Data for: Mechanistic insights into TTLL11 polyglutamylase-mediated primary tubulin chain elongation

Microtubules (MTs) undergo diverse posttranslational modifications that
regulate their structural and functional properties. Among these,
polyglutamylation—a dominant and conserved modification targeting
unstructured tubulin C-terminal tails—plays a pivotal role in defining the
tubulin code. Here, we describe a mechanism by which tubulin tyrosine
ligase–like 11 (TTLL11) expands and diversifies the code. Cryo–electron
microscopy revealed a unique bipartite MT recognition strategy wherein
TTLL11 binding and catalytic domains engage adjacent MT protofilaments.
Biochemical and cellular assays identified previously uncharacterized
polyglutamylation patterns, showing that TTLL11 directly extends the
primary polypeptide chains of α-and β-tubulin in vitro, challenging the
prevailing paradigms emphasizing lateral branching. Moreover, cell-based
and in vivo data suggest a cross-talk between polyglutamylation and the
detyrosination/tyrosination cycle likely linked to the TTLL11-mediated
elongation of the primary α-tubulin chain. These findings unveil an
unrecognized layer of complexity within the tubulin code and offer
mechanistic insights into the molecular basis of functional specialization
of MT cytoskeleton.