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EBs recognize a nucleotide-dependent structural cap at growing microtubule ends.

Maurer SP, Fourniol FJ, Bohner G, Moores CA, Surrey T - Cell (2012)

Bottom Line: By binding close to the exchangeable GTP-binding site, the CH domain is ideally positioned to sense the microtubule's nucleotide state.The same microtubule-end region is also a stabilizing structural cap protecting the microtubule from depolymerization.This insight supports a common structural link between two important biological phenomena, microtubule dynamic instability and end tracking.

View Article: PubMed Central - PubMed

Affiliation: Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.

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Additional Lateral Contacts Are Observed in the GTPγS Lattice(A) Comparison of the cryo-EM structures of a Mal3-GTPγS microtubule (8.6 Å resolution) and a GDP microtubule stabilized by doublecortin (Fourniol et al., 2010) (DCX; EMDB ID 1788; 8.2 Å resolution) viewed from the microtubule minus end. An extra interprotofilament contact involving β-tubulin helix H3 (dashed circle) is present in the GTPγS microtubule structure but not in the GDP microtubule structure.(B) Close-up views of the GTPγS and GDP microtubule cryo-EM structures described in (A), focused on the area involved in the additional β-tubulin lateral contact. The two cryo-EM maps are displayed with an equivalent threshold, representative of the whole protein complex volume.See also Figure S5 and Movie S1.
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fig6: Additional Lateral Contacts Are Observed in the GTPγS Lattice(A) Comparison of the cryo-EM structures of a Mal3-GTPγS microtubule (8.6 Å resolution) and a GDP microtubule stabilized by doublecortin (Fourniol et al., 2010) (DCX; EMDB ID 1788; 8.2 Å resolution) viewed from the microtubule minus end. An extra interprotofilament contact involving β-tubulin helix H3 (dashed circle) is present in the GTPγS microtubule structure but not in the GDP microtubule structure.(B) Close-up views of the GTPγS and GDP microtubule cryo-EM structures described in (A), focused on the area involved in the additional β-tubulin lateral contact. The two cryo-EM maps are displayed with an equivalent threshold, representative of the whole protein complex volume.See also Figure S5 and Movie S1.

Mentions: The only other protein known to bind to the corner of four tubulin heterodimers is doublecortin, a microtubule-stabilizing protein that is unrelated to EBs (Fourniol et al., 2010). Together, these two proteins define a polymer-specific binding mode characterized by bridging of microtubule protofilaments. Comparison of the subnanometer models of doublecortin bound to GDP microtubules and Mal3143 bound to GTPγS microtubules reveals, however, that the contacts between the corners of the four tubulin monomers and each of these proteins are not identical and, in particular, the contact with the β-tubulin H3 helix appears to be unique to EBs (Figure 6A).


EBs recognize a nucleotide-dependent structural cap at growing microtubule ends.

Maurer SP, Fourniol FJ, Bohner G, Moores CA, Surrey T - Cell (2012)

Additional Lateral Contacts Are Observed in the GTPγS Lattice(A) Comparison of the cryo-EM structures of a Mal3-GTPγS microtubule (8.6 Å resolution) and a GDP microtubule stabilized by doublecortin (Fourniol et al., 2010) (DCX; EMDB ID 1788; 8.2 Å resolution) viewed from the microtubule minus end. An extra interprotofilament contact involving β-tubulin helix H3 (dashed circle) is present in the GTPγS microtubule structure but not in the GDP microtubule structure.(B) Close-up views of the GTPγS and GDP microtubule cryo-EM structures described in (A), focused on the area involved in the additional β-tubulin lateral contact. The two cryo-EM maps are displayed with an equivalent threshold, representative of the whole protein complex volume.See also Figure S5 and Movie S1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3368265&req=5

fig6: Additional Lateral Contacts Are Observed in the GTPγS Lattice(A) Comparison of the cryo-EM structures of a Mal3-GTPγS microtubule (8.6 Å resolution) and a GDP microtubule stabilized by doublecortin (Fourniol et al., 2010) (DCX; EMDB ID 1788; 8.2 Å resolution) viewed from the microtubule minus end. An extra interprotofilament contact involving β-tubulin helix H3 (dashed circle) is present in the GTPγS microtubule structure but not in the GDP microtubule structure.(B) Close-up views of the GTPγS and GDP microtubule cryo-EM structures described in (A), focused on the area involved in the additional β-tubulin lateral contact. The two cryo-EM maps are displayed with an equivalent threshold, representative of the whole protein complex volume.See also Figure S5 and Movie S1.
Mentions: The only other protein known to bind to the corner of four tubulin heterodimers is doublecortin, a microtubule-stabilizing protein that is unrelated to EBs (Fourniol et al., 2010). Together, these two proteins define a polymer-specific binding mode characterized by bridging of microtubule protofilaments. Comparison of the subnanometer models of doublecortin bound to GDP microtubules and Mal3143 bound to GTPγS microtubules reveals, however, that the contacts between the corners of the four tubulin monomers and each of these proteins are not identical and, in particular, the contact with the β-tubulin H3 helix appears to be unique to EBs (Figure 6A).

Bottom Line: By binding close to the exchangeable GTP-binding site, the CH domain is ideally positioned to sense the microtubule's nucleotide state.The same microtubule-end region is also a stabilizing structural cap protecting the microtubule from depolymerization.This insight supports a common structural link between two important biological phenomena, microtubule dynamic instability and end tracking.

View Article: PubMed Central - PubMed

Affiliation: Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London WC2A 3LY, UK.

Show MeSH
Related in: MedlinePlus