A TOG:αβ-tubulin Complex Structure Reveals Conformation-Based Mechanisms for a Microtubule Polymerase

Ayaz, Pelin; Ye, Xuecheng; Huddleston, Patrick; Brautigam, Chad A.; Rice, Luke M.

doi:10.1126/science.1221698

Cited by 227 publications

(336 citation statements)

References 33 publications

(43 reference statements)

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“…In both cases, detached from tubulin, these sequestering proteins are intrinsically unfolded (35,47). In addition, several proteins, such as tubulin tyrosine ligase (48) and TOG domains (49), inhibit microtubule assembly in a dosedependent manner. Both proteins are folded on their own.…”

Section: Discussionmentioning

confidence: 99%

Biochemical and Structural Insights into Microtubule Perturbation by CopN from Chlamydia pneumoniae

Nawrotek

Guimarães

Velours

et al. 2014

Journal of Biological Chemistry

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Background: Although parasites commonly hijack the actin cytoskeleton, the Chlamydia pneumoniae CopN protein interferes with microtubules. Results: CopN targets the ␤-tubulin longitudinal interface and inhibits microtubule assembly through a dual mechanism. Conclusion: In addition to regulating type III secretion, C. pneumoniae CopN has evolved microtubule-related specific functions. Significance: A framework for understanding the CopN role in the chlamydial infectious cycle is provided.

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Section: Discussionmentioning

confidence: 99%

Biochemical and Structural Insights into Microtubule Perturbation by CopN from Chlamydia pneumoniae

Nawrotek

Guimarães

Velours

et al. 2014

Journal of Biological Chemistry

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“…An argument against this mechanism is that XMAP215 is attached to the bead via its C terminus, yet the polymerase activity is primarily due to the first two TOG domains, located at the N terminus (16); thus, the effect on these TOG domains of forces exerted through the bead will be diminished if the intervening three TOG domains (and the basic domain) bind to the microtubule. The specific model of Ayaz et al (44) proposes that the most-N-terminal TOG domain (TOG1) catalyzes subunit incorporation, whereas TOG2 helps to maintain attachment to the microtubule end; a tensile force applied through the C terminus would not be expected to accelerate polymerization in this model. For this reason, we prefer the diffusion mechanism; although because the spatial arrangement of the TOG domains at the microtubule end is not known for sure, the possibility that tensile force increases υ max cannot, at present, be excluded.…”

Section: Discussionmentioning

confidence: 99%

The growth speed of microtubules with XMAP215-coated beads coupled to their ends is increased by tensile force

Trushko

Schäffer

Howard

2013

Proc. Natl. Acad. Sci. U.S.A.

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The generation of pulling and pushing forces is one of the important functions of microtubules, which are dynamic and polarized structures. The ends of dynamic microtubules are able to form relatively stable links to cellular structures, so that when a microtubule grows it can exert a pushing force and when it shrinks it can exert a pulling force. Microtubule growth and shrinkage are tightly regulated by microtubule-associated proteins (MAPs) that bind to microtubule ends. Given their localization, MAPs may be exposed to compressive and tensile forces. The effect of such forces on MAP function, however, is poorly understood. Here we show that beads coated with the microtubule polymerizing protein XMAP215, the Xenopus homolog of Dis1 and chTOG, are able to link stably to the plus ends of microtubules, even when the ends are growing or shrinking; at growing ends, the beads increase the polymerization rate. Using optical tweezers, we found that tensile force further increased the microtubule polymerization rate. These results show that physical forces can regulate the activity of MAPs. Furthermore, our results show that XMAP215 can be used as a handle to sense and mechanically manipulate the dynamics of the microtubule tip.microtubule polymerase | microtubule dynamics | optical trap X MAP215 is a microtubule plus-end binding protein that alters microtubule dynamics (1-4) by promoting microtubule growth. It was identified as a factor increasing microtubule polymerization rates in Xenopus egg extracts (5). In vivo studies have shown that disruption of XMAP215 function leads to short interphase microtubules, reduced microtubule growth rate, and increased frequency of microtubule catastrophe and pause events (6-11). Depletion of XMAP215 also results in short, abnormally formed mitotic spindles and short astral microtubules (7,12,13). In vitro studies have demonstrated that XMAP215 binds preferentially to the microtubule plus end and follows the growth and shrinkage of the microtubule tip, catalyzing microtubule growth (14-16). In addition to localization at the microtubule plus end and centrosomes (17-19), proteins of the XMAP215/Dis1 family are found at the kinetochores (9, 20, 21), which are sites of high force during cell division. Microtubules themselves can exert pulling and pushing forces (22)(23)(24)(25)(26)(27)(28)(29)(30). Therefore, the localization of XMAP215 at microtubule ends suggests that XMAP215 can function under load. However, the effect of forces on XMAP215 activity has not been directly analyzed. In this study, we investigated the influence of forces-directed toward the microtubule plus and minus end-on XMAP215 activity in vitro. Microtubule growth and shrinkage were monitored with high spatial and temporal resolution by visualizing the position of XMAP215-coated polystyrene microspheres bound to the tips of dynamic microtubules. The microspheres, so-called "beads," served as handles to apply forces on XMAP215 molecules using optical tweezers. Results XMAP215-Coated Beads Remain Attached to Growing ...

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“…Furthermore, these authors reported that Stu2 also promotes catastrophe, the transition of growing microtubules to shrinking ones, which often correlates with slower growth rates. One interpretation of these results is that not all members of the XMAP215/Dis1 family are polymerases and that the shared protein domains, notably the TOG domains (13,14), may have divergent activities.…”

mentioning

confidence: 98%

Stu2, the Budding Yeast XMAP215/Dis1 Homolog, Promotes Assembly of Yeast Microtubules by Increasing Growth Rate and Decreasing Catastrophe Frequency

Podolski

Mahamdeh

Howard

2014

Journal of Biological Chemistry

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Background:The reported inhibition of microtubule growth by Stu2 is difficult to reconcile with its cellular phenotypes. Results: Using microscopy assays, we found that Stu2 increases the growth rate and decreases the catastrophe frequency of yeast microtubules. Conclusion: Stu2 promotes microtubule growth, with considerably higher activity on budding yeast microtubules. Significance: The biochemical properties of Stu2 reported here account for the mitotic phenotypes observed in cells.

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A TOG:αβ-tubulin Complex Structure Reveals Conformation-Based Mechanisms for a Microtubule Polymerase

Cited by 227 publications

References 33 publications

Biochemical and Structural Insights into Microtubule Perturbation by CopN from Chlamydia pneumoniae

Biochemical and Structural Insights into Microtubule Perturbation by CopN from Chlamydia pneumoniae

The growth speed of microtubules with XMAP215-coated beads coupled to their ends is increased by tensile force

Stu2, the Budding Yeast XMAP215/Dis1 Homolog, Promotes Assembly of Yeast Microtubules by Increasing Growth Rate and Decreasing Catastrophe Frequency

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