Open AccessMechanism of microtubule stabilization by taccalonolide AJ
Author(s) -
Yuxi Wang,
Yamei Yu,
Guo Bo Li,
Shu Ang Li,
Chengyong Wu,
B. Gigant,
Wenming Qin,
Hao Chen,
Yangping Wu,
Qiang Chen,
Jinliang Yang
Publication year - 2017
Publication title -
nature communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.559
H-Index - 365
ISSN - 2041-1723
DOI - 10.1038/ncomms15787
Subject(s) - tubulin , microtubule , gtp' , cytoskeleton , binding site , nucleotide , guanosine diphosphate , taxane , biophysics , chemistry , microtubule associated protein , microtubule polymerization , biology , biochemistry , microbiology and biotechnology , guanosine triphosphate , enzyme , cancer , cell , genetics , breast cancer , gene
As a major component of the cytoskeleton, microtubules consist of αβ-tubulin heterodimers and have been recognized as attractive targets for cancer chemotherapy. Microtubule-stabilizing agents (MSAs) promote polymerization of tubulin and stabilize the polymer, preventing depolymerization. The molecular mechanisms by which MSAs stabilize microtubules remain elusive. Here we report a 2.05 Å crystal structure of tubulin complexed with taccalonolide AJ, a newly identified taxane-site MSA. Taccalonolide AJ covalently binds to β-tubulin D226. On AJ binding, the M-loop undergoes a conformational shift to facilitate tubulin polymerization. In this tubulin–AJ complex, the E-site of tubulin is occupied by GTP rather than GDP. Biochemical analyses confirm that AJ inhibits the hydrolysis of the E-site GTP. Thus, we propose that the β-tubulin E-site is locked into a GTP-preferred status by AJ binding. Our results provide experimental evidence for the connection between MSA binding and tubulin nucleotide state, and will help design new MSAs to overcome taxane resistance.