Specifically acetylates 'Lys-40' in alpha-tubulin/mec-12 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 the maintenance of touch receptor neurons and possibly other type of neurons involved in locomotion. acetyl-CoA + L-lysyl-[alpha-tubulin] = CoA + H(+) + N(6)-acetyl-L-lysyl-[alpha-tubulin] Expressed solely in touch receptor neurons. Expressed in touch receptors from late embryos to adults. Mutants are partially insensitive to body touch. Belongs to the acetyltransferase ATAT1 family.