PT  - JOURNAL ARTICLE
AU  - Yin-Wei Kuo
AU  - Mohammed Mahamdeh
AU  - Yazgan Tuna
AU  - Jonathon Howard
TI  - The force required to remove tubulin from the microtubule lattice
AID  - 10.1101/2022.03.28.486117
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.03.28.486117
4099  - http://biorxiv.org/content/early/2022/03/29/2022.03.28.486117.short
4100  - http://biorxiv.org/content/early/2022/03/29/2022.03.28.486117.full
AB  - Severing enzymes and molecular motors extract tubulin from the walls of microtubules by exerting mechanical force on subunits buried in the lattice. However, how much force is needed to remove tubulin from microtubules is unknown, as is the pathway by which subunits are removed. Using a site-specific functionalization method, we applied forces to the C-terminus of α-tubulin with an optical tweezer and found that a force of ∼30 pN is required to extract tubulin from the microtubule wall. Consistent with this force, we show that several kinesins can also extract tubulin. Additionally, we discovered that partial unfolding is an intermediate step in tubulin removal. The unfolding and extraction forces are similar to those generated by AAA-unfoldases, suggesting that severing proteins such as spastin and katanin use an unfoldase mechanism. Our results reveal the response of tubulin to mechanical force and advance our understanding of severing enzymes and microtubule stability.Competing Interest StatementThe authors have declared no competing interest.