- Tubulin polyglutamylase enzymes are members of the TTL domain protein family. 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., Eddé, B. Science (2005)