The companion of cellulose SYNTHASE 1 controls microtubule dynamics through a Tau-like mechanism to confer salt tolerance in plants

Kesten C1, Wallmann A2, Oschkinat H2 and Persson S1

  1. School of Biosciences, University of Melbourne, Parkville 3010 VIC, Melbourne, Australia.
  2. Leibniz-Forschungsinstitut fur Molekulare Pharmakologie (FMP), NMR-supported Structural Biology, Robert-Rossle-Str. 10, 13125, Berlin, Germany.

Microtubules are filamentous structures necessary for cell division, motility and morphology. Microtubule dynamics are critically regulated by microtubule-associated proteins (MAPs). We outline the molecular mechanism by which the MAP, COMPANION OF CELLULOSE SYNTHASE1 (CC1), controls microtubule-bundling and dynamics in plants under salt stress conditions. CC1 contains an intrinsically disordered N-terminus that joins microtubules through conserved hydrophobic regions at evenly distributed foci. Structural data on the microtubule-bound CC1 N-terminus and mutation studies revealed the regions, and specific amino acids, that contribute to microtubule-binding. The importance of these regions and amino acids was confirmed through in vivo live cell imaging, which also explains how CC1 maintains cellulose synthesis during salt exposure. Surprisingly, the microtubule-binding mechanism of CC1 is remarkably similar to that of the prominent neuropathology-related protein Tau. Hence, we outline how MAP functions have converged during evolution across animal and plant cells.