TTL Gene: Tubulin Tyrosine Ligase - Function, Mutations, and Disease Associations

The TTL gene encodes tubulin tyrosine ligase, an enzyme that catalyzes the post-translational addition of a tyrosine residue to the C-terminal end of detyrosinated alpha-tubulin. This reaction is part of the tubulin tyrosination/detyrosination cycle, which regulates microtubule stability, dynamics, and interactions with microtubule-associated proteins. TTL is essential for neuronal development, cell division, and ciliary function. Loss of TTL function leads to abnormal microtubule detyrosination and has been implicated in neurodegenerative disorders and cancer.

Tissue Expression

Cell Line Expression

Hotspot Mutations

Mutation functional classification

• REACTOME: R-HSA-389977 - Post-translational modification of tubulin

• REACTOME: R-HSA-6811434 - COPI-dependent Golgi-to-ER retrograde traffic

• KEGG: hsa04540 - Gap junction

Tubulin tyrosine ligase (TTL) is a 42 kDa cytoplasmic enzyme that catalyzes the ATP-dependent addition of a tyrosine residue to the C-terminal glutamic acid of detyrosinated alpha-tubulin. This reaction is essential for maintaining the tyrosination/detyrosination cycle of microtubules. TTL is highly expressed in the brain and testis, and its activity is critical for proper neuronal migration, axon guidance, and cell division. Loss of TTL function leads to increased detyrosinated tubulin, which alters microtubule dynamics and has been linked to microcephaly, intellectual disability, and cancer progression.