on the lumenal side of microtubules. Promotes microtubule destabilization and accelerates microtubule dynamics; this activity may be independent of acetylation activity. Acetylates alpha-tubulin with a slow enzymatic rate, due to a catalytic site that is not optimized for acetyl transfer. Enters the microtubule through each end and diffuses quickly throughout the lumen of microtubules. Acetylates only long/old microtubules because of its slow acetylation rate since it does not have time to act on dynamically unstable microtubules before the enzyme is released. Required for normal sperm flagellar function. Promotes directional cell locomotion and chemotaxis, through AP2A2-dependent acetylation of alpha-tubulin at clathrin-coated pits that are concentrated at the leading edge of migrating cells. May facilitate primary cilium assembly. {ECO:0000255|HAMAP-Rule:MF_03130, ECO:0000269|PubMed:20829795, ECO:0000269|PubMed:21068373, ECO:0000269|PubMed:24097348, ECO:0000269|PubMed:24906155}.