Reaction: n ATP + [tubulin]-L-glutamate + n L-glutamate = [tubulin]-(γ-(poly-α-L-glutamyl)-L-glutamyl)-L-glutamate + n ADP + n phosphate (overall reaction)
(1a) ATP + [tubulin]-L-glutamate + L-glutamate = [tubulin]-(γ-L-glutamyl)-L-glutamate + ADP + phosphate
(1b) ATP + [tubulin]-(γ-L-glutamyl)-L-glutamate + L-glutamate = [tubulin]-(α-L-glutamyl-γ-L-glutamyl)-L-glutamate + ADP + phosphate
(1c) n ATP + [tubulin]-(α-L-glutamyl-γ-L-glutamyl)-L-glutamate + n L-glutamate = [tubulin]-(γ-(poly-α-L-glutamyl)-L-glutamyl)-L-glutamate + n ADP + n phosphate
Other name(s): α-tubulin-glutamate ligase; tubulin polyglutamylase; TTLL1 (ambiguous); TTLL5 (ambiguous); TTLL6 (ambiguous)
Systematic name: [tubulin]-L-glutamate:L-glutamate ligase (ADP-forming)
Comments: The eukaryotic tubulin proteins, which polymerize into microtubules, are highly modified by the addition of side-chains. The polyglutamylation reaction catalysed by this group of enzymes consists of two biochemically distinct steps: initiation and elongation. Initiation comprises the formation of an isopeptide bond with the γ-carboxyl group of the glutamate acceptor site in a glutamate-rich C-terminal region of tubulin, whereas elongation consists of the addition of glutamate residues linked by regular peptide bonds to the γ-linked residue. This entry describes enzymes that act on both α- and β-tubulins.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Regnard, C., Audebert, S., Desbruyeres, Denoulet, P. and Edde, B. Tubulin polyglutamylase: partial purification and enzymatic properties. Biochemistry 37 (1998) 8395-8404. [PMID: 9622491]
2. Regnard, C., Desbruyeres, E., Denoulet, P. and Edde, B. Tubulin polyglutamylase: isozymic variants and regulation during the cell cycle in HeLa cells. J. Cell Sci. 112 (1999) 4281-4289. [PMID: 10564646]
3. Westermann, S., Plessmann, U. and Weber, K. Synthetic peptides identify the minimal substrate requirements of tubulin polyglutamylase in side chain elongation. FEBS Lett. 459 (1999) 90-94. [PMID: 10508923]
4. Janke, C., Rogowski, K., Wloga, D., Regnard, C., Kajava, A.V., Strub, J.M., Temurak, N., van Dijk, J., Boucher, D., van Dorsselaer, A., Suryavanshi, S., Gaertig, J. and Edde, B. Tubulin polyglutamylase enzymes are members of the TTL domain protein family. Science 308 (2005) 1758-1762. [PMID: 15890843]
5. van Dijk, J., Rogowski, K., Miro, J., Lacroix, B., Edde, B. and Janke, C. A targeted multienzyme mechanism for selective microtubule polyglutamylation. Mol. Cell 26 (2007) 437-448. [PMID: 17499049]
6. Wloga, D., Rogowski, K., Sharma, N., Van Dijk, J., Janke, C., Edde, B., Bre, M.H., Levilliers, N., Redeker, V., Duan, J., Gorovsky, M.A., Jerka-Dziadosz, M. and Gaertig, J. Glutamylation on α-tubulin is not essential but affects the assembly and functions of a subset of microtubules in Tetrahymena thermophila, Eukaryot Cell 7 (2008) 1362-1372. [PMID: 18586949]
7. van Dijk, J., Miro, J., Strub, J.M., Lacroix, B., van Dorsselaer, A., Edde, B. and Janke, C. Polyglutamylation is a post-translational modification with a broad range of substrates. J. Biol. Chem. 283 (2008) 3915-3922. [PMID: 18045879]