Flagellar microtubule doublet assembly in vitro reveals a regulatory role of tubulin C-terminal tails

Assembly of the ciliary microtubule doublet

The cilium is a conserved organelle that is crucial for motility as well as for sensing the extracellular environment. Its core structure is characterized by nine microtubule doublets (MTDs). The mechanisms of MTD assembly are unclear. Schmidt-Cernohorska et al. developed an assay to reconstitute MTD assembly in vitro. Tubulin carboxyl-terminal tails played a critical inhibitory role in MTD formation. Molecular dynamics revealed that carboxyl-terminal tails of the A11 microtubule protofilament regulated MTD initiation. Furthermore, live-cell imaging showed an unexpected bidirectional isotropic elongation of the MTD.

Science , this issue p. 285