1
|
Taheri A, Wang Z, Singal B, Guo F, Al-Bassam J. Cryo-EM structures of the tubulin cofactors reveal the molecular basis for the biogenesis of alpha/beta-tubulin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.29.577855. [PMID: 38405852 PMCID: PMC10889022 DOI: 10.1101/2024.01.29.577855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Microtubule polarity and dynamic polymerization originate from the self-association properties of the a-tubulin heterodimer. For decades, it has remained poorly understood how the tubulin cofactors, TBCD, TBCE, TBCC, and the Arl2 GTPase mediate a-tubulin biogenesis from α- and β-tubulins. Here, we use cryogenic electron microscopy to determine structures of tubulin cofactors bound to αβ-tubulin. These structures show that TBCD, TBCE, and Arl2 form a heterotrimeric cage-like TBC-DEG assembly around the a-tubulin heterodimer. TBCD wraps around Arl2 and almost entirely encircles -tubulin, while TBCE forms a lever arm that anchors along the other end of TBCD and rotates α-tubulin. Structures of the TBC-DEG-αβ-tubulin assemblies bound to TBCC reveal the clockwise rotation of the TBCE lever that twists a-tubulin by pulling its C-terminal tail while TBCD holds -tubulin in place. Altogether, these structures uncover transition states in αβ-tubulin biogenesis, suggesting a vise-like mechanism for the GTP-hydrolysis dependent a-tubulin biogenesis mediated by TBC-DEG and TBCC. These structures provide the first evidence of the critical functions of the tubulin cofactors as enzymes that regulate the invariant organization of αβ-tubulin, by catalyzing α- and β-tubulin assembly, disassembly, and subunit exchange which are crucial for regulating the polymerization capacities of αβ-tubulins into microtubules.
Collapse
|
2
|
Zhou Q, Fu Z, Li M, Shen Q, Sun C, Feng Y, Liu Y, Jiang J, Qin T, Mao T, Hearne SJ, Wang G, Tang J. Maize tubulin folding cofactor B is required for cell division and cell growth through modulating microtubule homeostasis. THE NEW PHYTOLOGIST 2023. [PMID: 36843261 DOI: 10.1111/nph.18839] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 02/20/2023] [Indexed: 06/18/2023]
Abstract
Tubulin folding cofactors (TFCs) are required for tubulin folding, α/β tubulin heterodimer formation, and microtubule (MT) dynamics in yeast and mammals. However, the functions of their plant counterparts remain to be characterized. We identified a natural maize crumpled kernel mutant, crk2, which exhibits reductions in endosperm cell number and size, as well as embryo/seedling lethality. Map-based cloning and functional complementation confirmed that ZmTFCB is causal for the mutation. ZmTFCB is targeted mainly to the cytosol. It facilitates α-tubulin folding and heterodimer formation through sequential interactions with the cytosolic chaperonin-containing TCP-1 ε subunit ZmCCT5 and ZmTFCE, thus affecting the organization of both the spindle and phragmoplast MT array and the cortical MT polymerization and array formation, which consequently mediated cell division and cell growth. We detected a physical association between ZmTFCB and the maize MT plus-end binding protein END-BINDING1 (ZmEB1), indicating that ZmTFCB1 may modulate MT dynamics by sequestering ZmEB1. Our data demonstrate that ZmTFCB is required for cell division and cell growth through modulating MT homeostasis, an evolutionarily conserved machinery with some species-specific divergence.
Collapse
Affiliation(s)
- Qingqian Zhou
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Zhiyuan Fu
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Mengyuan Li
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Qingwen Shen
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Canran Sun
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Yijian Feng
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Yang Liu
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Jianjun Jiang
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Tao Qin
- College of Grassland Agriculture, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Tonglin Mao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Sarah Jane Hearne
- CIMMYT, KM 45 Carretera Mexico-Veracruz, El Batan, Texcoco, Estado de México, 56237, Mexico
| | - Guifeng Wang
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
| | - Jihua Tang
- National Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy, Henan Agricultural University, Zhengzhou, 450046, China
- The Shennong Laboratory, Zhengzhou, Henan, 450002, China
| |
Collapse
|
3
|
Zheng Y, Yang M, Chen X, Zhang G, Wan S, Zhang B, Huo J, Liu H. Decreased tubulin-binding cofactor B was involved in the formation disorder of nascent astrocyte processes by regulating microtubule plus-end growth through binding with end-binding proteins 1 and 3 after chronic alcohol exposure. Front Cell Neurosci 2022; 16:989945. [PMID: 36385945 PMCID: PMC9641617 DOI: 10.3389/fncel.2022.989945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 09/21/2022] [Indexed: 11/30/2022] Open
Abstract
Fetal alcohol syndrome (FAS) is a neurological disease caused by excessive drinking during pregnancy and characterized by congenital abnormalities in the structure and function of the fetal brain. This study was proposed to provide new insights into the pathogenesis of FAS by revealing the possible mechanisms of alcohol-induced astrocyte injury. First, a chronic alcohol exposure model of astrocytes was established, and the formation disorder was found in astrocyte processes where tubulin-binding cofactor B (TBCB) was decreased or lost, accompanied by disorganized microtubules (MT). Second, to understand the relationship between TBCB reduction and the formation disorder of astrocyte processes, TBCB was silenced or overexpressed. It caused astrocyte processes to retract or lose after silencing, while the processes increased with expending basal part and obtuse tips after overexpressing. It confirmed that TBCB was one of the critical factors for the formation of astrocyte processes through regulating MT plus-end and provided a new view on the pathogenesis of FAS. Third, to explore the mechanism of TBCB regulating MT plus-ends, we first proved end-binding proteins 1 and 3 (EB1/3) were bound at MT plus-ends in astrocytes. Then, through interference experiments, we found that both EB1 and EB3, which formed in heterodimers, were necessary to mediate TBCB binding to MT plus-ends and thus regulated the formation of astrocyte processes. Finally, the regulatory mechanism was studied and the ERK1/2 signaling pathway was found as one of the main pathways regulating the expression of TBCB in astrocytes after alcohol injury.
Collapse
Affiliation(s)
- Yin Zheng
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
- Department of Basic Medicine, Chongqing College of Traditional Chinese Medicine, Chongqing, China
| | - Mei Yang
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Xiaoqiao Chen
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Gaoli Zhang
- Institute for Viral Hepatitis, Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shanshan Wan
- Department of Blood Transfusion, Sichuan Cancer Hospital and Institute, Chengdu, China
| | - Bingqiu Zhang
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
| | - Jiechao Huo
- Fujian Province University Engineering Research Center of Mindong She Medicine, Medical College, Ningde Normal University, Ningde, China
| | - Hui Liu
- Institute of Neuroscience, Chongqing Medical University, Chongqing, China
- *Correspondence: Hui Liu
| |
Collapse
|
4
|
Montecinos F, Loew M, Chio TI, Bane SL, Sackett DL. Interaction of Colchicine-Site Ligands With the Blood Cell-Specific Isotype of β-Tubulin—Notable Affinity for Benzimidazoles. Front Cell Dev Biol 2022; 10:884287. [PMID: 35712668 PMCID: PMC9194530 DOI: 10.3389/fcell.2022.884287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
Tubulin, the main component of microtubules, is an α-β heterodimer that contains one of multiple isotypes of each monomer. Although the isotypes of each monomer are very similar, the beta tubulin isotype found in blood cells is significantly divergent in amino acid sequence compared to other beta tubulins. This isotype, beta class VI, coded by human gene TUBB1, is found in hematologic cells and is recognized as playing a role in platelet biogenesis and function. Tubulin from the erythrocytes of the chicken Gallus gallus contains almost exclusively βVI tubulin. This form of tubulin has been reported to differ from brain tubulin in binding of colchicine-site ligands, previously thought to be a ubiquitous characteristic of tubulin from higher eukaryotes. In this study, we sought to gain a better understanding of the structure-activity relationship of the colchicine site of this divergent isotype, using chicken erythrocyte tubulin (CeTb) as the model. We developed a fluorescence-based assay to detect binding of drugs to the colchicine site and used it to study the interaction of 53 colchicine-site ligands with CeTb. Among the ligands known to bind at this site, most colchicine derivatives had lower affinity for CeTb compared to brain tubulin. Remarkably, many of the benzimidazole class of ligands shows increased affinity for CeTb compared to brain tubulin. Because the colchicine site of human βVI tubulin is very similar to that of chicken βVI tubulin, these results may have relevance to the effect of anti-cancer agents on hematologic tissues in humans.
Collapse
Affiliation(s)
- Felipe Montecinos
- Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Maura Loew
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY, United States
| | - Tak I. Chio
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY, United States
| | - Susan L. Bane
- Department of Chemistry, Binghamton University, State University of New York, Binghamton, NY, United States
- *Correspondence: Susan L. Bane, ; Dan L. Sackett,
| | - Dan L. Sackett
- Division of Basic and Translational Biophysics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Susan L. Bane, ; Dan L. Sackett,
| |
Collapse
|
5
|
Métivier M, Gallaud E, Thomas A, Pascal A, Gagné JP, Poirier GG, Chrétien D, Gibeaux R, Richard-Parpaillon L, Benaud C, Giet R. Drosophila Tubulin-Specific Chaperone E Recruits Tubulin around Chromatin to Promote Mitotic Spindle Assembly. Curr Biol 2021; 31:684-695.e6. [PMID: 33259793 DOI: 10.1016/j.cub.2020.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 09/29/2020] [Accepted: 11/03/2020] [Indexed: 12/31/2022]
Abstract
Proper assembly of mitotic spindles requires microtubule nucleation not only at the centrosomes but also around chromatin. In this study, we found that the Drosophila tubulin-specific chaperone dTBCE is required for the enrichment of tubulin in the nuclear space after nuclear envelope breakdown and for subsequent promotion of spindle microtubule nucleation. These events depend on the CAP-Gly motif found in dTBCE and are regulated by Ran and lamin proteins. Our data suggest that during early mitosis, dTBCE and nuclear pore proteins become enriched in the nucleus, where they interact with the Ran GTPase to promote dynamic tubulin enrichment. We propose that this novel mechanism enhances microtubule nucleation around chromatin, thereby facilitating mitotic spindle assembly.
Collapse
Affiliation(s)
- Mathieu Métivier
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Emmanuel Gallaud
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Alexandre Thomas
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Aude Pascal
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Jean-Philippe Gagné
- Centre de Recherche du Centre Hospitalier Universitaire de Québec - Pavillon CHUL, Université Laval, Québec City, QC, Canada
| | - Guy G Poirier
- Centre de Recherche du Centre Hospitalier Universitaire de Québec - Pavillon CHUL, Université Laval, Québec City, QC, Canada
| | - Denis Chrétien
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Romain Gibeaux
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Laurent Richard-Parpaillon
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Christelle Benaud
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Régis Giet
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France.
| |
Collapse
|
6
|
Wang LL, Lee KT, Jung KW, Lee DG, Bahn YS. The novel microtubule-associated CAP-glycine protein Cgp1 governs growth, differentiation, and virulence of Cryptococcus neoformans. Virulence 2018; 9:566-584. [PMID: 29338542 PMCID: PMC5955475 DOI: 10.1080/21505594.2017.1423189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Microtubules are involved in mechanical support, cytoplasmic organization, and several cellular processes by interacting with diverse microtubule-associated proteins such as plus-end tracking proteins, motor proteins, and tubulin-folding cofactors. A number of the cytoskeleton-associated proteins (CAPs) contain the CAP-glycine-rich (CAP-Gly) domain, which is evolutionarily conserved and generally considered to bind to α-tubulin to regulate the function of microtubules. However, there has been a dearth of research on CAP-Gly proteins in fungal pathogens, including Cryptococcus neoformans, which is a global cause of fatal meningoencephalitis in immunocompromised patients. In this study, we identified five CAP-Gly protein-encoding genes in C. neoformans. Among these, Cgp1 encoded by CNAG_06352 has a unique domain structure containing CAP-Gly, SPEC, and Spc7 domains that is not orthologous to CAPs in other eukaryotes. Supporting the role of Cgp1 in microtubule-related function, we demonstrate that deletion or overexpression of CGP1 alters cellular susceptibility to thiabendazole, a microtubule destabilizer and that Cgp1 is co-localized with cytoplasmic microtubules. Related to the cellular function of microtubules, Cgp1 governs the maintenance of membrane stability and genotoxic stress responses. Deletion of CGP1 also reduces production of melanin pigment and attenuates the virulence of C. neoformans. Furthermore, we demonstrate that Cgp1 uniquely regulates the sexual differentiation of C. neoformans with distinct roles in the early and late stage of mating. Domain analysis revealed that the CAP-Gly domain plays a major role in all Cgp1 functions examined. In conclusion, this novel CAP-Gly protein, Cgp1, has pleotropic roles in regulating growth, stress responses, differentiation, and virulence in C. neoformans.
Collapse
Affiliation(s)
- Li Li Wang
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea
| | - Kyung-Tae Lee
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea
| | - Kwang-Woo Jung
- b Research Division for Biotechnology, Korea Atomic Energy Research Institute , Jeongeup , Republic of Korea
| | - Dong-Gi Lee
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea
| | - Yong-Sun Bahn
- a Department of Biotechnology , College of Life Science and Biotechnology, Yonsei University , Seoul , Republic of Korea
| |
Collapse
|
7
|
Al-Bassam J. Revisiting the tubulin cofactors and Arl2 in the regulation of soluble αβ-tubulin pools and their effect on microtubule dynamics. Mol Biol Cell 2017; 28:359-363. [PMID: 28137948 PMCID: PMC5341719 DOI: 10.1091/mbc.e15-10-0694] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 11/22/2016] [Accepted: 12/01/2016] [Indexed: 12/12/2022] Open
Abstract
Soluble αβ-tubulin heterodimers are maintained at high concentration inside eukaryotic cells, forming pools that fundamentally drive microtubule dynamics. Five conserved tubulin cofactors and ADP ribosylation factor-like 2 regulate the biogenesis and degradation of αβ-tubulins to maintain concentrated soluble pools. Here I describe a revised model for the function of three tubulin cofactors and Arl2 as a multisubunit GTP-hydrolyzing catalytic chaperone that cycles to promote αβ-tubulin biogenesis and degradation. This model helps explain old and new data indicating these activities enhance microtubule dynamics in vivo via repair or removal of αβ-tubulins from the soluble pools.
Collapse
Affiliation(s)
- Jawdat Al-Bassam
- Molecular Cellular Biology, University of California, Davis, Davis, CA 95616
| |
Collapse
|
8
|
Nithianantham S, Le S, Seto E, Jia W, Leary J, Corbett KD, Moore JK, Al-Bassam J. Tubulin cofactors and Arl2 are cage-like chaperones that regulate the soluble αβ-tubulin pool for microtubule dynamics. eLife 2015. [PMID: 26208336 PMCID: PMC4574351 DOI: 10.7554/elife.08811] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Microtubule dynamics and polarity stem from the polymerization of
αβ-tubulin heterodimers. Five conserved tubulin cofactors/chaperones
and the Arl2 GTPase regulate α- and β-tubulin assembly into
heterodimers and maintain the soluble tubulin pool in the cytoplasm, but their
physical mechanisms are unknown. Here, we reconstitute a core tubulin chaperone
consisting of tubulin cofactors TBCD, TBCE, and Arl2, and reveal a cage-like
structure for regulating αβ-tubulin. Biochemical assays and electron
microscopy structures of multiple intermediates show the sequential binding of
αβ-tubulin dimer followed by tubulin cofactor TBCC onto this chaperone,
forming a ternary complex in which Arl2 GTP hydrolysis is activated to alter
αβ-tubulin conformation. A GTP-state locked Arl2 mutant inhibits
ternary complex dissociation in vitro and causes severe defects in microtubule
dynamics in vivo. Our studies suggest a revised paradigm for tubulin cofactors and
Arl2 functions as a catalytic chaperone that regulates soluble
αβ-tubulin assembly and maintenance to support microtubule
dynamics. DOI:http://dx.doi.org/10.7554/eLife.08811.001 Cells contain a network of protein filaments called microtubules. These filaments are
involved in many biological processes; for example, they help cells keep the right
shape, and they help to transport proteins and other materials inside cells. Two proteins called α-tubulin and β-tubulin are the building blocks of
microtubules. The filaments are very dynamic structures that can rapidly change
length as individual tubulin units are either added or removed to the filament ends.
Several proteins known as tubulin cofactors and an enzyme called Arl2 help to build a
vast pool of tubulin units that are able attach to the microtubules. These
units—called αβ-tubulin—are formed by α-tubulin
and β-tubulin binding to each other, but it not clear exactly what roles the
tubulin cofactors and Arl2 play in this process. Nithianantham et al. used a combination of microscopy and biochemical techniques to
study how the tubulin cofactors and Arl2 are organised, and their role in the
assembly of microtubules in yeast. The experiments show that Arl2 and two tubulin
cofactors associate with each other to form a stable ‘complex’ that has
a cage-like structure. A molecule of αβ-tubulin binds to the complex,
followed by another cofactor called TBCC. This activates the enzyme activity of Arl2,
which releases the energy needed to alter the shape of the αβ-tubulin.
Nithianantham et al. also found that yeast cells with a mutant form of Arl2 that
lacked enzyme activity had problems forming microtubules. Together, these findings show that the tubulin cofactors and Arl2 form a complex that
regulates the assembly and maintenance of αβ-tubulin. The next
challenge is to understand how this regulation influences the way that microtubules
grow and shrink inside cells. DOI:http://dx.doi.org/10.7554/eLife.08811.002
Collapse
Affiliation(s)
- Stanley Nithianantham
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Sinh Le
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Elbert Seto
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Weitao Jia
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Julie Leary
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| | - Kevin D Corbett
- Ludwig Institute for Cancer Research, University of California, San Diego, San Diego, United States
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, United States
| | - Jawdat Al-Bassam
- Department of Molecular Cellular Biology, University of California, Davis, Davis, United States
| |
Collapse
|
9
|
Kang X, Jiang L, Chen X, Yuan H, Luo C, Ouyang Q. Pump-free multi-well-based microfluidic system for high-throughput analysis of size-control relative genes in budding yeast. Integr Biol (Camb) 2014; 6:685-93. [PMID: 24872017 DOI: 10.1039/c4ib00054d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-lapse single cell imaging by microscopy can provide precise cell information such as the cell size, the cell cycle duration, protein localization and protein expression level. Usually, a microfluidic system is needed for these measurements in order to provide a constant culture environment and confine the cells so that they grow in a monolayer. However, complex connections are required between the channels inside the chip and the outside media, and a complex procedure is needed for loading of cells, thereby making this type of system unsuitable for application in high-throughput single cell scanning experiments. Here we provide a novel and easily operated pump-free multi-well-based microfluidic system which enables the high-throughput loading of many different budding yeast strains into monolayer growth conditions just by use of a multi-channel pipette. Wild type budding yeast (Saccharomyces cerevisiae) and 62 different budding yeast size control relative gene deletion strains were chosen for scanning. We obtained normalized statistical results for the mother cell doubling time, daughter cell doubling time, mother cell size and daughter cell size of different gene deletion strains relative to the corresponding parameters of the wild type cells. Meanwhile, we compared the typical cell morphology of different strains and analyzed the relationship between the cell genotype and phenotype. This method which can be easily used in a normal biology lab may help researchers who need to carry out the high-throughput scanning of cell morphology and growth.
Collapse
Affiliation(s)
- Xianjie Kang
- The State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, China.
| | | | | | | | | | | |
Collapse
|
10
|
Mori R, Toda T. The dual role of fission yeast Tbc1/cofactor C orchestrates microtubule homeostasis in tubulin folding and acts as a GAP for GTPase Alp41/Arl2. Mol Biol Cell 2013; 24:1713-24, S1-8. [PMID: 23576550 PMCID: PMC3667724 DOI: 10.1091/mbc.e12-11-0792] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/22/2013] [Accepted: 03/29/2013] [Indexed: 11/11/2022] Open
Abstract
Supplying the appropriate amount of correctly folded α/β-tubulin heterodimers is critical for microtubule dynamics. Formation of assembly-competent heterodimers is remarkably elaborate at the molecular level, in which the α- and β-tubulins are separately processed in a chaperone-dependent manner. This sequential step is performed by the tubulin-folding cofactor pathway, comprising a specific set of regulatory proteins: cofactors A-E. We identified the fission yeast cofactor: the orthologue of cofactor C, Tbc1. In addition to its roles in tubulin folding, Tbc1 acts as a GAP in regulating Alp41/Arl2, a highly conserved small GTPase. Of interest, the expression of GDP- or GTP-bound Alp41 showed the identical microtubule loss phenotype, suggesting that continuous cycling between these forms is important for its functions. In addition, we found that Alp41 interacts with Alp1(D), the orthologue of cofactor D, specifically when in the GDP-bound form. Intriguingly, Alp1(D) colocalizes with microtubules when in excess, eventually leading to depolymerization, which is sequestered by co-overproducing GDP-bound Alp41. We present a model of the final stages of the tubulin cofactor pathway that includes a dual role for both Tbc1 and Alp1(D) in opposing regulation of the microtubule.
Collapse
Affiliation(s)
- Risa Mori
- Cell Regulation Laboratory, Cancer Research UK, London Research Institute, Lincoln's Inn Fields Laboratories, London WC2A 3LY, United Kingdom
| | - Takashi Toda
- Cell Regulation Laboratory, Cancer Research UK, London Research Institute, Lincoln's Inn Fields Laboratories, London WC2A 3LY, United Kingdom
| |
Collapse
|
11
|
Three-dimensional structure of CAP-gly domain of mammalian dynactin determined by magic angle spinning NMR spectroscopy: conformational plasticity and interactions with end-binding protein EB1. J Mol Biol 2013; 425:4249-66. [PMID: 23648839 DOI: 10.1016/j.jmb.2013.04.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/25/2013] [Accepted: 04/26/2013] [Indexed: 11/23/2022]
Abstract
Microtubules and their associated proteins play important roles in vesicle and organelle transport, cell motility and cell division. Perturbation of these processes by mutation typically gives rise to severe pathological conditions. In our efforts to obtain atomic information on microtubule-associated protein/microtubule interactions with the goal to understand mechanisms that might potentially assist in the development of treatments for these diseases, we have determined the three-dimensional structure of CAP-Gly (cytoskeleton-associated protein, glycine-rich) domain of mammalian dynactin by magic angle spinning NMR spectroscopy. We observe two conformations in the β2 strand encompassing residues T43-V44-A45, residues that are adjacent to the disease-associated mutation, G59S. Upon binding of CAP-Gly to microtubule plus-end tracking protein EB1, the CAP-Gly shifts to a single conformer. We find extensive chemical shift perturbations in several stretches of residues of CAP-Gly upon binding to EB1, from which we define accurately the CAP-Gly/EB1 binding interface. We also observe that the loop regions may exhibit unique flexibility, especially in the GKNDG motif, which participates in the microtubule binding. This study in conjunction with our previous reports suggests that conformational plasticity is an intrinsic property of CAP-Gly likely due to its unusually high loop content and may be required for its biological functions.
Collapse
|
12
|
Carranza G, Castaño R, Fanarraga ML, Villegas JC, Gonçalves J, Soares H, Avila J, Marenchino M, Campos-Olivas R, Montoya G, Zabala JC. Autoinhibition of TBCB regulates EB1-mediated microtubule dynamics. Cell Mol Life Sci 2013; 70:357-71. [PMID: 22940919 PMCID: PMC11113326 DOI: 10.1007/s00018-012-1114-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 07/26/2012] [Accepted: 07/31/2012] [Indexed: 12/22/2022]
Abstract
Tubulin cofactors (TBCs) participate in the folding, dimerization, and dissociation pathways of the tubulin dimer. Among them, TBCB and TBCE are two CAP-Gly domain-containing proteins that together efficiently interact with and dissociate the tubulin dimer. In the study reported here we showed that TBCB localizes at spindle and midzone microtubules during mitosis. Furthermore, the motif DEI/M-COO(-) present in TBCB, which is similar to the EEY/F-COO(-) element characteristic of EB proteins, CLIP-170, and α-tubulin, is required for TBCE-TBCB heterodimer formation and thus for tubulin dimer dissociation. This motif is responsible for TBCB autoinhibition, and our analysis suggests that TBCB is a monomer in solution. Mutants of TBCB lacking this motif are derepressed and induce microtubule depolymerization through an interaction with EB1 associated with microtubule tips. TBCB is also able to bind to the chaperonin complex CCT containing α-tubulin, suggesting that it could escort tubulin to facilitate its folding and dimerization, recycling or degradation.
Collapse
Affiliation(s)
- Gerardo Carranza
- Departamento de Biología Molecular, Facultad de Medicina, IFIMAV-Universidad de Cantabria, 39011 Santander, Spain
| | - Raquel Castaño
- Departamento de Biología Molecular, Facultad de Medicina, IFIMAV-Universidad de Cantabria, 39011 Santander, Spain
| | - Mónica L. Fanarraga
- Departamento de Biología Molecular, Facultad de Medicina, IFIMAV-Universidad de Cantabria, 39011 Santander, Spain
| | - Juan Carlos Villegas
- Departamento de Anatomía y Biología Celular, Facultad de Medicina, IFIMAV-Universidad de Cantabria, 39011 Santander, Spain
| | - João Gonçalves
- Centro de Química eBioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisbon, Portugal
- Instituto Gulbenkian de Ciência, Ap. 14, 2781-901 Oeiras, Portugal
- Escola Superior de Tecnologia, Saude de Lisboa, 1990-096 Lisbon, Portugal
- Present Address: Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Room 1070, Toronto, ON M5G 1X5 Canada
| | - Helena Soares
- Centro de Química eBioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisbon, Portugal
- Instituto Gulbenkian de Ciência, Ap. 14, 2781-901 Oeiras, Portugal
- Escola Superior de Tecnologia, Saude de Lisboa, 1990-096 Lisbon, Portugal
| | - Jesus Avila
- Centro de Biología Molecular (CSIC-UAM), Universidad Autónoma de Madrid, 28049 Cantoblanco, Madrid, Spain
| | - Marco Marenchino
- Spectroscopy and NMR Unit, Structural Biology and Biocomputing Program, Spanish National Cancer Research Center (CNIO), Melchor Fdez. Almagro 3, 28029 Madrid, Spain
| | - Ramón Campos-Olivas
- Spectroscopy and NMR Unit, Structural Biology and Biocomputing Program, Spanish National Cancer Research Center (CNIO), Melchor Fdez. Almagro 3, 28029 Madrid, Spain
| | - Guillermo Montoya
- Macromolecular Crystallography Group, Structural Biology and Biocomputing Program, Spanish National Cancer Research Center (CNIO), Melchor Fdez. Almagro 3, 28029 Madrid, Spain
| | - Juan Carlos Zabala
- Departamento de Biología Molecular, Facultad de Medicina, IFIMAV-Universidad de Cantabria, 39011 Santander, Spain
| |
Collapse
|
13
|
Baffet AD, Benoit B, Januschke J, Audo J, Gourhand V, Roth S, Guichet A. Drosophila tubulin-binding cofactor B is required for microtubule network formation and for cell polarity. Mol Biol Cell 2012; 23:3591-601. [PMID: 22855530 PMCID: PMC3442407 DOI: 10.1091/mbc.e11-07-0633] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Microtubules (MTs) are essential for cell division, shape, intracellular transport, and polarity. MT stability is regulated by many factors, including MT-associated proteins and proteins controlling the amount of free tubulin heterodimers available for polymerization. Tubulin-binding cofactors are potential key regulators of free tubulin concentration, since they are required for α-β-tubulin dimerization in vitro. In this paper, we show that mutation of the Drosophila tubulin-binding cofactor B (dTBCB) affects the levels of both α- and β-tubulins and dramatically destabilizes the MT network in different fly tissues. However, we find that dTBCB is dispensable for the early MT-dependent steps of oogenesis, including cell division, and that dTBCB is not required for mitosis in several tissues. In striking contrast, the absence of dTBCB during later stages of oogenesis causes major defects in cell polarity. We show that dTBCB is required for the polarized localization of the axis-determining mRNAs within the oocyte and for the apico-basal polarity of the surrounding follicle cells. These results establish a developmental function for the dTBCB gene that is essential for viability and MT-dependent cell polarity, but not cell division.
Collapse
Affiliation(s)
- Alexandre D Baffet
- Institut Jacques Monod, CNRS, UMR 7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | | | | | | | | | | | | |
Collapse
|
14
|
Haldar S, Sarkar S, Singh V, Sinha P. High copies of SUM1 enhance the stability of wild-type microtubules against adverse conditions in Saccharomyces cerevisiae. Biochem Biophys Res Commun 2012; 418:525-30. [PMID: 22285862 DOI: 10.1016/j.bbrc.2012.01.059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/08/2012] [Indexed: 02/01/2023]
Abstract
The budding yeast transcriptional repressor Sum1p binds to several promoters and recruits Hst1p, an NAD(+)-dependent histone deacetylase, at these promoters with the help of another protein Rfm1p. Hst1p causes repression of transcription by histone deacetylation of chromatin at its target promoters. In an earlier work we have shown that about 13-fold increase in Sum1p levels, brought about by expressing SUM1 from the high copy 2 micron plasmid (2 μ-SUM1), suppressed cold-sensitive growth phenotype associated with mutations in the α-tubulin gene TUB1. In this work we show that the dosage suppression is accompanied by an elevation of α-tubulin levels in mutant cells at their non-permissive growth temperature of 14°C. Further, 2 μ-SUM1 significantly rescued the benomyl-supersensitive growth phenotype of mutant cells having wild-type tubulin subunits but a deficiency in tubulin folding cofactors. Finally, wild-type 2 μ-SUM1 transformants, having no known mutation in microtubule-related genes, displayed spindle microtubules which were substantially more stable than of wild-type control cells when challenged with microtubule-depolymerizing drugs. Therefore, we conclude that high copies of Sum1p stabilize microtubules against a variety of adverse and destabilizing conditions like mutations, low temperatures and drugs.
Collapse
Affiliation(s)
- Subhash Haldar
- Department of Biochemistry, Bose Institute, Kolkata 700054, India
| | | | | | | |
Collapse
|
15
|
Cohnen A, Bielig H, Hollenberg CP, Hu Z, Ramezani-Rad M. The yeast ubiquitin-like domain protein Mdy2 is required for microtubule-directed nuclear migration and localizes to cytoplasmic granules in response to heat stress. Cytoskeleton (Hoboken) 2011; 67:635-49. [PMID: 20722039 DOI: 10.1002/cm.20477] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
MDY2 encodes a ubiquitin-like (UBL)-domain protein necessary for efficient mating in Saccharomyces cerevisiae. Unlike most UBL proteins, Mdy2 is apparently not subject to C-terminal processing and is localized predominantly in the nucleus. Deletion of MDY2 is associated with a five- to seven-fold reduction in mating efficiency, mainly due to defects in nuclear migration and karyogamy at the prezygotic stage. Here, we looked for two potential interacting partners of Mdy2, investigated the function of Mdy2 in nuclear movement, determined the increased heat sensitivity defects of mdy2Δ mutants, and inspected localization of Mdy2. Coprecipitation studies show that Mdy2 associates with α-tubulin and with the microtubule (MT)-associated dynactin subunit p150(Glued)/Nip100. nip100Δ mutants exhibit no defects in nuclear migration or in MT length or orientation during shmooing growth. Deletion of MDY2 display small nuclear migration phenotype during vegetative growth and seems to exacerbate the defects in mitotic nuclear migration seen in the nip100Δ strain. Deletion of MDY2 increased heat sensitivity of the cells and these strains accumulate mitotic nuclear migration defects and shortened MTs under these conditions. GFP-Mdy2 proteins which are localized predominantly in the nucleus at permissive temperature are localized to cytoplasmic foci during heat shock. Colocalization studies revealed that heat stress-induced enrichment of Mdy2 in cytoplasmic foci merged mainly with stress granules marker Pab1. During glucose deprivation a minority of Mdy2 foci overlapped with P-bodies marker Dcp2, while most Mdy2 foci and Pab1 foci overlap. Accordingly, we propose that Mdy2 plays a critical role in the MT-dependent processes of karyogamy and stress response.
Collapse
Affiliation(s)
- André Cohnen
- Institute for Microbiology, Heinrich-Heine University, Düsseldorf, Germany
| | | | | | | | | |
Collapse
|
16
|
Sarkar S, Haldar S, Hajra S, Sinha P. The budding yeast protein Sum1 functions independently of its binding partners Hst1 and Sir2 histone deacetylases to regulate microtubule assembly. FEMS Yeast Res 2010; 10:660-73. [PMID: 20608984 DOI: 10.1111/j.1567-1364.2010.00655.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The budding yeast protein Sum1 is a transcription factor that associates with the histone deacetylase Hst1p or, in its absence, with Sir2p to form repressed chromatin. In this study, SUM1 has been identified as an allele-specific dosage suppressor of mutations in the major alpha-tubulin-coding gene TUB1. When cloned in a 2mu vector, SUM1 suppressed the cold-sensitive and benomyl-hypersensitive phenotypes associated with the tub1-1 mutation. The suppression was Hst1p- and Sir2p-independent, suggesting that it was not mediated by deacetylation events associated with Sum1p when it functions along with its known partner histone deacetylases. This protein was confined to the nucleus, but did not colocalize with the microtubules nor did it bind to alpha- or beta-tubulin. Cells deleted of SUM1 showed hypersensitivity to benomyl and cold-sensitive growth, phenotypes exhibited by mutants defective in microtubule function and cytoskeletal defects. These observations suggest that Sum1p is a novel regulator of microtubule function. We propose that as a dosage suppressor, Sum1p promotes the formation of microtubules by increasing the availability of the alphabeta-heterodimer containing the mutant alpha-tubulin subunit.
Collapse
Affiliation(s)
- Sourav Sarkar
- Department of Biochemistry, Bose Institute, Kolkata, India
| | | | | | | |
Collapse
|
17
|
Voloshin O, Gocheva Y, Gutnick M, Movshovich N, Bakhrat A, Baranes-Bachar K, Bar-Zvi D, Parvari R, Gheber L, Raveh D. Tubulin chaperone E binds microtubules and proteasomes and protects against misfolded protein stress. Cell Mol Life Sci 2010; 67:2025-38. [PMID: 20204449 PMCID: PMC11115895 DOI: 10.1007/s00018-010-0308-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 01/10/2010] [Accepted: 02/09/2010] [Indexed: 11/29/2022]
Abstract
Mutation of tubulin chaperone E (TBCE) underlies hypoparathyroidism, retardation, and dysmorphism (HRD) syndrome with defective microtubule (MT) cytoskeleton. TBCE/yeast Pac2 comprises CAP-Gly, LRR (leucine-rich region), and UbL (ubiquitin-like) domains. TBCE folds alpha-tubulin and promotes alpha/beta dimerization. We show that Pac2 functions in MT dynamics: the CAP-Gly domain binds alpha-tubulin and MTs, and functions in suppression of benomyl sensitivity of pac2Delta mutants. Pac2 binds proteasomes: the LRR binds Rpn1, and the UbL binds Rpn10; the latter interaction mediates Pac2 turnover. The UbL also binds the Skp1-Cdc53-F-box (SCF) ubiquitin ligase complex; these competing interactions for the UbL may impact on MT dynamics. pac2Delta mutants are sensitive to misfolded protein stress. This is suppressed by ectopic PAC2 with both the CAP-Gly and UbL domains being essential. We propose a novel role for Pac2 in the misfolded protein stress response based on its ability to interact with both the MT cytoskeleton and the proteasomes.
Collapse
Affiliation(s)
- Olga Voloshin
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Yana Gocheva
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Marina Gutnick
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Natalia Movshovich
- Department of Clinical Biochemistry, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Anya Bakhrat
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Keren Baranes-Bachar
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Dudy Bar-Zvi
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Ruti Parvari
- National Institute of Biotechnology Negev and Department of Virology and Developmental Genetics, Faculty of Health Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Larisa Gheber
- Department of Clinical Biochemistry, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| | - Dina Raveh
- Department of Life Sciences, Ben Gurion University of the Negev, P.O. Box 653, 84105 Beersheba, Israel
| |
Collapse
|
18
|
Wickström SA, Masoumi KC, Khochbin S, Fässler R, Massoumi R. CYLD negatively regulates cell-cycle progression by inactivating HDAC6 and increasing the levels of acetylated tubulin. EMBO J 2010; 29:131-44. [PMID: 19893491 PMCID: PMC2775896 DOI: 10.1038/emboj.2009.317] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Accepted: 10/07/2009] [Indexed: 02/02/2023] Open
Abstract
CYLD is a tumour-suppressor gene that is mutated in a benign skin tumour syndrome called cylindromatosis. The CYLD gene product is a deubiquitinating enzyme that was shown to regulate cell proliferation, cell survival and inflammatory responses, mainly through inhibiting NF-kappaB signalling. Here we show that CYLD controls cell growth and division at the G(1)/S-phase as well as cytokinesis by associating with alpha-tubulin and microtubules through its CAP-Gly domains. Translocation of activated CYLD to the perinuclear region of the cell is achieved by an inhibitory interaction of CYLD with histone deacetylase-6 (HDAC6) leading to an increase in the levels of acetylated alpha-tubulin around the nucleus. This facilitates the interaction of CYLD with Bcl-3, leading to a significant delay in the G(1)-to-S-phase transition. Finally, CYLD also interacts with HDAC6 in the midbody where it regulates the rate of cytokinesis in a deubiquitinase-independent manner. Altogether these results identify a mechanism by which CYLD regulates cell proliferation at distinct cell-cycle phases.
Collapse
Affiliation(s)
- Sara A Wickström
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Katarzyna C Masoumi
- Department of Laboratory Medicine, Lund University, Malmö University Hospital, Malmö, Sweden
| | - Saadi Khochbin
- INSERM, U823, Université Joseph Fourier, Institut Albert Bonniot, Grenoble, France
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Ramin Massoumi
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, Martinsried, Germany
- Department of Laboratory Medicine, Clinical Research Center, Lund University, Malmö University Hospital, Malmö, Sweden
| |
Collapse
|
19
|
Sun S, Siglin A, Williams JC, Polenova T. Solid-State and Solution NMR Studies of the CAP-Gly Domain of Mammalian Dynactin and Its Interaction with Microtubules. J Am Chem Soc 2009; 131:10113-26. [PMID: 19580321 DOI: 10.1021/ja902003u] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Shangjin Sun
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, and Department of Molecular Medicine, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, California 91010
| | - Amanda Siglin
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, and Department of Molecular Medicine, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, California 91010
| | - John C. Williams
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, and Department of Molecular Medicine, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, California 91010
| | - Tatyana Polenova
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, and Department of Molecular Medicine, Beckman Research Institute of City of Hope, 1500 East Duarte Road, Duarte, California 91010
| |
Collapse
|
20
|
Capturing protein tails by CAP-Gly domains. Trends Biochem Sci 2008; 33:535-45. [PMID: 18835717 DOI: 10.1016/j.tibs.2008.08.006] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 08/29/2008] [Accepted: 08/29/2008] [Indexed: 12/29/2022]
Abstract
Cytoskeleton-associated protein-glycine-rich (CAP-Gly) domains are protein-interaction modules implicated in important cellular processes and in hereditary human diseases. A prominent function of CAP-Gly domains is to bind to C-terminal EEY/F-COO(-) sequence motifs present in alpha-tubulin and in some microtubule-associated protein tails; however, CAP-Gly domains also interact with other structural elements including end-binding homology domains, zinc-finger motifs and proline-rich sequences. Recent findings unravelled the link between tubulin tyrosination and CAP-Gly-protein recruitment to microtubules. They further provided a molecular basis for understanding the role of CAP-Gly domains in controlling dynamic cellular processes including the tracking and regulation of microtubule ends. It is becoming increasingly clear that CAP-Gly domains are also involved in coordinating complex and diverse aspects of cell architecture and signalling.
Collapse
|
21
|
Gao J, Huo L, Sun X, Liu M, Li D, Dong JT, Zhou J. The tumor suppressor CYLD regulates microtubule dynamics and plays a role in cell migration. J Biol Chem 2008; 283:8802-9. [PMID: 18222923 DOI: 10.1074/jbc.m708470200] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The familial cylindromatosis tumor suppressor CYLD is known to contain three cytoskeleton-associated protein glycine-rich (CAP-Gly) domains, which exist in a number of microtubule-binding proteins and are responsible for their association with microtubules. However, it remains elusive whether CYLD interacts with microtubules and, if so, whether the interaction is mediated by the CAP-Gly domains. In this study, our data demonstrate that CYLD associates with microtubules both in cells and in vitro, and the first CAP-Gly domain of CYLD is mainly responsible for the interaction. Knockdown of cellular CYLD expression dramatically delays microtubule regrowth after nocodazole washout, indicating an activity for CYLD in promoting microtubule assembly. Our data further demonstrate that CYLD enhances tubulin polymerization into microtubules by lowering the critical concentration for microtubule assembly. In addition, we have identified by wound healing assay a critical role for CYLD in mediating cell migration and found that its first CAP-Gly domain is required for this activity. Thus CYLD joins a growing list of CAP-Gly domain-containing proteins that regulate microtubule dynamics and function.
Collapse
Affiliation(s)
- Jinmin Gao
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin, China
| | | | | | | | | | | | | |
Collapse
|
22
|
Hoppeler-Lebel A, Celati C, Bellett G, Mogensen MM, Klein-Hitpass L, Bornens M, Tassin AM. Centrosomal CAP350 protein stabilises microtubules associated with the Golgi complex. J Cell Sci 2007; 120:3299-308. [PMID: 17878239 DOI: 10.1242/jcs.013102] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A comprehensive model of how the centrosome organises the microtubule network in animal cells has not yet been elucidated. Here we show that the centrosomal large CAP-Gly protein CAP350 is not only present at the centrosome, but is also present as numerous dots in the pericentrosomal area. Using in vitro and in vivo expression of partial constructs, we demonstrated that CAP350 binds microtubules through an N-terminal basic region rather than through its CAP-Gly domain. CAP-Gly-containing domains of CAP350 are targeted not only to the centrosome but also to a Golgi-like network. Interestingly, full-length GFP-tagged CAP350 bound preferentially to microtubules in the pericentrosomal area. These results indicate that the large CAP350 protein has a dual binding ability. Overexpression of CAP350 promoted an increase in the stability of the whole microtubule network, as judged by a significant decrease in the number of EB1 comets and by an enhanced microtubule resistance to Nocodazole treatment. In support of this, CAP350 depletion decreased microtubule stability. Moreover, both depletion and overexpression of CAP350 induced specific fragmentation of the Golgi complex while maintaining a juxtanuclear localisation. We propose that CAP350 specifically stabilises Golgi-associated microtubules and in this way participates in the maintenance of a continuous pericentrosomal Golgi ribbon.
Collapse
|
23
|
Dhonukshe P, Bargmann BOR, Gadella TWJ. Arabidopsis
Tubulin Folding Cofactor B Interacts with α-Tubulin In Vivo. ACTA ACUST UNITED AC 2006; 47:1406-11. [PMID: 16928693 DOI: 10.1093/pcp/pcl001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Microtubule biogenesis requires alphabeta tubulin dimers that are generated from alpha and beta tubulin following post-translational modification by several tubulin folding cofactors (TFCs). Here we report the isolation and characterization of Arabidopsis TFCB (AtTFCB). AtTFCB is expressed in all organs of Arabidopsis. The subcellular localization of AtTFCB is mainly cytosolic. AtTFCB-overexpressing cells have fewer microtubules compared with the controls. Multimode fluorescence resonance energy transfer (FRET) microscopy reveals a direct physical interaction of AtTFCB with alpha tubulin in living plant cells. We conclude that AtTFCB interacts with alpha tubulin in vivo and its overexpression reduces the number of microtubules.
Collapse
Affiliation(s)
- Pankaj Dhonukshe
- Section of Molecular Cytology, Swammerdam Institute for Life Sciences, University of Amsterdam, Kruislaan 316, 1098 SM Amsterdam, The Netherlands.
| | | | | |
Collapse
|
24
|
Honnappa S, Okhrimenko O, Jaussi R, Jawhari H, Jelesarov I, Winkler FK, Steinmetz MO. Key interaction modes of dynamic +TIP networks. Mol Cell 2006; 23:663-71. [PMID: 16949363 DOI: 10.1016/j.molcel.2006.07.013] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 06/27/2006] [Accepted: 07/13/2006] [Indexed: 11/22/2022]
Abstract
Dynamic microtubule plus-end tracking protein (+TIP) networks are implicated in all functions of microtubules, but the molecular determinants of their interactions are largely unknown. Here, we have explored key binding modes of +TIPs by analyzing the interactions between selected CAP-Gly, EB-like, and carboxy-terminal EEY/F-COO(-) sequence motifs. X-ray crystallography and biophysical binding studies demonstrate that the beta2-beta3 loop of CAP-Gly domains determines EB-like motif binding specificity. They further show how CAP-Gly domains serve as recognition domains for EEY/F-COO(-) motifs, which represent characteristic and functionally important sequence elements in EB, CLIP-170, and alpha-tubulin. Our findings provide a molecular basis for understanding the modular interaction modes between alpha-tubulin, CLIPs, EB proteins, and the dynactin-dynein motor complex and suggest that multiple low-affinity binding sites in different combinations control dynamic +TIP networks at microtubule ends. They further offer insights into the structural consequences of genetic CAP-Gly domain defects found in severe human disorders.
Collapse
Affiliation(s)
- Srinivas Honnappa
- Biomolecular Research, Structural Biology, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland
| | | | | | | | | | | | | |
Collapse
|
25
|
Kortazar D, Fanarraga ML, Carranza G, Bellido J, Villegas JC, Avila J, Zabala JC. Role of cofactors B (TBCB) and E (TBCE) in tubulin heterodimer dissociation. Exp Cell Res 2006; 313:425-36. [PMID: 17184771 DOI: 10.1016/j.yexcr.2006.09.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 08/29/2006] [Accepted: 09/05/2006] [Indexed: 12/30/2022]
Abstract
Tubulin folding cofactors B (TBCB) and E (TBCE) are alpha-tubulin binding proteins that, together with Arl2 and cofactors D (TBCD), A (TBCA or p14) and C (TBCC), participate in tubulin biogenesis. TBCD and TBCE have also been implicated in microtubule dynamics through regulation of tubulin heterodimer dissociation. Understanding the in vivo function of these proteins will shed light on the Kenny-Caffey/Sanjad-Sakati syndrome, an important human disorder associated with TBCE. Here we show that, when overexpressed, TBCB depolymerizes microtubules. We found that this function is based on the ability of TBCB to form a binary complex with TBCE that greatly enhances the efficiency of this cofactor to dissociate tubulin in vivo and in vitro. We also show that TBCE, TBCB and alpha-tubulin form a ternary complex after heterodimer dissociation, whereas the free beta-tubulin subunit is recovered by TBCA. These complexes might serve to escort alpha-tubulin towards degradation or recycling, depending on the cell requirements.
Collapse
Affiliation(s)
- D Kortazar
- Unidad de Metabolómica, CICbioGUNE, Parque Tecnológico de Bizkaia, 48160-Derio, Spain
| | | | | | | | | | | | | |
Collapse
|
26
|
Miller RK, D'Silva S, Moore JK, Goodson HV. The CLIP-170 orthologue Bik1p and positioning the mitotic spindle in yeast. Curr Top Dev Biol 2006; 76:49-87. [PMID: 17118263 DOI: 10.1016/s0070-2153(06)76002-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Bik1p is the yeast Saccharomyces cerevisiae representative of the CLIP-170 family of microtubule plus-end tracking proteins. Bik1p shares a number of similarities with its mammalian counterpart CLIP-170, including an important role in dynein function. However, Bik1p and CLIP-170 differ in several significant ways, including the mechanisms utilized to track microtubule plus ends. In addition to presenting functional comparisons between Bik1p and CLIP-170, we provide sequence analyses that reveal previously unrecognized similarities between Bik1p and its animal counterparts. We examine in detail what is known about the functions of Bik1p and consider the various roles that Bik1p plays in positioning the yeast mitotic spindle. This chapter also highlights several recent findings, including the contribution of Bik1p to the yeast mating pathway.
Collapse
Affiliation(s)
- Rita K Miller
- Department of Biology, University of Rochester Rochester, New York 14627, USA
| | | | | | | |
Collapse
|
27
|
Abstract
The dynamic properties of microtubules are regulated by plus-end tracking proteins (+TIPs), which associate with the distal ends of microtubules. Among the +TIPs are cytoplasmic linker proteins (CLIPs), which promote microtubule growth and regulate dynein-dynactin localization, and CLIP-associating proteins (CLASPs), which stabilize specific subsets of microtubules on reception of signalling cues. CLIPs and CLASPs interact and cooperate to direct the microtubule network, thereby regulating cellular asymmetry.
Collapse
Affiliation(s)
- Niels Galjart
- Department of Cell Biology and Genetics, Erasmus Medical Centre, P.O. Box 1738, 3000 DR, Rotterdam, The Netherlands.
| |
Collapse
|
28
|
Bartolini F, Tian G, Piehl M, Cassimeris L, Lewis SA, Cowan NJ. Identification of a novel tubulin-destabilizing protein related to the chaperone cofactor E. J Cell Sci 2005; 118:1197-207. [PMID: 15728251 DOI: 10.1242/jcs.01719] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Factors that regulate the microtubule cytoskeleton are critical in determining cell behavior. Here we describe the function of a novel protein that we term E-like based on its sequence similarity to the tubulin-specific chaperone cofactor E. We find that upon overexpression, E-like depolymerizes microtubules by committing tubulin to proteosomal degradation. Our data suggest that this function is direct and is based on the ability of E-like to disrupt the tubulin heterodimer in vitro. Suppression of E-like expression results in an increase in the number of stable microtubules and a tight clustering of endocellular membranes around the microtubule-organizing center, while the properties of dynamic microtubules are unaffected. These observations define E-like as a novel regulator of tubulin stability, and provide a link between tubulin turnover and vesicle transport.
Collapse
Affiliation(s)
- Francesca Bartolini
- Department of Biochemistry, New York University Medical Center, 550 First Avenue, New York, NY 10016, USA
| | | | | | | | | | | |
Collapse
|
29
|
You L, Gillilan R, Huffaker TC. Model for the yeast cofactor A-beta-tubulin complex based on computational docking and mutagensis. J Mol Biol 2004; 341:1343-54. [PMID: 15321725 DOI: 10.1016/j.jmb.2004.06.081] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 06/24/2004] [Accepted: 06/29/2004] [Indexed: 11/16/2022]
Abstract
Virtually every biological process involves protein-protein contact but relatively few protein-protein complexes have been solved by X-ray crystallography. As more individual protein structures become available, computational methods are likely to play increasingly important roles in defining these interactions. Tubulin folding and dimer formation are complex processes requiring a variety of protein cofactors. One of these is cofactor A, which interacts with beta-tubulin prior to assembly of the alpha-tubulin-beta-tubulin heterodimer. In the yeast Saccharomyces cerevisiae, beta-tubulin is encoded by TUB2 and cofactor A by RBL2. We have used computational docking and site-directed mutagenesis to generate a model of the Rbl2-Tub2 complex from the solved structures of these two proteins. Residues in the N termini and the loops of the Rbl2 homodimer appear to mediate binding to beta-tubulin. These interact with beta-tubulin residues in the region that contains helices H9 and H10. Rbl2 and alpha-tubulin share overlapping binding sites on the beta-tubulin molecule providing a structural explanation for the mutually exclusive binding of Rbl2 and alpha-tubulin to beta-tubulin.
Collapse
Affiliation(s)
- Liru You
- Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | | | | |
Collapse
|
30
|
Saito K, Kigawa T, Koshiba S, Sato K, Matsuo Y, Sakamoto A, Takagi T, Shirouzu M, Yabuki T, Nunokawa E, Seki E, Matsuda T, Aoki M, Miyata Y, Hirakawa N, Inoue M, Terada T, Nagase T, Kikuno R, Nakayama M, Ohara O, Tanaka A, Yokoyama S. The CAP-Gly Domain of CYLD Associates with the Proline-Rich Sequence in NEMO/IKKγ. Structure 2004; 12:1719-28. [PMID: 15341735 DOI: 10.1016/j.str.2004.07.012] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2004] [Revised: 07/01/2004] [Accepted: 07/06/2004] [Indexed: 11/29/2022]
Abstract
CYLD was originally identified as the human familial cylindromatosis tumor suppressor. Recently, it was reported that CYLD directly interacts with NEMO/IKKgamma and TRAF2 in the NF-kappaB signaling pathway. The two proteins bind to a region of CYLD that contains a Cys-box motif and the third cytoskeleton-associated protein-glycine conserved (CAP-Gly) domain. Here we report that the third CAP-Gly domain of CYLD specifically interacts with one of the two proline-rich sequences of NEMO/IKKgamma. The tertiary structure of the CAP-Gly domain shares the five-stranded beta sheet topology with the SH3 domain, which is well known as a proline-rich sequence-recognition domain. However, chemical shift mapping revealed that the peptide binding site of the CAP-Gly domain is formed without the long peptide binding loop characteristic of the SH3 domain. Therefore, CAP-Gly is likely to be a novel proline-rich sequence binding domain with a mechanism different from that of the SH3 domain.
Collapse
Affiliation(s)
- Kohei Saito
- RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Lallemand-Breitenbach V, Quesnoit M, Braun V, El Marjou A, Poüs C, Goud B, Perez F. CLIPR-59 is a lipid raft-associated protein containing a cytoskeleton-associated protein glycine-rich domain (CAP-Gly) that perturbs microtubule dynamics. J Biol Chem 2004; 279:41168-78. [PMID: 15262990 DOI: 10.1074/jbc.m406482200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
We recently have identified a new cytoplasmic linker protein (CLIP), CLIPR-59, which is involved in the regulation of early endosome/trans-Golgi network dynamics. In contrast with CLIP-170, CLIPR-59 is not localized to microtubules at steady state but is associated with the trans-Golgi network and the plasma membrane. Here we show that the last 30 amino acids (C30) are sufficient for membrane targeting and that two cysteines in the C30 domain are palmitoylated. We demonstrate that CLIPR-59 is associated with lipid rafts via its C-terminal palmitoylated domain. In vitro experiments suggest that CLIPR-59 and its microtubule-binding domain alone have a better affinity for unpolymerized tubulin or small oligomers than for microtubules. In contrast with the CLIP-170 microtubule-binding domain, the CLIPR-59 microtubule-binding domain diminishes microtubule regrowth after nocodazole washout in vivo, showing that this domain can prevent microtubule polymerization. In contrast with the role of linker between membranes and microtubules that was proposed for CLIP function, CLIPR-59 thus may have an "anti-CLIP" function by preventing microtubule-raft interactions.
Collapse
|
32
|
Abstract
Cells require a properly oriented and organised microtubule array to transmit positional information. Recent data have revealed a heterogeneous population of microtubule-binding proteins that accumulates mainly at distal ends of polymerising microtubules. Two mechanisms may account for this concentration: transient immobilisation, which involves association of proteins with growing ends, followed by release more proximally; and deposition at ends via a molecular motor. As with lipid rafts, protein concentration at distal ends may allow a cascade of interactions in the restricted area of a microtubule plus end. This may, in turn, control the dynamic behaviour of this cytoskeletal network and its anchoring to other structures.
Collapse
Affiliation(s)
- Niels Galjart
- Department of Cell Biology and Genetics, Erasmus University, PO Box 1738, 3000 DR Rotterdam, The Netherlands.
| | | |
Collapse
|
33
|
Cowan NJ, Lewis SA. Type II chaperonins, prefoldin, and the tubulin-specific chaperones. ADVANCES IN PROTEIN CHEMISTRY 2002; 59:73-104. [PMID: 11868281 DOI: 10.1016/s0065-3233(01)59003-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- N J Cowan
- Department of Biochemistry, NYU Medical Center, New York, New York 10016, USA
| | | |
Collapse
|
34
|
Yin H, You L, Pasqualone D, Kopski KM, Huffaker TC. Stu1p is physically associated with beta-tubulin and is required for structural integrity of the mitotic spindle. Mol Biol Cell 2002; 13:1881-92. [PMID: 12058056 PMCID: PMC117611 DOI: 10.1091/mbc.01-09-0458] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Formation of the bipolar mitotic spindle relies on a balance of forces acting on the spindle poles. The primary outward force is generated by the kinesin-related proteins of the BimC family that cross-link antiparallel interpolar microtubules and slide them past each other. Here, we provide evidence that Stu1p is also required for the production of this outward force in the yeast Saccharomyces cerevisiae. In the temperature-sensitive stu1-5 mutant, spindle pole separation is inhibited, and preanaphase spindles collapse, with their previously separated poles being drawn together. The temperature sensitivity of stu1-5 can be suppressed by doubling the dosage of Cin8p, a yeast BimC kinesin-related protein. Stu1p was observed to be a component of the mitotic spindle localizing to the midregion of anaphase spindles. It also binds to microtubules in vitro, and we have examined the nature of this interaction. We show that Stu1p interacts specifically with beta-tubulin and identify the domains required for this interaction on both Stu1p and beta-tubulin. Taken together, these findings suggest that Stu1p binds to interpolar microtubules of the mitotic spindle and plays an essential role in their ability to provide an outward force on the spindle poles.
Collapse
Affiliation(s)
- Hongwei Yin
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853-2703, USA
| | | | | | | | | |
Collapse
|
35
|
Morgan JE, Gross JG, Pagel CN, Beauchamp JR, Fassati A, Thrasher AJ, Di Santo JP, Fisher IB, Shiwen X, Abraham DJ, Partridge TA. Myogenic cell proliferation and generation of a reversible tumorigenic phenotype are triggered by preirradiation of the recipient site. J Cell Biol 2002; 157:693-702. [PMID: 12011114 PMCID: PMC2173859 DOI: 10.1083/jcb.200108047] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Environmental influences have profound yet reversible effects on the behavior of resident cells. Earlier data have indicated that the amount of muscle formed from implanted myogenic cells is greatly augmented by prior irradiation (18 Gy) of the host mouse muscle. Here we confirm this phenomenon, showing that it varies between host mouse strains. However, it is unclear whether it is due to secretion of proliferative factors or reduction of antiproliferative agents. To investigate this further, we have exploited the observation that the immortal myogenic C2 C12 cell line forms tumors far more rapidly in irradiated than in nonirradiated host muscle. We show that the effect of preirradiation on tumor formation is persistent and dose dependent. However, C2 C12 cells are not irreversibly compelled to form undifferentiated tumor cells by the irradiated muscle environment and are still capable of forming large amounts of muscle when reimplanted into a nonirradiated muscle. In a clonal analysis of this effect, we discovered that C2 C12 cells have a bimodal propensity to form tumors; some clones form no tumors even after extensive periods in irradiated graft sites, whereas others rapidly form extensive tumors. This illustrates the subtle interplay between the phenotype of implanted cells and the factors in the muscle environment.
Collapse
MESH Headings
- Animals
- Cell Differentiation/physiology
- Cell Differentiation/radiation effects
- Cell Division/physiology
- Cell Division/radiation effects
- Cell Line, Transformed
- Cell Movement/drug effects
- Cell Movement/physiology
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Cell Transformation, Neoplastic/radiation effects
- Clone Cells/cytology
- Clone Cells/metabolism
- Clone Cells/radiation effects
- Dystrophin/deficiency
- Dystrophin/genetics
- Graft Survival/physiology
- Graft Survival/radiation effects
- Male
- Mice
- Mice, Inbred mdx
- Muscle, Skeletal/cytology
- Muscle, Skeletal/growth & development
- Muscle, Skeletal/radiation effects
- Neoplasms, Radiation-Induced/metabolism
- Neoplasms, Radiation-Induced/pathology
- Neoplasms, Radiation-Induced/physiopathology
- Phenotype
- Regeneration/physiology
- Regeneration/radiation effects
- Stem Cell Transplantation
- Stem Cells/cytology
- Stem Cells/metabolism
- Tissue Transplantation
Collapse
Affiliation(s)
- Jennifer E Morgan
- Muscle Cell Biology Group, Medical Research Council Clinical Sciences Centre, Faculty of Medicine, Imperial College School of Technology and Medicine, London W12 0NN, UK.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Abruzzi KC, Smith A, Chen W, Solomon F. Protection from free beta-tubulin by the beta-tubulin binding protein Rbl2p. Mol Cell Biol 2002; 22:138-47. [PMID: 11739729 PMCID: PMC134216 DOI: 10.1128/mcb.22.1.138-147.2002] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Free beta-tubulin not in heterodimers with alpha-tubulin can be toxic, disrupting microtubule assembly and function. We are interested in the mechanisms by which cells protect themselves from free beta-tubulin. This study focused specifically on the function of Rbl2p, which, like alpha-tubulin, can rescue cells from free beta-tubulin. In vitro studies of the mammalian homolog of Rbl2p, cofactor A, have suggested that Rbl2p/cofactor A may be involved in tubulin folding. Here we show that Rbl2p becomes essential in cells containing a modest excess of beta-tubulin relative to alpha-tubulin. However, this essential activity of Rbl2p/cofactorA does not depend upon the reactions described by the in vitro assay. Rescue of beta-tubulin toxicity requires a minimal but substoichiometric ratio of Rbl2p to beta-tubulin. The data suggest that Rbl2p binds transiently to free beta-tubulin, which then passes into an aggregated form that is not toxic.
Collapse
Affiliation(s)
- Katharine C Abruzzi
- Department of Biology and Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | | | |
Collapse
|
37
|
Nogales E. Structural insight into microtubule function. ANNUAL REVIEW OF BIOPHYSICS AND BIOMOLECULAR STRUCTURE 2001; 30:397-420. [PMID: 11441808 DOI: 10.1146/annurev.biophys.30.1.397] [Citation(s) in RCA: 258] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Microtubules are polymers that are essential for, among other functions, cell transport and cell division in all eukaryotes. The regulation of the microtubule system includes transcription of different tubulin isotypes, folding of alpha/beta-tubulin heterodimers, post-translation modification of tubulin, and nucleotide-based microtubule dynamics, as well as interaction with numerous microtubule-associated proteins that are themselves regulated. The result is the precise temporal and spatial pattern of microtubules that is observed throughout the cell cycle. The recent high-resolution analysis of the structure of tubulin and the microtubule has brought new insight to the study of microtubule function and regulation, as well as the mode of action of antimitotic drugs that disrupt normal microtubule behavior. The combination of structural, genetic, biochemical, and biophysical data should soon give us a fuller understanding of the exquisite details in the regulation of the microtubule cytoskeleton.
Collapse
Affiliation(s)
- E Nogales
- Department of Molecular and Cell Biology, University of California, Berkeley, and Lawrence Berkeley National Laboratory, Berkeley California 94720, USA.
| |
Collapse
|
38
|
Lopez-Fanarraga M, Avila J, Guasch A, Coll M, Zabala JC. Review: postchaperonin tubulin folding cofactors and their role in microtubule dynamics. J Struct Biol 2001; 135:219-29. [PMID: 11580271 DOI: 10.1006/jsbi.2001.4386] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The microtubule cytoskeleton consists of a highly organized network of microtubule polymers bound to their accessory proteins: microtubule-associated proteins, molecular motors, and microtubule-organizing proteins. The microtubule subunits are heterodimers composed of one alpha-tubulin polypeptide and one beta-tubulin polypeptide that should undergo a complex folding processing before they achieve a quaternary structure that will allow their incorporation into the polymer. Due to the extremely high protein concentration that exists at the cell cytoplasm, there are alpha- and beta-tubulin interacting proteins that prevent the unwanted interaction of these polypeptides with the surrounding protein pool during folding, thus allowing microtubule dynamics. Several years ago, the development of a nondenaturing electrophoretic technique made it possible to identify different tubulin intermediate complexes during tubulin biogenesis in vitro. By these means, the cytosolic chaperonin containing TCP-1 (CCT or TriC) and prefoldin have been demonstrated to intervene through tubulin and actin folding. Various other cofactors also identified along the alpha- and beta-tubulin postchaperonin folding route are now known to have additional roles in tubulin biogenesis such as participating in the synthesis, transport, and storage of alpha- and beta-tubulin. The future characterization of the tubulin-binding sites to these proteins, and perhaps other still unknown proteins, will help in the development of chemicals that could interfere with tubulin folding and thus modulating microtubule dynamics. In this paper, current knowledge of the above postchaperonin folding cofactors, which are in fact chaperones involved in tubulin heterodimer quaternary structure achievement, will be reviewed.
Collapse
Affiliation(s)
- M Lopez-Fanarraga
- Departamento de Biología Molecular-Unidad Asociada al Centro de Investigaciones Biológicas (CSIC), Universidad de Cantabria, Cardenal Herrera Oria s/n, Santander, 39011, Spain
| | | | | | | | | |
Collapse
|
39
|
Downing KH. Structural basis for the interaction of tubulin with proteins and drugs that affect microtubule dynamics. Annu Rev Cell Dev Biol 2001; 16:89-111. [PMID: 11031231 DOI: 10.1146/annurev.cellbio.16.1.89] [Citation(s) in RCA: 269] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The microtubule cytoskeleton is a highly regulated system. At different times in the cell cycle and positions within the organism, microtubules can be very stable or highly dynamic. Stability and dynamics are regulated by interaction with a large number of proteins that themselves may change at specific points in the cell cycle. Exogenous ligands can disrupt the normal processes by either increasing or decreasing microtubule stability and inhibiting their dynamic behavior. The recent determination of the structure of tubulin, the main component of microtubules, makes it possible now to begin to understand the details of these interactions. We review here the structure of the tubulin dimer, with particular regard to how proteins and drugs may bind and modulate microtubule dynamics.
Collapse
Affiliation(s)
- K H Downing
- Donner Laboratory, Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
| |
Collapse
|
40
|
Abstract
Microtubules are polymers that are essential for, among other functions, cell transport and cell division in all eukaryotes. The regulation of the microtubule system includes transcription of different tubulin isotypes, folding of /¿-tubulin heterodimers, post-translation modification of tubulin, and nucleotide-based microtubule dynamics, as well as interaction with numerous microtubule-associated proteins that are themselves regulated. The result is the precise temporal and spatial pattern of microtubules that is observed throughout the cell cycle. The recent high-resolution analysis of the structure of tubulin and the microtubule has brought new insight to the study of microtubule function and regulation, as well as the mode of action of antimitotic drugs that disrupt normal microtubule behavior. The combination of structural, genetic, biochemical, and biophysical data should soon give us a fuller understanding of the exquisite details in the regulation of the microtubule cytoskeleton.
Collapse
Affiliation(s)
- E Nogales
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA.
| |
Collapse
|
41
|
Abstract
Overexpression of the beta-tubulin binding protein Rbl2p/cofactor A is lethal in yeast cells expressing a mutant alpha-tubulin, tub1-724, that produces unstable heterodimer. Here we use RBL2 overexpression to identify mutations in other genes that affect formation or stability of heterodimer. This approach identifies four genes-CIN1, CIN2, CIN4, and PAC2-as affecting heterodimer formation in vivo. The vertebrate homologues of two of these gene products-Cin1p/cofactor D and Pac2p/cofactor E-can catalyze exchange of tubulin polypeptides into preexisting heterodimer in vitro. Previous work suggests that both Cin2p or Cin4p act in concert with Cin1p in yeast, but no role for vertebrate homologues of either has been reported in the in vitro reaction. Results presented here demonstrate that these proteins can promote heterodimer formation in vivo. RBL2 overexpression in cin1 and pac2 mutant cells causes microtubule disassembly and enhanced formation of Rbl2p-beta-tubulin complex, as it does in the alpha-tubulin mutant that produces weakened heterodimer. Significantly, excess Cin1p/cofactor D suppresses the conditional phenotypes of that mutant alpha-tubulin. Although none of the four genes is essential for viability under normal conditions, they become essential under conditions where the levels of dissociated tubulin polypeptides increase. Therefore, these proteins may provide a salvage pathway for dissociated tubulin heterodimers and so rescue cells from the deleterious effects of free beta-tubulin.
Collapse
Affiliation(s)
- J A Fleming
- Department of Biology and Center for Cancer Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | | | | |
Collapse
|
42
|
Radcliffe PA, Garcia MA, Toda T. The cofactor-dependent pathways for alpha- and beta-tubulins in microtubule biogenesis are functionally different in fission yeast. Genetics 2000; 156:93-103. [PMID: 10978278 PMCID: PMC1461245 DOI: 10.1093/genetics/156.1.93] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The biogenesis of microtubules in the cell comprises a series of complex steps, including protein-folding reactions catalyzed by chaperonins. In addition a group of evolutionarily conserved proteins, called cofactors (A to E), is required for the production of assembly-competent alpha-/beta-tubulin heterodimers. Using fission yeast, in which alp11(+), alp1(+), and alp21(+), encoding the homologs for cofactors B, D, and E, respectively, are essential for cell viability, we have undertaken the genetic analysis of alp31(+), the homolog of cofactor A. Gene disruption analysis shows that, unlike the three genes mentioned above, alp31(+) is dispensable for cell growth and division. Nonetheless, detailed analysis of alp31-deleted cells demonstrates that Alp31(A) is required for the maintenance of microtubule structures and, consequently, the proper control of growth polarity. alp31-deleted cells show genetic interactions with mutations in beta-tubulin, but not in alpha-tubulin. Budding yeast cofactor A homolog RBL2 is capable of suppressing the polarity defects of alp31-deleted cells. We conclude that the cofactor-dependent biogenesis of microtubules comprises an essential and a nonessential pathway, both of which are required for microtubule integrity.
Collapse
Affiliation(s)
- P A Radcliffe
- Laboratory of Cell Regulation, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom
| | | | | |
Collapse
|
43
|
Grava S, Dumoulin P, Madania A, Tarassov I, Winsor B. Functional analysis of six genes from chromosomes XIV and XV of Saccharomyces cerevisiae reveals YOR145c as an essential gene and YNL059c/ARP5 as a strain-dependent essential gene encoding nuclear proteins. Yeast 2000; 16:1025-33. [PMID: 10923024 DOI: 10.1002/1097-0061(200008)16:11<1025::aid-yea602>3.0.co;2-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
We report here basic functional analysis of strains deleted for six open reading frames (ORFs), YNL059c and YNL148c from chromosome XIV and YOR145c, YOR152c, YOR161c and YOR162c from chromosome XV of Saccharomyces cerevisiae. ORFs were replaced with the KanMX4 resistance marker using a long flanking homology PCR strategy in FY1679 and W303 diploid strains. Replacement cassettes were constructed in plasmid pUG7 and the cognate wild-type genes were recovered by gap repair. Sporulation and tetrad analysis revealed that deletion of YNL059c/ARP5 was lethal for vegetative growth in strain W303 and caused severe growth defects in strain FY1679 while YOR145c was essential for growth in both strains. Fusion of the green fluorescent protein (GFP) gene to the 3' ends of the YNL059c/ARP5 and YOR145c coding sequences created functional chimeric genes at the respective chromosomal loci. Both Arp5-GFP and Yor145-GFP localized to the nucleus, Yor145-GFP concentrating in the nucleolus. The vectors containing the deletion cassettes and the cognate wild-type genes, the oligonucleotides, and the deletant strains are available from the EUROFAN resource centre EUROSCARF (Frankfurt).
Collapse
Affiliation(s)
- S Grava
- Mécanismes Moléculaires de la Division Cellulaire et du Développement, UPR 9005 du CNRS, IBMC, 15 rue Descartes, F-67084 Strasbourg, France
| | | | | | | | | |
Collapse
|
44
|
Hoogenraad CC, Akhmanova A, Grosveld F, De Zeeuw CI, Galjart N. Functional analysis of CLIP-115 and its binding to microtubules. J Cell Sci 2000; 113 ( Pt 12):2285-97. [PMID: 10825300 DOI: 10.1242/jcs.113.12.2285] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytoplasmic linker proteins (CLIPs) bind to microtubules and are proposed to link this cytoskeletal network to other intracellular structures. We are interested in CLIP-115, since this protein is enriched in neuronal dendrites and may operate in the control of brain-specific organelle translocations. Each CLIP monomer is characterized by two microtubule-binding (MTB) motifs, surrounded by basic, serine-rich regions. This head domain is connected to the C-terminal tail through a long coiled-coil structure. The MTB domains are conserved as a single domain in other proteins involved in microtubule based transport and dynamics, such as p150(Glued). Here we provide evidence that efficient binding of CLIP-115 to microtubules is sensitive to phosphorylation and is not mediated by the conserved MTB domains alone, but requires the presence of the basic, serine rich regions in addition to the MTB motifs. In transfected COS-1 cells, CLIP-115 initially accumulates at the distal ends of microtubules and coincides with CLIP-170, indicating that both proteins mark growing microtubule ends. However, when expressed at higher levels, CLIP-115 and -170 affect the microtubule network differently. This might be partly due to the divergent C-termini of the two proteins. We demonstrate that, similar to CLIP-170, CLIP-115 forms homodimers, which, at least in vitro, are linked by disulfide bridges. Cysteine(391) of CLIP-115, however, is specific in that it controls the microtubule bundling capacity of certain mutant CLIP-115 molecules. Therefore, both similar and specific mechanisms appear to regulate the conformation of CLIPs as well as their binding to microtubules.
Collapse
Affiliation(s)
- C C Hoogenraad
- MGC Department of Cell Biology and Genetics and Department of Anatomy, Erasmus University, PO Box 1738, The Netherlands
| | | | | | | | | |
Collapse
|
45
|
Bhamidipati A, Lewis SA, Cowan NJ. ADP ribosylation factor-like protein 2 (Arl2) regulates the interaction of tubulin-folding cofactor D with native tubulin. J Cell Biol 2000; 149:1087-96. [PMID: 10831612 PMCID: PMC2174823 DOI: 10.1083/jcb.149.5.1087] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The ADP ribosylation factor-like proteins (Arls) are a family of small monomeric G proteins of unknown function. Here, we show that Arl2 interacts with the tubulin-specific chaperone protein known as cofactor D. Cofactors C, D, and E assemble the alpha/beta- tubulin heterodimer and also interact with native tubulin, stimulating it to hydrolyze GTP and thus acting together as a beta-tubulin GTPase activating protein (GAP). We find that Arl2 downregulates the tubulin GAP activity of C, D, and E, and inhibits the binding of D to native tubulin in vitro. We also find that overexpression of cofactors D or E in cultured cells results in the destruction of the tubulin heterodimer and of microtubules. Arl2 specifically prevents destruction of tubulin and microtubules by cofactor D, but not by cofactor E. We generated mutant forms of Arl2 based on the known properties of classical Ras-family mutations. Experiments using these altered forms of Arl2 in vitro and in vivo demonstrate that it is GDP-bound Arl2 that interacts with cofactor D, thereby averting tubulin and microtubule destruction. These data establish a role for Arl2 in modulating the interaction of tubulin-folding cofactors with native tubulin in vivo.
Collapse
Affiliation(s)
- Arunashree Bhamidipati
- Department of Biochemistry, New York University Medical Center, New York, New York 10016
| | - Sally A. Lewis
- Department of Biochemistry, New York University Medical Center, New York, New York 10016
| | - Nicholas J. Cowan
- Department of Biochemistry, New York University Medical Center, New York, New York 10016
| |
Collapse
|
46
|
Richards KL, Anders KR, Nogales E, Schwartz K, Downing KH, Botstein D. Structure-function relationships in yeast tubulins. Mol Biol Cell 2000; 11:1887-903. [PMID: 10793159 PMCID: PMC14891 DOI: 10.1091/mbc.11.5.1887] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A comprehensive set of clustered charged-to-alanine mutations was generated that systematically alter TUB1, the major alpha-tubulin gene of Saccharomyces cerevisiae. A variety of phenotypes were observed, including supersensitivity and resistance to the microtubule-destabilizing drug benomyl, lethality, and cold- and temperature-sensitive lethality. Many of the most benomyl-sensitive tub1 alleles were synthetically lethal in combination with tub3Delta, supporting the idea that benomyl supersensitivity is a rough measure of microtubule instability and/or insufficiency in the amount of alpha-tubulin. The systematic tub1 mutations were placed, along with the comparable set of tub2 mutations previously described, onto a model of the yeast alpha-beta-tubulin dimer based on the three-dimensional structure of bovine tubulin. The modeling revealed a potential site for binding of benomyl in the core of beta-tubulin. Residues whose mutation causes cold sensitivity were concentrated at the lateral and longitudinal interfaces between adjacent subunits. Residues that affect binding of the microtubule-binding protein Bim1p form a large patch across the exterior-facing surface of alpha-tubulin in the model. Finally, the positions of the mutations suggest that proximity to the alpha-beta interface may account for the finding of synthetic lethality of five viable tub1 alleles with the benomyl-resistant but otherwise entirely viable tub2-201 allele.
Collapse
Affiliation(s)
- K L Richards
- Department of Genetics, Stanford University School of Medicine, Stanford, California 94305, USA
| | | | | | | | | | | |
Collapse
|
47
|
Radcliffe PA, Hirata D, Vardy L, Toda T. Functional dissection and hierarchy of tubulin-folding cofactor homologues in fission yeast. Mol Biol Cell 1999; 10:2987-3001. [PMID: 10473641 PMCID: PMC25543 DOI: 10.1091/mbc.10.9.2987] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
We describe the isolation of fission yeast homologues of tubulin-folding cofactors B (Alp11) and E (Alp21), which are essential for cell viability and the maintenance of microtubules. Alp11(B) contains the glycine-rich motif (the CLIP-170 domain) involved in microtubular functions, whereas, unlike mammalian cofactor E, Alp21(E) does not. Both mammalian and yeast cofactor E, however, do contain leucine-rich repeats. Immunoprecipitation analysis shows that Alp11(B) interacts with both alpha-tubulin and Alp21(E), but not with the cofactor D homologue Alp1, whereas Alp21(E) also interacts with Alp1(D). The cellular amount of alpha-tubulin is decreased in both alp1 and alp11 mutants. Overproduction of Alp11(B) results in cell lethality and the disappearance of microtubules, which is rescued by co-overproduction of alpha-tubulin. Both full-length Alp11(B) and the C-terminal third containing the CLIP-170 domain localize in the cytoplasm, and this domain is required for efficient binding to alpha-tubulin. Deletion of alp11 is suppressed by multicopy plasmids containing either alp21(+) or alp1(+), whereas alp21 deletion is rescued by overexpression of alp1(+) but not alp11(+). Finally, the alp1 mutant is not complemented by either alp11(+) or alp21(+). The results suggest that cofactors operate in a linear pathway (Alp11(B)-Alp21(E)-Alp1(D)), each with distinct roles.
Collapse
Affiliation(s)
- P A Radcliffe
- Laboratory of Cell Regulation, Imperial Cancer Research Fund, London WC2A 3PX, United Kingdom
| | | | | | | |
Collapse
|