Mutations in Human Tubulin Proximal to the Kinesin-Binding Site Alter Dynamic Instability at Microtubule Plus- and Minus-Ends

Journal Article · Fri Apr 01 04:00:00 EDT 2016 · Developmental Cell

DOI:https://doi.org/10.1016/j.devcel.2016.03.003· OSTI ID:1379273

Ti, Shih-Chieh; Pamula, Melissa C.; Howes, Stuart C.; Duellberg, Christian; Cade, Nicholas I.; Kleiner, Ralph E.; Forth, Scott; Surrey, Thomas; Nogales, Eva; Kapoor, Tarun M.

The assembly of microtubule-based cellular structures depends on regulated tubulin polymerization and directional transport. In this research, we have purified and characterized tubulin heterodimers that have human β-tubulin isotype III (TUBB3), as well as heterodimers with one of two β-tubulin mutations (D417H or R262H). Both point mutations are proximal to the kinesin-binding site and have been linked to an ocular motility disorder in humans. Compared to wild-type, microtubules with these mutations have decreased catastrophe frequencies and increased average lifetimes of plus- and minus-end-stabilizing caps. Importantly, the D417H mutation does not alter microtubule lattice structure or Mal3 binding to growing filaments. Instead, this mutation reduces the affinity of tubulin for TOG domains and colchicine, suggesting that the distribution of tubulin heterodimer conformations is changed. Together, our findings reveal how residues on the surface of microtubules, distal from the GTP-hydrolysis site and inter-subunit contacts, can alter polymerization dynamics at the plus- and minus-ends of microtubules.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: National Institutes of Health
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1379273
• Journal Information: Developmental Cell, Journal Name: Developmental Cell Journal Issue: 1 Vol. 37; ISSN 1534-5807
• Publisher: Cell Press - Elsevier
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES