5N5N

Cryo-EM structure of tsA201 cell alpha1B and betaI and betaIVb microtubules

Summary for 5N5N

• Entry DOI: 10.2210/pdb5n5n/pdb
• EMDB information: 3589
• Descriptor: Tubulin beta chain, Tubulin alpha-1B chain, PHOSPHOMETHYLPHOSPHONIC ACID GUANYLATE ESTER, ... (5 entities in total)
• Functional Keywords: microtubules dynamics tubulin isoform, structural protein
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 12
• Total formula weight: 584962.91

Authors

Vemu, A.,Atherton, J.,Spector, J.O.,Moores, C.A.,Roll-Mecak, A. (deposition date: 2017-02-14, release date: 2017-11-01, Last modification date: 2024-05-15)

Primary citation

Vemu, A.,Atherton, J.,Spector, J.O.,Moores, C.A.,Roll-Mecak, A.
Tubulin isoform composition tunes microtubule dynamics.
Mol. Biol. Cell, 28:3564-3572, 2017

PubMed Abstract: Microtubules polymerize and depolymerize stochastically, a behavior essential for cell division, motility, and differentiation. While many studies advanced our understanding of how microtubule-associated proteins tune microtubule dynamics in trans, we have yet to understand how tubulin genetic diversity regulates microtubule functions. The majority of in vitro dynamics studies are performed with tubulin purified from brain tissue. This preparation is not representative of tubulin found in many cell types. Here we report the 4.2-Å cryo-electron microscopy (cryo-EM) structure and in vitro dynamics parameters of α1B/βI+βIVb microtubules assembled from tubulin purified from a human embryonic kidney cell line with isoform composition characteristic of fibroblasts and many immortalized cell lines. We find that these microtubules grow faster and transition to depolymerization less frequently compared with brain microtubules. Cryo-EM reveals that the dynamic ends of α1B/βI+βIVb microtubules are less tapered and that these tubulin heterodimers display lower curvatures. Interestingly, analysis of EB1 distributions at dynamic ends suggests no differences in GTP cap sizes. Last, we show that the addition of recombinant α1A/βIII tubulin, a neuronal isotype overexpressed in many tumors, proportionally tunes the dynamics of α1B/βI+βIVb microtubules. Our study is an important step toward understanding how tubulin isoform composition tunes microtubule dynamics.

PubMed: 29021343
DOI: 10.1091/mbc.E17-02-0124

Experimental method

ELECTRON MICROSCOPY (4.2 Å)