Microtubule nucleation: The waltz between γ-tubulin ring complex and associated proteins

Liu, Peng; Würtz, Martin; Župa, Erik; Pfeffer, Stefan; Schiebel, Elmar

doi:10.1016/j.ceb.2020.10.004

Cited by 59 publications

(48 citation statements)

References 45 publications

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“…In the rod-shaped bacterium Escherichia coli, left-handed chirality of the MreB cytoskeleton What determines the predominance of 13-protofilament microtubules in vivo, in contrast to the variabilities observed in vitro? The γ-tubulin-containing ring complex templates nucleation of a 13-protofilament microtubule, by arranging 13 γ-tubulins in a washer-like shape that matches the minus-end geometry of a nascent microtubule (Figure 3) [58]. An Arabidopsis mutant which has a defect in a component of the ring complex shows strong right-handed helical growth phenotypes in elongating tissues [29].…”

Section: Discussionmentioning

confidence: 99%

Mechanistic Insights into Plant Chiral Growth

Nakamura

Hashimoto

2020

Symmetry

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The latent left–right asymmetry (chirality) of vascular plants is best witnessed as a helical elongation of cylindrical organs in climbing plants. Interestingly, helical handedness is usually fixed in given species, suggesting genetic control of chirality. Arabidopsis thaliana, a small mustard plant, normally does not twist but can be mutated to exhibit helical growth in elongating organs. Genetic, molecular and cell biological analyses of these twisting mutants are providing mechanistic insights into the left–right handedness as well as how potential organ skewing is suppressed in most plants. Growth direction of elongating plant cells is determined by alignment of cellulose microfibrils in cell walls, which is guided by cortical microtubules localized just beneath the plasma membrane. Mutations in tubulins and regulators of microtubule assembly or organization give rise to helical arrangements of cortical microtubule arrays in Arabidopsis cells and cause helical growth of fixed handedness in axial organs such as roots and stems. Whether tubulins are assembled into a microtubule composed of straight or tilted protofilaments might determine straight or twisting growth. Mechanistic understanding of helical plant growth will provide a paradigm for connecting protein filament structure to cellular organization.

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Section: Discussionmentioning

confidence: 99%

Mechanistic Insights into Plant Chiral Growth

Nakamura

Hashimoto

2020

Symmetry

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“…γ-TuRC is a cone-shaped protein assembly, over 2 MDa in size ( Zheng et al, 1995 ; Oegema et al, 1999 ; Murphy et al, 2001 ; Liu et al, 2021 ). It contains a ring of γ-tubulins, which serves as an initiation point for the assembly of α-β tubulin subunits into a cylindrical microtubule ( Kollman et al, 2008 ; Consolati et al, 2020 ; Liu et al, 2020 ; Wieczorek et al, 2020 ).…”

Section: How Geometrical Features Of Microtubules Direct Array Organizationmentioning

confidence: 99%

Micron-scale geometrical features of microtubules as regulators of microtubule organization

Mani

Wijeratne

Subramanian

2021

eLife

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The organization of micron-sized, multi-microtubule arrays from individual microtubules is essential for diverse cellular functions. The microtubule polymer is largely viewed as a passive building block during the organization process. An exception is the ‘tubulin code’ where alterations to tubulin at the amino acid level can influence the activity of microtubule-associated proteins. Recent studies reveal that micron-scale geometrical features of individual microtubules and polymer networks, such as microtubule length, overlap length, contact angle, and lattice defects, can also regulate the activity of microtubule-associated proteins and modulate polymer dynamics. We discuss how the interplay between such geometrical properties of the microtubule lattice and the activity of associated proteins direct multiple aspects of array organization, from microtubule nucleation and coalignment to specification of array dimensions and remodeling of dynamic networks. The mechanisms reviewed here highlight micron-sized features of microtubules as critical parameters to be routinely investigated in the study of microtubule self-organization.

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“…Significant changes of amino acids (%) in Homo sapiens γ-tubulin1/2, Schizosaccharomyces pombe and Aspergillus nidulans γ-tubulin compared with γ-tubulin1 of Arabidopsis thaliana. γ-Tubulin is predominantly localized at centrosomes and spindle pole bodies and its specialized role in microtubule nucleation is generally accepted [6,7]. In acentrosomal plant cells, γ-tubulin is present in the cytosol, predominantly associating with microtubular arrays [8].…”

Section: Figure 1 (A)mentioning

confidence: 99%

“…The widespread role of γ-tubulin in microtubule nucleation and the mechanisms of microtubule nucleation by γ-tubulin complexes was recently reviewed [6]. There is, however, a growing amount of evidence for MTOC proteins with functions in nucleation, anchoring or regulation.…”

Section: Complexes Of γ-Tubulin With γ-Tubulin Complex Proteins Gcps Are the Best-established Microtubule Nucleatorsmentioning

confidence: 99%

γ-Tubulin Complexes and Fibrillar Arrays: Two Conserved High Molecular Forms with Many Cellular Functions

Chumová

Kourová

Trögelová

et al. 2021

Cells

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Higher plants represent a large group of eukaryotes where centrosomes are absent. The functions of γ-tubulin small complexes (γ-TuSCs) and γ-tubulin ring complexes (γ-TuRCs) in metazoans and fungi in microtubule nucleation are well established and the majority of components found in the complexes are present in plants. However, plant microtubules are also nucleated in a γ-tubulin-dependent but γ-TuRC-independent manner. There is growing evidence that γ-tubulin is a microtubule nucleator without being complexed in γ-TuRC. Fibrillar arrays of γ-tubulin were demonstrated in plant and animal cells and the ability of γ-tubulin to assemble into linear oligomers/polymers was confirmed in vitro for both native and recombinant γ-tubulin. The functions of γ-tubulin as a template for microtubule nucleation or in promoting spontaneous nucleation is outlined. Higher plants represent an excellent model for studies on the role of γ-tubulin in nucleation due to their acentrosomal nature and high abundancy and conservation of γ-tubulin including its intrinsic ability to assemble filaments. The defining scaffolding or sequestration functions of plant γ-tubulin in microtubule organization or in nuclear processes will help our understanding of its cellular roles in eukaryotes.

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Microtubule nucleation: The waltz between γ-tubulin ring complex and associated proteins

Cited by 59 publications

References 45 publications

Mechanistic Insights into Plant Chiral Growth

Mechanistic Insights into Plant Chiral Growth

Micron-scale geometrical features of microtubules as regulators of microtubule organization

γ-Tubulin Complexes and Fibrillar Arrays: Two Conserved High Molecular Forms with Many Cellular Functions

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