Tubulin Tyrosine Ligase (TTL)

TTL is a cytosolic enzyme involved in the posttranslational modification of alpha-tubulin. Alpha-tubulin within assembled microtubules is detyrosinated over time at the C terminus. After microtubule disassembly, TTL restores the tyrosine residues and consequently participates in a cycle of tubulin detyrosination and tyrosination

By searching a database for sequences similar to mouse Ttl, followed by RT-PCR of HeLa cell total RNA, Erck et al. (2003) cloned human TTL. The deduced 377-amino acid protein contains conserved amino acids that form an ATP-Mg(2+)-binding site. TTL shares more than 90% amino acid identity with mouse, pig, rat, and bovine Ttl. Northern blot analysis detected a TTL transcript of about 6.0 kb.