6BJC

TPX2_mini decorated GMPCPP-microtubule

Summary for 6BJC

• Entry DOI: 10.2210/pdb6bjc/pdb
• EMDB information: 7101 7102
• Descriptor: Tubulin alpha-1B chain, Tubulin beta chain, Targeting protein for Xklp2, ... (6 entities in total)
• Functional Keywords: mitosis, gangtp, nucleation, cell cycle
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 14
• Total formula weight: 778853.93

Authors

Zhang, R.,Nogales, E. (deposition date: 2017-11-05, release date: 2017-11-22, Last modification date: 2024-03-13)

Primary citation

Zhang, R.,Roostalu, J.,Surrey, T.,Nogales, E.
Structural insight into TPX2-stimulated microtubule assembly.
Elife, 6:-, 2017

PubMed Abstract: During mitosis and meiosis, microtubule (MT) assembly is locally upregulated by the chromatin-dependent Ran-GTP pathway. One of its key targets is the MT-associated spindle assembly factor TPX2. The molecular mechanism of how TPX2 stimulates MT assembly remains unknown because structural information about the interaction of TPX2 with MTs is lacking. Here, we determine the cryo-electron microscopy structure of a central region of TPX2 bound to the MT surface. TPX2 uses two flexibly linked elements ('ridge' and 'wedge') in a novel interaction mode to simultaneously bind across longitudinal and lateral tubulin interfaces. These MT-interacting elements overlap with the binding site of importins on TPX2. Fluorescence microscopy-based in vitro reconstitution assays reveal that this interaction mode is critical for MT binding and facilitates MT nucleation. Together, our results suggest a molecular mechanism of how the Ran-GTP gradient can regulate TPX2-dependent MT formation.

PubMed: 29120325
DOI: 10.7554/eLife.30959

Experimental method

ELECTRON MICROSCOPY (3.3 Å)