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Rale MJ, Romer B, Mahon BP, Travis SM, Petry S. The conserved centrosomin motif, γTuNA, forms a dimer that directly activates microtubule nucleation by the γ-tubulin ring complex (γTuRC). eLife 2022; 11:e80053. [PMID: 36515268 PMCID: PMC9859039 DOI: 10.7554/elife.80053] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 12/07/2022] [Indexed: 12/15/2022] Open
Abstract
To establish the microtubule cytoskeleton, the cell must tightly regulate when and where microtubules are nucleated. This regulation involves controlling the initial nucleation template, the γ-tubulin ring complex (γTuRC). Although γTuRC is present throughout the cytoplasm, its activity is restricted to specific sites including the centrosome and Golgi. The well-conserved γ-tubulin nucleation activator (γTuNA) domain has been reported to increase the number of microtubules (MTs) generated by γTuRCs. However, previously we and others observed that γTuNA had a minimal effect on the activity of antibody-purified Xenopus γTuRCs in vitro (Thawani et al., eLife, 2020; Liu et al., 2020). Here, we instead report, based on improved versions of γTuRC, γTuNA, and our TIRF assay, the first real-time observation that γTuNA directly increases γTuRC activity in vitro, which is thus a bona fide γTuRC activator. We further validate this effect in Xenopus egg extract. Via mutation analysis, we find that γTuNA is an obligate dimer. Moreover, efficient dimerization as well as γTuNA's L70, F75, and L77 residues are required for binding to and activation of γTuRC. Finally, we find that γTuNA's activating effect opposes inhibitory regulation by stathmin. In sum, our improved assays prove that direct γTuNA binding strongly activates γTuRCs, explaining previously observed effects of γTuNA expression in cells and illuminating how γTuRC-mediated microtubule nucleation is regulated.
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Affiliation(s)
- Michael J Rale
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Brianna Romer
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Brian P Mahon
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Sophie M Travis
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Sabine Petry
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
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Barh D, Tiwari S, Gabriel Rodrigues Gomes L, Weener ME, Alzahrani KJ, Alsharif KF, Aljabali AAA, Tambuwala MM, Lundstrom K, Hassan SS, Serrano-Aroca Á, Takayama K, Ghosh P, Redwan EM, Silva Andrade B, Soares SDC, Azevedo V, Uversky VN. Potential Molecular Mechanisms of Rare Anti-Tumor Immune Response by SARS-CoV-2 in Isolated Cases of Lymphomas. Viruses 2021; 13:v13101927. [PMID: 34696358 PMCID: PMC8539762 DOI: 10.3390/v13101927] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/07/2021] [Accepted: 09/22/2021] [Indexed: 12/12/2022] Open
Abstract
Recently, two cases of complete remission of classical Hodgkin lymphoma (cHL) and follicular lymphoma (FL) after SARS-CoV-2 infection were reported. However, the precise molecular mechanism of this rare event is yet to be understood. Here, we hypothesize a potential anti-tumor immune response of SARS-CoV-2 and based on a computational approach show that: (i) SARS-CoV-2 Spike-RBD may bind to the extracellular domains of CD15, CD27, CD45, and CD152 receptors of cHL or FL and may directly inhibit cell proliferation. (ii) Alternately, upon internalization after binding to these CD molecules, the SARS-CoV-2 membrane (M) protein and ORF3a may bind to gamma-tubulin complex component 3 (GCP3) at its tubulin gamma-1 chain (TUBG1) binding site. (iii) The M protein may also interact with TUBG1, blocking its binding to GCP3. (iv) Both the M and ORF3a proteins may render the GCP2-GCP3 lateral binding where the M protein possibly interacts with GCP2 at its GCP3 binding site and the ORF3a protein to GCP3 at its GCP2 interacting residues. (v) Interactions of the M and ORF3a proteins with these gamma-tubulin ring complex components potentially block the initial process of microtubule nucleation, leading to cell-cycle arrest and apoptosis. (vi) The Spike-RBD may also interact with and block PD-1 signaling similar to pembrolizumab and nivolumab- like monoclonal antibodies and may induce B-cell apoptosis and remission. (vii) Finally, the TRADD interacting “PVQLSY” motif of Epstein-Barr virus LMP-1, that is responsible for NF-kB mediated oncogenesis, potentially interacts with SARS-CoV-2 Mpro, NSP7, NSP10, and spike (S) proteins, and may inhibit the LMP-1 mediated cell proliferation. Taken together, our results suggest a possible therapeutic potential of SARS-CoV-2 in lymphoproliferative disorders.
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Affiliation(s)
- Debmalya Barh
- Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology (IIOAB), Nonakuri, Purba Medinipur 721172, West Bengal, India
- Department of Genetics, Ecology and Evolution, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil; (S.T.); (L.G.R.G.); (V.A.)
- Correspondence:
| | - Sandeep Tiwari
- Department of Genetics, Ecology and Evolution, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil; (S.T.); (L.G.R.G.); (V.A.)
| | - Lucas Gabriel Rodrigues Gomes
- Department of Genetics, Ecology and Evolution, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil; (S.T.); (L.G.R.G.); (V.A.)
| | - Marianna E. Weener
- Clinical Research Center, Oftalmic, CRO, 119334 Bardina Str. 22/4, 119991 Moscow, Russia;
| | - Khalid J. Alzahrani
- Department of Clinical Laboratories Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia; (K.J.A.); (K.F.A.)
| | - Khalaf F. Alsharif
- Department of Clinical Laboratories Sciences, College of Applied Medical Sciences, Taif University, Taif 21944, Saudi Arabia; (K.J.A.); (K.F.A.)
| | - Alaa A. A. Aljabali
- Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy, Yarmouk University, Irbid 21163, Jordan;
| | - Murtaza M. Tambuwala
- School of Pharmacy and Pharmaceutical Science, Ulster University, Coleraine BT52 1SA, UK;
| | | | - Sk. Sarif Hassan
- Department of Mathematics, Pingla Thana Mahavidyalaya, Maligram, Paschim Medinipur 721140, West Bengal, India;
| | - Ángel Serrano-Aroca
- Biomaterials and Bioengineering Lab, Centro de Investigación Traslacional San Alberto Magno, Universidad Católica de Valencia San Vicente Mártir, 46001 Valencia, Spain;
| | - Kazuo Takayama
- Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto 606-8507, Japan;
| | - Preetam Ghosh
- Department of Computer Science, Virginia Commonwealth University, Richmond, VA 23284, USA;
| | - Elrashdy M. Redwan
- Department of Biological Science, Faculty of Science, King Abdulazizi University, Jeddah 21589, Saudi Arabia;
| | - Bruno Silva Andrade
- Laboratory of Bioinformatics and Computational Chemistry, Department of Biological Sciences, State University of Southwest Bahia (UESB), Jequié 45206-190, Brazil;
| | - Siomar de Castro Soares
- Department of Immunology, Microbiology and Parasitology, Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro (UFTM), Uberaba 38025-180, Brazil;
| | - Vasco Azevedo
- Department of Genetics, Ecology and Evolution, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil; (S.T.); (L.G.R.G.); (V.A.)
| | - Vladimir N. Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer’s Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA;
- Research Center for Molecular Mechanisms of Aging and Age-Related Diseases, Moscow Institute of Physics and Technology, Institutskiy pereulok, 9, 141700 Dolgoprudny, Russia
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Böhler A, Vermeulen BJA, Würtz M, Zupa E, Pfeffer S, Schiebel E. The gamma-tubulin ring complex: Deciphering the molecular organization and assembly mechanism of a major vertebrate microtubule nucleator. Bioessays 2021; 43:e2100114. [PMID: 34160844 DOI: 10.1002/bies.202100114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 11/10/2022]
Abstract
Microtubules are protein cylinders with functions in cell motility, signal sensing, cell organization, intracellular transport, and chromosome segregation. One of the key properties of microtubules is their dynamic architecture, allowing them to grow and shrink in length by adding or removing copies of their basic subunit, the heterodimer αβ-tubulin. In higher eukaryotes, de novo assembly of microtubules from αβ-tubulin is initiated by a 2 MDa multi-subunit complex, the gamma-tubulin ring complex (γ-TuRC). For many years, the structure of the γ-TuRC and the function of its subunits remained enigmatic, although structural data from the much simpler yeast counterpart, the γ-tubulin small complex (γ-TuSC), were available. Two recent breakthroughs in the field, high-resolution structural analysis and recombinant reconstitution of the complex, have revolutionized our knowledge about the architecture and function of the γ-TuRC and will form the basis for addressing outstanding questions about biogenesis and regulation of this essential microtubule organizer.
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Affiliation(s)
- Anna Böhler
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Bram J A Vermeulen
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Martin Würtz
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Erik Zupa
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
| | - Elmar Schiebel
- Zentrum für Molekulare Biologie der Universität Heidelberg, Heidelberg, Germany
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Thawani A, Rale MJ, Coudray N, Bhabha G, Stone HA, Shaevitz JW, Petry S. The transition state and regulation of γ-TuRC-mediated microtubule nucleation revealed by single molecule microscopy. eLife 2020; 9:e54253. [PMID: 32538784 PMCID: PMC7338055 DOI: 10.7554/elife.54253] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 06/15/2020] [Indexed: 12/31/2022] Open
Abstract
Determining how microtubules (MTs) are nucleated is essential for understanding how the cytoskeleton assembles. While the MT nucleator, γ-tubulin ring complex (γ-TuRC) has been identified, precisely how γ-TuRC nucleates a MT remains poorly understood. Here, we developed a single molecule assay to directly visualize nucleation of a MT from purified Xenopus laevis γ-TuRC. We reveal a high γ-/αβ-tubulin affinity, which facilitates assembly of a MT from γ-TuRC. Whereas spontaneous nucleation requires assembly of 8 αβ-tubulins, nucleation from γ-TuRC occurs efficiently with a cooperativity of 4 αβ-tubulin dimers. This is distinct from pre-assembled MT seeds, where a single dimer is sufficient to initiate growth. A computational model predicts our kinetic measurements and reveals the rate-limiting transition where laterally associated αβ-tubulins drive γ-TuRC into a closed conformation. NME7, TPX2, and the putative activation domain of CDK5RAP2 h γ-TuRC-mediated nucleation, while XMAP215 drastically increases the nucleation efficiency by strengthening the longitudinal γ-/αβ-tubulin interaction.
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Affiliation(s)
- Akanksha Thawani
- Department of Chemical and Biological Engineering, Princeton UniversityPrincetonUnited States
| | - Michael J Rale
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Nicolas Coudray
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Gira Bhabha
- Department of Cell Biology, New York University School of MedicineNew YorkUnited States
| | - Howard A Stone
- Department of Mechanical and Aerospace Engineering, Princeton UniversityPrincetonUnited States
| | - Joshua W Shaevitz
- Lewis-Sigler Institute for Integrative GenomicsPrincetonUnited States
- Department of Physics, Princeton UniversityPrincetonUnited States
| | - Sabine Petry
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
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Tovey CA, Conduit PT. Microtubule nucleation by γ-tubulin complexes and beyond. Essays Biochem 2018; 62:765-80. [PMID: 30315097 DOI: 10.1042/EBC20180028] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 09/05/2018] [Accepted: 09/13/2018] [Indexed: 12/21/2022]
Abstract
In this short review, we give an overview of microtubule nucleation within cells. It is nearly 30 years since the discovery of γ-tubulin, a member of the tubulin superfamily essential for proper microtubule nucleation in all eukaryotes. γ-tubulin associates with other proteins to form multiprotein γ-tubulin ring complexes (γ-TuRCs) that template and catalyse the otherwise kinetically unfavourable assembly of microtubule filaments. These filaments can be dynamic or stable and they perform diverse functions, such as chromosome separation during mitosis and intracellular transport in neurons. The field has come a long way in understanding γ-TuRC biology but several important and unanswered questions remain, and we are still far from understanding the regulation of microtubule nucleation in a multicellular context. Here, we review the current literature on γ-TuRC assembly, recruitment, and activation and discuss the potential importance of γ-TuRC heterogeneity, the role of non-γ-TuRC proteins in microtubule nucleation, and whether γ-TuRCs could serve as good drug targets for cancer therapy.
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Tovey CA, Tubman CE, Hamrud E, Zhu Z, Dyas AE, Butterfield AN, Fyfe A, Johnson E, Conduit PT. γ-TuRC Heterogeneity Revealed by Analysis of Mozart1. Curr Biol 2018; 28:2314-2323.e6. [PMID: 29983314 PMCID: PMC6065531 DOI: 10.1016/j.cub.2018.05.044] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 04/06/2018] [Accepted: 05/16/2018] [Indexed: 12/13/2022]
Abstract
Microtubules are essential for various cell processes [1] and are nucleated by multi-protein γ-tubulin ring complexes (γ-TuRCs) at various microtubule organizing centers (MTOCs), including centrosomes [2-6]. Recruitment of γ-TuRCs to different MTOCs at different times influences microtubule array formation, but how this is regulated remains an open question. It also remains unclear whether all γ-TuRCs within the same organism have the same composition and how any potential heterogeneity might influence γ-TuRC recruitment. MOZART1 (Mzt1) was recently identified as a γ-TuRC component [7, 8] and is conserved in nearly all eukaryotes [6, 9]. Mzt1 has so far been studied in cultured human cells, yeast, and plants; its absence leads to failures in γ-TuRC recruitment and cell division, resulting in cell death [7, 9-15]. Mzt1 is small (∼8.5 kDa), binds directly to core γ-TuRC components [9, 10, 14, 15], and appears to mediate the interaction between γ-TuRCs and proteins that tether γ-TuRCs to MTOCs [9, 15]. Here, we use Drosophila to investigate the function of Mzt1 in a multicellular animal for the first time. Surprisingly, we find that Drosophila Mzt1 is expressed only in the testes and is present in γ-TuRCs recruited to basal bodies, but not to mitochondria, in developing sperm cells. mzt1 mutants are viable but have defects in basal body positioning and γ-TuRC recruitment to centriole adjuncts; sperm formation is affected and mutants display a rapid age-dependent decline in sperm motility and male fertility. Our results reveal that tissue-specific and MTOC-specific γ-TuRC heterogeneity exist in Drosophila and highlight the complexity of γ-TuRC recruitment in a multicellular animal.
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Affiliation(s)
- Corinne A Tovey
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Chloe E Tubman
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Eva Hamrud
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Zihan Zhu
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Anna E Dyas
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Andrew N Butterfield
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Alex Fyfe
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Errin Johnson
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Paul T Conduit
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK.
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