1
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Meier SM, Steinmetz MO, Barral Y. Microtubule specialization by +TIP networks: from mechanisms to functional implications. Trends Biochem Sci 2024; 49:318-332. [PMID: 38350804 DOI: 10.1016/j.tibs.2024.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/23/2023] [Accepted: 01/12/2024] [Indexed: 02/15/2024]
Abstract
To fulfill their actual cellular role, individual microtubules become functionally specialized through a broad range of mechanisms. The 'search and capture' model posits that microtubule dynamics and functions are specified by cellular targets that they capture (i.e., a posteriori), independently of the microtubule-organizing center (MTOC) they emerge from. However, work in budding yeast indicates that MTOCs may impart a functional identity to the microtubules they nucleate, a priori. Key effectors in this process are microtubule plus-end tracking proteins (+TIPs), which track microtubule tips to regulate their dynamics and facilitate their targeted interactions. In this review, we discuss potential mechanisms of a priori microtubule specialization, focusing on recent findings indicating that +TIP networks may undergo liquid biomolecular condensation in different cell types.
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Affiliation(s)
- Sandro M Meier
- Institute of Biochemistry, Department of Biology, and Bringing Materials to Life Initiative, ETH Zürich, Switzerland; Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen, Switzerland; Bringing Materials to Life Initiative, ETH Zürich, Switzerland
| | - Michel O Steinmetz
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen, Switzerland; University of Basel, Biozentrum, CH-4056 Basel, Switzerland.
| | - Yves Barral
- Institute of Biochemistry, Department of Biology, and Bringing Materials to Life Initiative, ETH Zürich, Switzerland; Bringing Materials to Life Initiative, ETH Zürich, Switzerland.
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2
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Volkov VA, Akhmanova A. Phase separation on microtubules: from droplet formation to cellular function? Trends Cell Biol 2024; 34:18-30. [PMID: 37453878 DOI: 10.1016/j.tcb.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/18/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
Microtubules are cytoskeletal polymers that play important roles in numerous cellular processes, ranging from the control of cell shape and polarity to cell division and intracellular transport. Many of these roles rely on proteins that bind to microtubule ends and shafts, carry intrinsically disordered regions, and form complex multivalent interaction networks. A flurry of recent studies demonstrated that these properties allow diverse microtubule-binding proteins to undergo liquid-liquid phase separation (LLPS) in vitro. It is proposed that LLPS could potentially affect multiple microtubule-related processes, such as microtubule nucleation, control of microtubule dynamics and organization, and microtubule-based transport. Here, we discuss the evidence in favor and against the occurrence of LLPS and its functional significance for microtubule-based processes in cells.
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Affiliation(s)
- Vladimir A Volkov
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, E1 4NS, UK.
| | - Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584 CH, The Netherlands.
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3
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Lawrence EJ, Chatterjee S, Zanic M. More is different: Reconstituting complexity in microtubule regulation. J Biol Chem 2023; 299:105398. [PMID: 37898404 PMCID: PMC10694663 DOI: 10.1016/j.jbc.2023.105398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 10/13/2023] [Accepted: 10/18/2023] [Indexed: 10/30/2023] Open
Abstract
Microtubules are dynamic cytoskeletal filaments that undergo stochastic switching between phases of polymerization and depolymerization-a behavior known as dynamic instability. Many important cellular processes, including cell motility, chromosome segregation, and intracellular transport, require complex spatiotemporal regulation of microtubule dynamics. This coordinated regulation is achieved through the interactions of numerous microtubule-associated proteins (MAPs) with microtubule ends and lattices. Here, we review the recent advances in our understanding of microtubule regulation, focusing on results arising from biochemical in vitro reconstitution approaches using purified multiprotein ensembles. We discuss how the combinatory effects of MAPs affect both the dynamics of individual microtubule ends, as well as the stability and turnover of the microtubule lattice. In addition, we highlight new results demonstrating the roles of protein condensates in microtubule regulation. Our overall intent is to showcase how lessons learned from reconstitution approaches help unravel the regulatory mechanisms at play in complex cellular environments.
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Affiliation(s)
- Elizabeth J Lawrence
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Saptarshi Chatterjee
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Marija Zanic
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee, USA; Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA.
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4
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Song X, Yang F, Yang T, Wang Y, Ding M, Li L, Xu P, Liu S, Dai M, Chi C, Xiang S, Xu C, Li D, Wang Z, Li L, Hill DL, Fu C, Yuan K, Li P, Zang J, Hou Z, Jiang K, Shi Y, Liu X, Yao X. Phase separation of EB1 guides microtubule plus-end dynamics. Nat Cell Biol 2023; 25:79-91. [PMID: 36536176 DOI: 10.1038/s41556-022-01033-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 10/21/2022] [Indexed: 12/24/2022]
Abstract
In eukaryotes, end-binding (EB) proteins serve as a hub for orchestrating microtubule dynamics and are essential for cellular dynamics and organelle movements. EB proteins modulate structural transitions at growing microtubule ends by recognizing and promoting an intermediate state generated during GTP hydrolysis. However, the molecular mechanisms and physiochemical properties of the EB1 interaction network remain elusive. Here we show that EB1 formed molecular condensates through liquid-liquid phase separation (LLPS) to constitute the microtubule plus-end machinery. EB1 LLPS is driven by multivalent interactions among different segments, which are modulated by charged residues in the linker region. Phase-separated EB1 provided a compartment for enriching tubulin dimers and other plus-end tracking proteins. Real-time imaging of chromosome segregation in HeLa cells expressing LLPS-deficient EB1 mutants revealed the importance of EB1 LLPS dynamics in mitotic chromosome movements. These findings demonstrate that EB1 forms a distinct physical and biochemical membraneless-organelle via multivalent interactions that guide microtubule dynamics.
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Affiliation(s)
- Xiaoyu Song
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China.,Keck Center for Organoids Plasticity, Morehouse School of Medicine, Atlanta, GA, USA
| | - Fengrui Yang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China.,Keck Center for Organoids Plasticity, Morehouse School of Medicine, Atlanta, GA, USA
| | - Tongtong Yang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Yong Wang
- Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Wuhan University, Wuhan, China
| | - Mingrui Ding
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China.,Keck Center for Organoids Plasticity, Morehouse School of Medicine, Atlanta, GA, USA
| | - Linge Li
- Anhui Key Laboratory for Chemical Biology & Hefei National Center for Cross-disciplinary Sciences, Hefei, China
| | - Panpan Xu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Shuaiyu Liu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China.,Anhui Key Laboratory for Chemical Biology & Hefei National Center for Cross-disciplinary Sciences, Hefei, China
| | - Ming Dai
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Changbiao Chi
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Shengqi Xiang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Chao Xu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Dong Li
- Institute of Biophysics, Beijing, China
| | - Zhikai Wang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China.,Keck Center for Organoids Plasticity, Morehouse School of Medicine, Atlanta, GA, USA
| | - Lin Li
- CAS Center of Excellence in Molecular Cell Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Donald L Hill
- Department of Pathology, University of Alabama, Birmingham, AL, USA
| | - Chuanhai Fu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Kai Yuan
- Hunan Key Laboratory of Molecular Precision Medicine, Central South University School of Life Sciences, Changsha, China
| | - Pilong Li
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Jianye Zang
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Zhonghuai Hou
- Anhui Key Laboratory for Chemical Biology & Hefei National Center for Cross-disciplinary Sciences, Hefei, China
| | - Kai Jiang
- Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Wuhan University, Wuhan, China
| | - Yunyu Shi
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China
| | - Xing Liu
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China. .,Keck Center for Organoids Plasticity, Morehouse School of Medicine, Atlanta, GA, USA.
| | - Xuebiao Yao
- MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Center for Cross-disciplinary Sciences, University of Science & Technology of China School of Life Sciences, Hefei, China.
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5
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Miryala CSJ, Holland ED, Dent EW. Contributions of microtubule dynamics and transport to presynaptic and postsynaptic functions. Mol Cell Neurosci 2022; 123:103787. [PMID: 36252720 PMCID: PMC9838116 DOI: 10.1016/j.mcn.2022.103787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/07/2022] [Accepted: 10/11/2022] [Indexed: 11/27/2022] Open
Abstract
Microtubules (MT) are elongated, tubular, cytoskeletal structures formed from polymerization of tubulin dimers. They undergo continuous cycles of polymerization and depolymerization, primarily at their plus ends, termed dynamic instability. Although this is an intrinsic property of MTs, there are a myriad of MT-associated proteins that function in regulating MT dynamic instability and other dynamic processes that shape the MT array. Additionally, MTs assemble into long, semi-rigid structures which act as substrates for long-range, motor-driven transport of many different types of cargoes throughout the cell. Both MT dynamics and motor-based transport play important roles in the function of every known type of cell. Within the last fifteen years many groups have shown that MT dynamics and transport play ever-increasing roles in the neuronal function of mature neurons. Not only are neurons highly polarized cells, but they also connect with one another through synapses to form complex networks. Here we will focus on exciting studies that have illuminated how MTs function both pre-synaptically in axonal boutons and post-synaptically in dendritic spines. It is becoming clear that MT dynamics and transport both serve important functions in synaptic plasticity. Thus, it is not surprising that disruption of MTs, either through hyperstabilization or destabilization, has profound consequences for learning and memory. Together, the studies described here suggest that MT dynamics and transport play key roles in synaptic function and when disrupted result in compromised learning and memory.
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Affiliation(s)
- Chandra S. J. Miryala
- Department of Neuroscience, University of Wisconsin, School of Medicine and Public Health, Madison, WI 53705
| | - Elizabeth D. Holland
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705
| | - Erik W. Dent
- Department of Neuroscience, University of Wisconsin, School of Medicine and Public Health, Madison, WI 53705,Corresponding Author: Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705,
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6
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Park EA, Kim J, Shin MY, Park SJ. Kinesin-13, a Motor Protein, is Regulated by Polo-like Kinase in Giardia lamblia. THE KOREAN JOURNAL OF PARASITOLOGY 2022; 60:163-172. [PMID: 35772734 PMCID: PMC9256289 DOI: 10.3347/kjp.2022.60.3.163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 06/15/2023]
Abstract
Kinesin-13 (Kin-13), a depolymerizer of microtubule (MT), has been known to affect the length of Giardia. Giardia Kin-13 (GlKin-13) was localized to axoneme, flagellar tips, and centrosomes, where phosphorylated forms of Giardia polo-like kinase (GlPLK) were distributed. We observed the interaction between GlKin-13 and GlPLK via co-immunoprecipitation using transgenic Giardia cells expressing Myc-tagged GlKin-13, hemagglutinin-tagged GlPLK, and in vitro-synthesized GlKin-13 and GlPLK proteins. In vitro-synthesized GlPLK was demonstrated to auto-phosphorylate and phosphorylate GlKin-13 upon incubation with [γ-32P]ATP. Morpholino-mediated depletion of both GlKin-13 and GlPLK caused an extension of flagella and a decreased volume of median bodies in Giardia trophozoites. Our results suggest that GlPLK plays a pertinent role in formation of flagella and median bodies by modulating MT depolymerizing activity of GlKin-13.
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7
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Wu YFO, Bryant AT, Nelson NT, Madey AG, Fernandes GF, Goodson HV. Overexpression of the microtubule-binding protein CLIP-170 induces a +TIP network superstructure consistent with a biomolecular condensate. PLoS One 2021; 16:e0260401. [PMID: 34890409 PMCID: PMC8664194 DOI: 10.1371/journal.pone.0260401] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 11/09/2021] [Indexed: 12/02/2022] Open
Abstract
Proper regulation of microtubule (MT) dynamics is critical for cellular processes including cell division and intracellular transport. Plus-end tracking proteins (+TIPs) dynamically track growing MTs and play a key role in MT regulation. +TIPs participate in a complex web of intra- and inter- molecular interactions known as the +TIP network. Hypotheses addressing the purpose of +TIP:+TIP interactions include relieving +TIP autoinhibition and localizing MT regulators to growing MT ends. In addition, we have proposed that the web of +TIP:+TIP interactions has a physical purpose: creating a dynamic scaffold that constrains the structural fluctuations of the fragile MT tip and thus acts as a polymerization chaperone. Here we examine the possibility that this proposed scaffold is a biomolecular condensate (i.e., liquid droplet). Many animal +TIP network proteins are multivalent and have intrinsically disordered regions, features commonly found in biomolecular condensates. Moreover, previous studies have shown that overexpression of the +TIP CLIP-170 induces large “patch” structures containing CLIP-170 and other +TIPs; we hypothesized that these structures might be biomolecular condensates. To test this hypothesis, we used video microscopy, immunofluorescence staining, and Fluorescence Recovery After Photobleaching (FRAP). Our data show that the CLIP-170-induced patches have hallmarks indicative of a biomolecular condensate, one that contains +TIP proteins and excludes other known condensate markers. Moreover, bioinformatic studies demonstrate that the presence of intrinsically disordered regions is conserved in key +TIPs, implying that these regions are functionally significant. Together, these results indicate that the CLIP-170 induced patches in cells are phase-separated liquid condensates and raise the possibility that the endogenous +TIP network might form a liquid droplet at MT ends or other +TIP locations.
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Affiliation(s)
- Yueh-Fu O. Wu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States of America
- Integrated Biomedical Sciences Graduate Program, University of Notre Dame, Notre Dame, IN, United States of America
| | - Annamarie T. Bryant
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States of America
- Integrated Biomedical Sciences Graduate Program, University of Notre Dame, Notre Dame, IN, United States of America
| | - Nora T. Nelson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States of America
| | - Alexander G. Madey
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States of America
| | - Gail F. Fernandes
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States of America
| | - Holly V. Goodson
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States of America
- Integrated Biomedical Sciences Graduate Program, University of Notre Dame, Notre Dame, IN, United States of America
- Department of Biological Sciences, University of Notre Dame, Notre Dame, IN, United States of America
- * E-mail:
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8
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Urazbaev A, Serikbaeva A, Tvorogova A, Dusenbayev A, Kauanova S, Vorobjev I. On the Relationship Between EB-3 Profiles and Microtubules Growth in Cultured Cells. Front Mol Biosci 2021; 8:745089. [PMID: 34820422 PMCID: PMC8606533 DOI: 10.3389/fmolb.2021.745089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022] Open
Abstract
Microtubules are dynamic structures undergoing rapid growth and shrinkage in living cells and in vitro. The growth of microtubules in vitro was analyzed with subpixel precision (Maurer et al., Current Biology, 2014, 24 (4), 372-384); however, to what extent these results could be applied for microtubules growing in vivo remains largely unknown. Particularly, the question is whether microtubule growth velocity in cells could be sufficiently approximated by a Gaussian distribution or its variability requires a more sophisticated description? Addressing this question, we used time-lapse microscopy and mathematical modeling, and we analyzed EB-3 comets forming on microtubules of cultured cells with subpixel precision. Parameters of comets (shape, form, and velocity) were used as topological characteristics of 3D voxel objects. Using regression analysis, we determined the real positions of the microtubule tips in time-lapse sequences. By exponential decay fitting of the restored comet intensity profile, we found that in vivo EB-3 rapidly exchanges on growing microtubule ends with a decoration time ∼ 2 s. We next developed the model showing that the best correlation between comet length and microtubule end growth velocity is at time intervals close to the decoration time. In the cells, EB comet length positively correlates with microtubule growth velocity in preceding time intervals, while demonstrating no correlation in subsequent time intervals. Correlation between comet length and instantaneous growth velocity of microtubules remains under nocodazole treatment when mean values of both parameters decrease. Our data show that the growth of microtubules in living cells is well-approximated by a constant velocity with large stochastic fluctuations.
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Affiliation(s)
- Arshat Urazbaev
- National Laboratory Astana, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Anara Serikbaeva
- Laboratory of Biophotonics and Imaging, National Laboratory Astana, Nazarbayev University, Nur-Sultan, Kazakhstan.,Department of Physiology and Biophysics (M/C 901), University of Illinois at Chicago, Chicago, IL, United States
| | - Anna Tvorogova
- A.N.Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Azamat Dusenbayev
- National Laboratory Astana, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Sholpan Kauanova
- Laboratory of Biophotonics and Imaging, National Laboratory Astana, Nazarbayev University, Nur-Sultan, Kazakhstan.,Department of Biology, School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, Kazakhstan
| | - Ivan Vorobjev
- Laboratory of Biophotonics and Imaging, National Laboratory Astana, Nazarbayev University, Nur-Sultan, Kazakhstan.,A.N.Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Department of Biology, School of Sciences and Humanities, Nazarbayev University, Nur-Sultan, Kazakhstan
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9
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CTCF chromatin residence time controls three-dimensional genome organization, gene expression and DNA methylation in pluripotent cells. Nat Cell Biol 2021; 23:881-893. [PMID: 34326481 DOI: 10.1038/s41556-021-00722-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 06/24/2021] [Indexed: 12/12/2022]
Abstract
The 11 zinc finger (ZF) protein CTCF regulates topologically associating domain formation and transcription through selective binding to thousands of genomic sites. Here, we replaced endogenous CTCF in mouse embryonic stem cells with green-fluorescent-protein-tagged wild-type or mutant proteins lacking individual ZFs to identify additional determinants of CTCF positioning and function. While ZF1 and ZF8-ZF11 are not essential for cell survival, ZF8 deletion strikingly increases the DNA binding off-rate of mutant CTCF, resulting in reduced CTCF chromatin residence time. Loss of ZF8 results in widespread weakening of topologically associating domains, aberrant gene expression and increased genome-wide DNA methylation. Thus, important chromatin-templated processes rely on accurate CTCF chromatin residence time, which we propose depends on local sequence and chromatin context as well as global CTCF protein concentration.
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10
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Chan ZCK, Kwan HLR, Wong YS, Jiang Z, Zhou Z, Tam KW, Chan YS, Chan CB, Lee CW. Site-directed MT1-MMP trafficking and surface insertion regulate AChR clustering and remodeling at developing NMJs. eLife 2020; 9:54379. [PMID: 32208136 PMCID: PMC7093154 DOI: 10.7554/elife.54379] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 02/10/2020] [Indexed: 12/12/2022] Open
Abstract
At vertebrate neuromuscular junctions (NMJs), the synaptic basal lamina contains different extracellular matrix (ECM) proteins and synaptogenic factors that induce and maintain synaptic specializations. Here, we report that podosome-like structures (PLSs) induced by ubiquitous ECM proteins regulate the formation and remodeling of acetylcholine receptor (AChR) clusters via focal ECM degradation. Mechanistically, ECM degradation is mediated by PLS-directed trafficking and surface insertion of membrane-type 1 matrix metalloproteinase (MT1-MMP) to AChR clusters through microtubule-capturing mechanisms. Upon synaptic induction, MT1-MMP plays a crucial role in the recruitment of aneural AChR clusters for the assembly of postsynaptic specializations. Lastly, the structural defects of NMJs in embryonic MT1-MMP-/- mice further demonstrate the physiological role of MT1-MMP in normal NMJ development. Collectively, this study suggests that postsynaptic MT1-MMP serves as a molecular switch to synaptogenesis by modulating local ECM environment for the deposition of synaptogenic signals that regulate postsynaptic differentiation at developing NMJs.
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Affiliation(s)
- Zora Chui-Kuen Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Hiu-Lam Rachel Kwan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Yin Shun Wong
- School of Biological Sciences, Faculty of Science, The University of Hong Kong, Hong Kong, China
| | - Zhixin Jiang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Zhongjun Zhou
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kin Wai Tam
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Ying-Shing Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Chi Bun Chan
- School of Biological Sciences, Faculty of Science, The University of Hong Kong, Hong Kong, China
| | - Chi Wai Lee
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
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11
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Rodríguez-García R, Volkov VA, Chen CY, Katrukha EA, Olieric N, Aher A, Grigoriev I, López MP, Steinmetz MO, Kapitein LC, Koenderink G, Dogterom M, Akhmanova A. Mechanisms of Motor-Independent Membrane Remodeling Driven by Dynamic Microtubules. Curr Biol 2020; 30:972-987.e12. [PMID: 32032506 PMCID: PMC7090928 DOI: 10.1016/j.cub.2020.01.036] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 12/09/2019] [Accepted: 01/10/2020] [Indexed: 12/26/2022]
Abstract
Microtubule-dependent organization of membranous organelles occurs through motor-based pulling and by coupling microtubule dynamics to membrane remodeling. For example, tubules of endoplasmic reticulum (ER) can be extended by kinesin- and dynein-mediated transport and through the association with the tips of dynamic microtubules. The binding between ER and growing microtubule plus ends requires End Binding (EB) proteins and the transmembrane protein STIM1, which form a tip-attachment complex (TAC), but it is unknown whether these proteins are sufficient for membrane remodeling. Furthermore, EBs and their partners undergo rapid turnover at microtubule ends, and it is unclear how highly transient protein-protein interactions can induce load-bearing processive motion. Here, we reconstituted membrane tubulation in a minimal system with giant unilamellar vesicles, dynamic microtubules, an EB protein, and a membrane-bound protein that can interact with EBs and microtubules. We showed that these components are sufficient to drive membrane remodeling by three mechanisms: membrane tubulation induced by growing microtubule ends, motor-independent membrane sliding along microtubule shafts, and membrane pulling by shrinking microtubules. Experiments and modeling demonstrated that the first two mechanisms can be explained by adhesion-driven biased membrane spreading on microtubules. Optical trapping revealed that growing and shrinking microtubule ends can exert forces of ∼0.5 and ∼5 pN, respectively, through attached proteins. Rapidly exchanging molecules that connect membranes to dynamic microtubules can thus bear a sufficient load to induce membrane deformation and motility. Furthermore, combining TAC components and a membrane-attached kinesin in the same in vitro assays demonstrated that they can cooperate in promoting membrane tubule extension.
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Affiliation(s)
- Ruddi Rodríguez-García
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584, the Netherlands
| | - Vladimir A Volkov
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, Delft 2629, the Netherlands
| | - Chiung-Yi Chen
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584, the Netherlands
| | - Eugene A Katrukha
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584, the Netherlands
| | - Natacha Olieric
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Forschungsstrasse 111, Villigen 5232, Switzerland
| | - Amol Aher
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584, the Netherlands
| | - Ilya Grigoriev
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584, the Netherlands
| | | | - Michel O Steinmetz
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Forschungsstrasse 111, Villigen 5232, Switzerland; University of Basel, Biozentrum, Klingelbergstrasse, Basel 4056, Switzerland
| | - Lukas C Kapitein
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584, the Netherlands
| | - Gijsje Koenderink
- Department of Living Matter, AMOLF, Science Park 104, Amsterdam 1098, the Netherlands
| | - Marileen Dogterom
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Van der Maasweg 9, Delft 2629, the Netherlands.
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, Utrecht 3584, the Netherlands.
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12
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Barbiero I, Peroni D, Siniscalchi P, Rusconi L, Tramarin M, De Rosa R, Motta P, Bianchi M, Kilstrup-Nielsen C. Pregnenolone and pregnenolone-methyl-ether rescue neuronal defects caused by dysfunctional CLIP170 in a neuronal model of CDKL5 Deficiency Disorder. Neuropharmacology 2020; 164:107897. [DOI: 10.1016/j.neuropharm.2019.107897] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 11/20/2019] [Accepted: 11/30/2019] [Indexed: 02/06/2023]
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13
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Qasim MZ, Hammad HM, Abbas F, Saeed S, Bakhat HF, Nasim W, Farhad W, Rabbani F, Fahad S. The potential applications of picotechnology in biomedical and environmental sciences. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:133-142. [PMID: 31832939 DOI: 10.1007/s11356-019-06554-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/16/2019] [Indexed: 06/10/2023]
Abstract
Picotechnology development in vast disciplines is mainly attributed to the research and development (R and D) on nanotechnology. Being a parent technology, nanotechnology is the cornerstone of picotechnology. Like nanotechnology, the reference standard for picotechnology is nature, the cellular and subcellular functioning. Some studies have highlighted that the functional margin of similar type of molecules at picoscale (10-12) goes higher than at nanoscale (10-9). In this review, the potential applications of picotechnology have been evaluated especially in the disciplines of biomedical and environmental sciences. Extended surface area and improved electrical, chemical, optical, and mechanical properties make picotechnological products even better than nanomaterials. The fundamental objective of this study is to bring the attention of the scientific world towards the picoscale interventions and to highlight the wide scope of picotechnology as a newly emerging technology with applications in numerous sectors. Picotechnology has made it possible to measure very small structure in advance biomedical and environmental sciences studies. Adequate developments in picotechnology will certainly change human lives in near future because it will make possible for the research world to dive into systems and structures on picoscale. It will render a platform through which explorers can travel into ultra-small areas, which will lead to the creation of new dimensions as well as new opportunities. Eventually, in future, the picotechnology will become smaller enough to give birth to femtotechnology (10-15) in real-world applications.
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Affiliation(s)
- Muhammad Zeeshan Qasim
- Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, 210094, People's Republic of China
| | - Hafiz Mohkum Hammad
- Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, Vehari, 61100, Pakistan.
| | - Farhat Abbas
- Faculty of Sustainable Design Engineering, University of Prince Edward Island, Charlottetown, PE, C1A 4P3, Canada
| | - Shafqat Saeed
- Department of Entomology, Muhammad Nawaz Shareef University of Agriculture, Multan, Pakistan
| | - Hafiz Faiq Bakhat
- Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, Vehari, 61100, Pakistan
| | - Wajid Nasim
- Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, Vehari, 61100, Pakistan
| | - Wajid Farhad
- University College of Dera Murad Jamali Naseerabad, Sub-Campus Lasbela University of Agriculture, Water and Marine Sciences, Uthal, 90150, Pakistan
| | - Faiz Rabbani
- Department of Environmental Sciences, COMSATS University Islamabad, Vehari Campus, Vehari, 61100, Pakistan
| | - Shah Fahad
- Department of Agriculture, The University of Swabi, Ambar, Khyber Pakhtunkhwa, Pakistan.
- College of Plant Science and Technology, Huazhong Agriculture University, Wuhan, China.
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14
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David AF, Roudot P, Legant WR, Betzig E, Danuser G, Gerlich DW. Augmin accumulation on long-lived microtubules drives amplification and kinetochore-directed growth. J Cell Biol 2019; 218:2150-2168. [PMID: 31113824 PMCID: PMC6605806 DOI: 10.1083/jcb.201805044] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 12/19/2018] [Accepted: 04/30/2019] [Indexed: 12/31/2022] Open
Abstract
Vertebrate cells assemble mitotic spindles through multiple pathways. It is shown that Augmin-dependent, noncentrosomal nucleation generates the vast majority of microtubules in metaphase spindles. This results in a strong directional bias of microtubule growth toward individual kinetochores. Dividing cells reorganize their microtubule cytoskeleton into a bipolar spindle, which moves one set of sister chromatids to each nascent daughter cell. Early spindle assembly models postulated that spindle pole–derived microtubules search the cytoplasmic space until they randomly encounter a kinetochore to form a stable attachment. More recent work uncovered several additional, centrosome-independent microtubule generation pathways, but the contributions of each pathway to spindle assembly have remained unclear. Here, we combined live microscopy and mathematical modeling to show that most microtubules nucleate at noncentrosomal regions in dividing human cells. Using a live-cell probe that selectively labels aged microtubule lattices, we demonstrate that the distribution of growing microtubule plus ends can be almost entirely explained by Augmin-dependent amplification of long-lived microtubule lattices. By ultrafast 3D lattice light-sheet microscopy, we observed that this mechanism results in a strong directional bias of microtubule growth toward individual kinetochores. Our systematic quantification of spindle dynamics reveals highly coordinated microtubule growth during kinetochore fiber assembly.
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Affiliation(s)
- Ana F David
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Philippe Roudot
- Department of Cell Biology and Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Wesley R Legant
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Eric Betzig
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Gaudenz Danuser
- Department of Cell Biology and Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
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15
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van Haren J, Wittmann T. Microtubule Plus End Dynamics - Do We Know How Microtubules Grow?: Cells boost microtubule growth by promoting distinct structural transitions at growing microtubule ends. Bioessays 2019; 41:e1800194. [PMID: 30730055 PMCID: PMC7021488 DOI: 10.1002/bies.201800194] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/22/2018] [Indexed: 12/31/2022]
Abstract
Microtubules form a highly dynamic filament network in all eukaryotic cells. Individual microtubules grow by tubulin dimer subunit addition and frequently switch between phases of growth and shortening. These unique dynamics are powered by GTP hydrolysis and drive microtubule network remodeling, which is central to eukaryotic cell biology and morphogenesis. Yet, our knowledge of the molecular events at growing microtubule ends remains incomplete. Here, recent ultrastructural, biochemical and cell biological data are integrated to develop a realistic model of growing microtubule ends comprised of structurally distinct but biochemically overlapping zones. Proteins that recognize microtubule lattice conformations associated with specific tubulin guanosine nucleotide states may independently control major structural transitions at growing microtubule ends. A model is proposed in which tubulin dimer addition and subsequent closure of the MT wall are optimized in cells to achieve rapid physiological microtubule growth.
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Affiliation(s)
- Jeffrey van Haren
- Department of Cell and Tissue Biology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA
| | - Torsten Wittmann
- Department of Cell and Tissue Biology, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA, 94143, USA
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16
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Rodriguez-Garcia R, Chesneau L, Pastezeur S, Roul J, Tramier M, Pécréaux J. The polarity-induced force imbalance in Caenorhabditis elegans embryos is caused by asymmetric binding rates of dynein to the cortex. Mol Biol Cell 2018; 29:3093-3104. [PMID: 30332325 PMCID: PMC6340208 DOI: 10.1091/mbc.e17-11-0653] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 10/04/2018] [Accepted: 10/10/2018] [Indexed: 12/17/2022] Open
Abstract
During asymmetric cell division, the molecular motor dynein generates cortical pulling forces that position the spindle to reflect polarity and adequately distribute cell fate determinants. In Caenorhabditis elegans embryos, despite a measured anteroposterior force imbalance, antibody staining failed to reveal dynein enrichment at the posterior cortex, suggesting a transient localization there. Dynein accumulates at the microtubule plus ends, in an EBP-2EB-dependent manner. This accumulation, although not transporting dynein, contributes modestly to cortical forces. Most dyneins may instead diffuse to the cortex. Tracking of cortical dynein revealed two motions: one directed and the other diffusive-like, corresponding to force-generating events. Surprisingly, while dynein is not polarized at the plus ends or in the cytoplasm, diffusive-like tracks were more frequently found at the embryo posterior tip, where the forces are higher. This asymmetry depends on GPR-1/2LGN and LIN-5NuMA, which are enriched there. In csnk-1(RNAi) embryos, the inverse distribution of these proteins coincides with an increased frequency of diffusive-like tracks anteriorly. Importantly, dynein cortical residence time is always symmetric. We propose that the dynein-binding rate at the posterior cortex is increased, causing the polarity-reflecting force imbalance. This mechanism of control supplements the regulation of mitotic progression through the nonpolarized dynein detachment rate.
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Affiliation(s)
- Ruddi Rodriguez-Garcia
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Laurent Chesneau
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Sylvain Pastezeur
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Julien Roul
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Marc Tramier
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
| | - Jacques Pécréaux
- CNRS, Univ Rennes, IGDR (Institute of Genetics and Development of Rennes)–UMR 6290, F-35000 Rennes, France
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17
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TAPping into the treasures of tubulin using novel protein production methods. Essays Biochem 2018; 62:781-792. [PMID: 30429282 PMCID: PMC6281476 DOI: 10.1042/ebc20180033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/03/2018] [Accepted: 10/22/2018] [Indexed: 01/02/2023]
Abstract
Microtubules are cytoskeletal elements with important cellular functions, whose dynamic behaviour and properties are in part regulated by microtubule-associated proteins (MAPs). The building block of microtubules is tubulin, a heterodimer of α- and β-tubulin subunits. Longitudinal interactions between tubulin dimers facilitate a head-to-tail arrangement of dimers into protofilaments, while lateral interactions allow the formation of a hollow microtubule tube that mostly contains 13 protofilaments. Highly homologous α- and β-tubulin isotypes exist, which are encoded by multi-gene families. In vitro studies on microtubules and MAPs have largely relied on brain-derived tubulin preparations. However, these consist of an unknown mix of tubulin isotypes with undefined post-translational modifications. This has blocked studies on the functions of tubulin isotypes and the effects of tubulin mutations found in human neurological disorders. Fortunately, various methodologies to produce recombinant mammalian tubulins have become available in the last years, allowing researchers to overcome this barrier. In addition, affinity-based purification of tagged tubulins and identification of tubulin-associated proteins (TAPs) by mass spectrometry has revealed the 'tubulome' of mammalian cells. Future experiments with recombinant tubulins should allow a detailed description of how tubulin isotype influences basic microtubule behaviour, and how MAPs and TAPs impinge on tubulin isotypes and microtubule-based processes in different cell types.
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18
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van Haren J, Charafeddine RA, Ettinger A, Wang H, Hahn KM, Wittmann T. Local control of intracellular microtubule dynamics by EB1 photodissociation. Nat Cell Biol 2018; 20:252-261. [PMID: 29379139 PMCID: PMC5826794 DOI: 10.1038/s41556-017-0028-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 12/13/2017] [Indexed: 12/18/2022]
Abstract
End-binding proteins, EBs, are adaptors that recruit functionally diverse +TIP proteins to growing microtubule plus ends. To test with high spatial and temporal accuracy how, when and where +TIP protein complexes contribute to dynamic cell biology, we developed a photo-inactivated EB1 variant (π-EB1) by inserting a blue light-sensitive protein-protein interaction module between the microtubule- and +TIP-binding domains of EB1. π-EB1 replaces endogenous EB1 function in the absence of blue light. In contrast, blue light-mediated π-EB1 photo-dissociation results in rapid +TIP complex disassembly, and acutely and reversibly attenuates microtubule growth independent of microtubule end association of the microtubule polymerase CKAP5 (ch-TOG, XMAP215). Local π-EB1 photo-dissociation allows subcellular microtubule dynamics control at the second and micrometre scale, and elicits aversive turning of migrating cancer cells. Importantly, light-mediated domain splitting can serve as template to optically control other intracellular protein activities.
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Affiliation(s)
- Jeffrey van Haren
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Rabab A Charafeddine
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Andreas Ettinger
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA.,Institute of Epigenetics and Stem Cells, Helmholtz Center Munich, München, Germany
| | - Hui Wang
- University of North Carolina, Chapel Hill, NC, USA
| | - Klaus M Hahn
- University of North Carolina, Chapel Hill, NC, USA
| | - Torsten Wittmann
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA.
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19
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Barbiero I, Peroni D, Tramarin M, Chandola C, Rusconi L, Landsberger N, Kilstrup-Nielsen C. The neurosteroid pregnenolone reverts microtubule derangement induced by the loss of a functional CDKL5-IQGAP1 complex. Hum Mol Genet 2018. [PMID: 28641386 DOI: 10.1093/hmg/ddx237] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
CDKL5 is a protein kinase that plays a key role for neuronal functions as testified by the onset of complex neuronal dysfunctions in patients with genetic lesions in CDKL5. Here we identify a novel interactor of CDKL5, IQGAP1, a fundamental regulator of cell migration and polarity. In accordance with a functional role of this interaction, depletion of CDKL5 impairs cell migration and impedes the localization of IQGAP1 at the leading edge. Moreover, we demonstrate that CDKL5 is required for IQGAP1 to form a functional complex with its effectors, Rac1 and the microtubule plus end tracking protein CLIP170. These defects eventually impact on the microtubule association of CLIP170, thus deranging their dynamics. CLIP170 is a cellular target of the neurosteroid pregnenolone; by blocking CLIP170 in its active conformation, pregnenolone is capable of restoring the microtubule association of CLIP170 in CDKL5 deficient cells and rescuing morphological defects in neurons devoid of CDKL5. These findings provide novel insights into CDKL5 functions and pave the way for target-specific therapeutic strategies for individuals affected with CDKL5-disorder.
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Affiliation(s)
- Isabella Barbiero
- Department of Biotechnology and Life Sciences and Center of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy
| | - Diana Peroni
- Department of Biotechnology and Life Sciences and Center of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy
| | - Marco Tramarin
- Department of Biotechnology and Life Sciences and Center of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy
| | - Chetan Chandola
- Department of Biotechnology and Life Sciences and Center of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy
| | - Laura Rusconi
- Department of Biotechnology and Life Sciences and Center of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy
| | - Nicoletta Landsberger
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy
| | - Charlotte Kilstrup-Nielsen
- Department of Biotechnology and Life Sciences and Center of Neuroscience, University of Insubria, 21052 Busto Arsizio, Italy
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20
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Jakka P, Bhargavi B, Namani S, Murugan S, Splitter G, Radhakrishnan G. Cytoplasmic Linker Protein CLIP170 Negatively Regulates TLR4 Signaling by Targeting the TLR Adaptor Protein TIRAP. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2018; 200:704-714. [PMID: 29222167 PMCID: PMC5760445 DOI: 10.4049/jimmunol.1601559] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 11/05/2017] [Indexed: 02/06/2023]
Abstract
Cytoplasmic linker protein 170 (CLIP170) is a CAP-Gly domain-containing protein that is associated with the plus end of growing microtubules and implicated in various cellular processes, including the regulation of microtubule dynamics, cell migration, and intracellular transport. Our studies revealed a previously unrecognized property and role of CLIP170. We identified CLIP170 as one of the interacting partners of Brucella effector protein TcpB that negatively regulates TLR2 and TLR4 signaling. In this study, we demonstrate that CLIP170 interacts with the TLR2 and TLR4 adaptor protein TIRAP. Furthermore, our studies revealed that CLIP170 induces ubiquitination and subsequent degradation of TIRAP to negatively regulate TLR4-mediated proinflammatory responses. Overexpression of CLIP170 in mouse macrophages suppressed the LPS-induced expression of IL-6 and TNF-α whereas silencing of endogenous CLIP170 potentiated the levels of proinflammatory cytokines. In vivo silencing of CLIP170 in C57BL/6 mice by CLIP170-specific small interfering RNA enhanced LPS-induced IL-6 and TNF-α expression. Furthermore, we found that LPS modulates the expression of CLIP170 in mouse macrophages. Overall, our experimental data suggest that CLIP170 serves as an intrinsic negative regulator of TLR4 signaling that targets TIRAP.
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Affiliation(s)
- Padmaja Jakka
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India
- Graduate Studies, Manipal University, Manipal, Karnataka 576104, India; and
| | - Bindu Bhargavi
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India
| | - Swapna Namani
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India
| | - Subathra Murugan
- National Institute of Animal Biotechnology, Hyderabad, Telangana 500049, India
| | - Gary Splitter
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI 53706
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21
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Vleugel M, Kok M, Dogterom M. Understanding force-generating microtubule systems through in vitro reconstitution. Cell Adh Migr 2017; 10:475-494. [PMID: 27715396 PMCID: PMC5079405 DOI: 10.1080/19336918.2016.1241923] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Microtubules switch between growing and shrinking states, a feature known as dynamic instability. The biochemical parameters underlying dynamic instability are modulated by a wide variety of microtubule-associated proteins that enable the strict control of microtubule dynamics in cells. The forces generated by controlled growth and shrinkage of microtubules drive a large range of processes, including organelle positioning, mitotic spindle assembly, and chromosome segregation. In the past decade, our understanding of microtubule dynamics and microtubule force generation has progressed significantly. Here, we review the microtubule-intrinsic process of dynamic instability, the effect of external factors on this process, and how the resulting forces act on various biological systems. Recently, reconstitution-based approaches have strongly benefited from extensive biochemical and biophysical characterization of individual components that are involved in regulating or transmitting microtubule-driven forces. We will focus on the current state of reconstituting increasingly complex biological systems and provide new directions for future developments.
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Affiliation(s)
- Mathijs Vleugel
- a Department of Bionanoscience , Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft Institute of Technology , Delft , The Netherlands
| | - Maurits Kok
- a Department of Bionanoscience , Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft Institute of Technology , Delft , The Netherlands
| | - Marileen Dogterom
- a Department of Bionanoscience , Kavli Institute of Nanoscience, Faculty of Applied Sciences, Delft Institute of Technology , Delft , The Netherlands
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22
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Nehlig A, Molina A, Rodrigues-Ferreira S, Honoré S, Nahmias C. Regulation of end-binding protein EB1 in the control of microtubule dynamics. Cell Mol Life Sci 2017; 74:2381-2393. [PMID: 28204846 PMCID: PMC11107513 DOI: 10.1007/s00018-017-2476-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/13/2017] [Accepted: 01/24/2017] [Indexed: 12/14/2022]
Abstract
The regulation of microtubule dynamics is critical to ensure essential cell functions, such as proper segregation of chromosomes during mitosis or cell polarity and migration. End-binding protein 1 (EB1) is a plus-end-tracking protein (+TIP) that accumulates at growing microtubule ends and plays a pivotal role in the regulation of microtubule dynamics. EB1 autonomously binds an extended tubulin-GTP/GDP-Pi structure at growing microtubule ends and acts as a molecular scaffold that recruits a large number of regulatory +TIPs through interaction with CAP-Gly or SxIP motifs. While extensive studies have focused on the structure of EB1-interacting site at microtubule ends and its role as a molecular platform, the mechanisms involved in the negative regulation of EB1 have only started to emerge and remain poorly understood. In this review, we summarize recent studies showing that EB1 association with MT ends is regulated by post-translational modifications and affected by microtubule-targeting agents. We also present recent findings that structural MAPs, that have no tip-tracking activity, physically interact with EB1 to prevent its accumulation at microtubule plus ends. These observations point out a novel concept of "endogenous EB1 antagonists" and emphasize the importance of finely regulating EB1 function at growing microtubule ends.
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Affiliation(s)
- Anne Nehlig
- Inserm U981, Institut Gustave Roussy, 114 rue Edouard Vaillant, 94800, Villejuif, France
- University Paris Saclay, 94800, Villejuif, France
| | - Angie Molina
- Inserm U981, Institut Gustave Roussy, 114 rue Edouard Vaillant, 94800, Villejuif, France
- University Paris Saclay, 94800, Villejuif, France
- CBD, University of Toulouse-3, Toulouse, France
| | - Sylvie Rodrigues-Ferreira
- Inserm U981, Institut Gustave Roussy, 114 rue Edouard Vaillant, 94800, Villejuif, France
- University Paris Saclay, 94800, Villejuif, France
| | - Stéphane Honoré
- Aix Marseille University, Inserm U-911, CRO2, Marseille, France
- Service Pharmacie, CHU Hôpital de La Timone, APHM, Marseille, France
| | - Clara Nahmias
- Inserm U981, Institut Gustave Roussy, 114 rue Edouard Vaillant, 94800, Villejuif, France.
- University Paris Saclay, 94800, Villejuif, France.
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23
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Fong KW, Au FKC, Jia Y, Yang S, Zhou L, Qi RZ. Microtubule plus-end tracking of end-binding protein 1 (EB1) is regulated by CDK5 regulatory subunit-associated protein 2. J Biol Chem 2017; 292:7675-7687. [PMID: 28320860 DOI: 10.1074/jbc.m116.759746] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 03/15/2017] [Indexed: 01/08/2023] Open
Abstract
Microtubules are polar cytoskeleton filaments that extend via growth at their plus ends. Microtubule plus-end-tracking proteins (+TIPs) accumulate at these growing plus ends to control microtubule dynamics and attachment. The +TIP end-binding protein 1 (EB1) and its homologs possess an autonomous plus-end-tracking mechanism and interact with other known +TIPs, which then recruit those +TIPs to the growing plus ends. A major +TIP class contains the SXIP (Ser-X-Ile-Pro, with X denoting any amino acid residue) motif, known to interact with EB1 and its homologs for plus-end tracking, but the role of SXIP in regulating EB1 activities is unclear. We show here that an interaction of EB1 with the SXIP-containing +TIP CDK5 regulatory subunit-associated protein 2 (CDK5RAP2) regulates several EB1 activities, including microtubule plus-end tracking, dynamics at microtubule plus ends, microtubule and α/β-tubulin binding, and microtubule polymerization. The SXIP motif fused with a dimerization domain from CDK5RAP2 significantly enhanced EB1 plus-end-tracking and microtubule-polymerizing and bundling activities, but the SXIP motif alone failed to do so. An SXIP-binding-deficient EB1 mutant displayed significantly lower microtubule plus-end tracking than the wild-type protein in transfected cells. These results suggest that EB1 cooperates with CDK5RAP2 and perhaps other SXIP-containing +TIPs in tracking growing microtubule tips. We also generated plus-end-tracking chimeras of CDK5RAP2 and the adenomatous polyposis coli protein (APC) and found that overexpression of the dimerization domains interfered with microtubule plus-end tracking of their respective SXIP-containing chimeras. Our results suggest that disruption of SXIP dimerization enables detailed investigations of microtubule plus-end-associated functions of individual SXIP-containing +TIPs.
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Affiliation(s)
- Ka-Wing Fong
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Franco K C Au
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Yue Jia
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Shaozhong Yang
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Liying Zhou
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Robert Z Qi
- From the Division of Life Science and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
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Velot L, Molina A, Rodrigues-Ferreira S, Nehlig A, Bouchet BP, Morel M, Leconte L, Serre L, Arnal I, Braguer D, Savina A, Honore S, Nahmias C. Negative regulation of EB1 turnover at microtubule plus ends by interaction with microtubule-associated protein ATIP3. Oncotarget 2016; 6:43557-70. [PMID: 26498358 PMCID: PMC4791250 DOI: 10.18632/oncotarget.6196] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 10/14/2015] [Indexed: 01/15/2023] Open
Abstract
The regulation of microtubule dynamics is critical to ensure essential cell functions. End binding protein 1 (EB1) is a master regulator of microtubule dynamics that autonomously binds an extended GTP/GDP-Pi structure at growing microtubule ends and recruits regulatory proteins at this location. However, negative regulation of EB1 association with growing microtubule ends remains poorly understood. We show here that microtubule-associated tumor suppressor ATIP3 interacts with EB1 through direct binding of a non-canonical proline-rich motif. Results indicate that ATIP3 does not localize at growing microtubule ends and that in situ ATIP3-EB1 molecular complexes are mostly detected in the cytosol. We present evidence that a minimal EB1-interacting sequence of ATIP3 is both necessary and sufficient to prevent EB1 accumulation at growing microtubule ends in living cells and that EB1-interaction is involved in reducing cell polarity. By fluorescence recovery of EB1-GFP after photobleaching, we show that ATIP3 silencing accelerates EB1 turnover at microtubule ends with no modification of EB1 diffusion in the cytosol. We propose a novel mechanism by which ATIP3-EB1 interaction indirectly reduces the kinetics of EB1 exchange on its recognition site, thereby accounting for negative regulation of microtubule dynamic instability. Our findings provide a unique example of decreased EB1 turnover at growing microtubule ends by cytosolic interaction with a tumor suppressor.
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Affiliation(s)
- Lauriane Velot
- Inserm U981, Institut Gustave Roussy Department of Molecular Medicine, Villejuif, France.,Université Paris-Saclay, Villejuif, France.,CNRS UMR8104, Institut Cochin, Paris, France
| | - Angie Molina
- Inserm U981, Institut Gustave Roussy Department of Molecular Medicine, Villejuif, France.,Université Paris-Saclay, Villejuif, France.,CNRS UMR8104, Institut Cochin, Paris, France
| | - Sylvie Rodrigues-Ferreira
- Inserm U981, Institut Gustave Roussy Department of Molecular Medicine, Villejuif, France.,Université Paris-Saclay, Villejuif, France.,CNRS UMR8104, Institut Cochin, Paris, France
| | - Anne Nehlig
- Inserm U981, Institut Gustave Roussy Department of Molecular Medicine, Villejuif, France.,Université Paris-Saclay, Villejuif, France
| | - Benjamin Pierre Bouchet
- Cell Biology, Faculty of Science, Utrecht University, Padualaan, CH Utrecht, The Netherlands
| | | | - Ludovic Leconte
- Cell and Tissue Imaging Core Facilty, PICT-IBiSA, CNRS UMR144 Institut Curie, Centre de Recherche, Paris, France
| | - Laurence Serre
- Inserm U836, Grenoble Institut des Neurosciences, Grenoble, France
| | - Isabelle Arnal
- Inserm U836, Grenoble Institut des Neurosciences, Grenoble, France
| | - Diane Braguer
- Aix Marseille Université, Inserm, CRO2 UMR_S 911, Marseille, France.,APHM, Hôpital Timone, Marseille, France
| | - Ariel Savina
- Scientific Partnerships Roche SAS, Boulogne Billancourt, France
| | - Stéphane Honore
- Aix Marseille Université, Inserm, CRO2 UMR_S 911, Marseille, France.,APHM, Hôpital Timone, Marseille, France
| | - Clara Nahmias
- Inserm U981, Institut Gustave Roussy Department of Molecular Medicine, Villejuif, France.,Université Paris-Saclay, Villejuif, France.,CNRS UMR8104, Institut Cochin, Paris, France
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25
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Courtheoux T, Enchev RI, Lampert F, Gerez J, Beck J, Picotti P, Sumara I, Peter M. Cortical dynamics during cell motility are regulated by CRL3(KLHL21) E3 ubiquitin ligase. Nat Commun 2016; 7:12810. [PMID: 27641145 PMCID: PMC5031805 DOI: 10.1038/ncomms12810] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 08/01/2016] [Indexed: 12/18/2022] Open
Abstract
Directed cell movement involves spatial and temporal regulation of the cortical microtubule (Mt) and actin networks to allow focal adhesions (FAs) to assemble at the cell front and disassemble at the rear. Mts are known to associate with FAs, but the mechanisms coordinating their dynamic interactions remain unknown. Here we show that the CRL3KLHL21 E3 ubiquitin ligase promotes cell migration by controlling Mt and FA dynamics at the cell cortex. Indeed, KLHL21 localizes to FA structures preferentially at the leading edge, and in complex with Cul3, ubiquitylates EB1 within its microtubule-interacting CH-domain. Cells lacking CRL3KLHL21 activity or expressing a non-ubiquitylatable EB1 mutant protein are unable to migrate and exhibit strong defects in FA dynamics, lamellipodia formation and cortical plasticity. Our study thus reveals an important mechanism to regulate cortical dynamics during cell migration that involves ubiquitylation of EB1 at focal adhesions. Although focal adhesions (FAs) and microtubules (MTs) are known to associate, the underlying regulation of this dynamic interaction is not understood. Here the authors discover that the CRL3KLHL21 E3 ubiquitin ligase localises to FAs and ubiquitinates the MT plus-tip binding protein EB1, thereby promoting MT and FA dynamics and cell migration.
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Affiliation(s)
- Thibault Courtheoux
- Institute of Biochemistry, Department of Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Radoslav I Enchev
- Institute of Biochemistry, Department of Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Fabienne Lampert
- Institute of Biochemistry, Department of Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Juan Gerez
- Institute of Biochemistry, Department of Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Jochen Beck
- Institute of Biochemistry, Department of Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Paola Picotti
- Institute of Biochemistry, Department of Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
| | - Izabela Sumara
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique UMR 7104, Institut National de la Santé et de la Recherche Médicale U964, Université de Strasbourg, 67404 Illkirch, France
| | - Matthias Peter
- Institute of Biochemistry, Department of Biology, ETH Zurich, Otto-Stern-Weg 3, 8093 Zürich, Switzerland
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26
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Insights into the process of EB1-dependent tip-tracking of kinesin-14 Ncd. The role of the microtubule. Eur J Cell Biol 2016; 95:521-530. [PMID: 27608966 DOI: 10.1016/j.ejcb.2016.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 08/11/2016] [Accepted: 08/29/2016] [Indexed: 01/13/2023] Open
Abstract
End-binding proteins are capable of tracking the plus-ends of growing microtubules (MTs). The motor protein Ncd, a member of the kinesin-14 family, interacts with EB1 protein and becomes a non-autonomous tip-tracker. Here, we attempted to find out whether at least for Ncd, the efficient EB1-mediated tip-tracking involves the interaction of the kinesin with the MT surface. We prepared a series of Ncd tail mutants in which the MT-binding sites were altered or eliminated. Using TIRF microscopy, we characterized their behavior as tip-trackers and measured the dwell times of single molecules of EB1 and Ncd tail or its mutated forms. The mutated forms of Ncd tail exhibited tip-tracking in the presence of EB1 and the effectiveness of this process was proportional to the affinity of the mutant's tail to MT. Even though the interaction of Ncd with EB1 was weak (Kd∼9μM) the half saturating concentration of EB1 for tip-tracking was 7nM. The dwell time of Ncd tail in the presence of EB1 was ∼1s. The dwell time of EB1 alone was shorter (∼0.3s) and increased considerably in the presence of a large excess of Ncd tail. We demonstrated that tip-tracking of kinesin-14 occurs through several concurrent mechanisms: binding of kinesin only to EB1 located at the MT end, interaction of the kinesin molecules with a composite site formed by EB1 and the MT tip, and probably surface diffusion of the tail along MT. The second mechanism seems to play a crucial role in efficient tip-tracking.
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27
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Abstract
The growth and migration of neurons require continuous remodelling of the neuronal cytoskeleton, providing a versatile cellular framework for force generation and guided movement, in addition to structural support. Actin filaments and microtubules are central to the dynamic action of the cytoskeleton and rapid advances in imaging technologies are enabling ever more detailed visualisation of the dynamic intracellular networks that they form. However, these filaments do not act individually and an expanding body of evidence emphasises the importance of actin-microtubule crosstalk in orchestrating cytoskeletal dynamics. Here, we summarise our current understanding of the structure and dynamics of actin and microtubules in isolation, before reviewing both the mechanisms and the molecular players involved in mediating actin-microtubule crosstalk in neurons.
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Affiliation(s)
- Charlotte H Coles
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
| | - Frank Bradke
- Laboratory for Axon Growth and Regeneration, German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175, Bonn, Germany.
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28
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van de Willige D, Hoogenraad CC, Akhmanova A. Microtubule plus-end tracking proteins in neuronal development. Cell Mol Life Sci 2016; 73:2053-77. [PMID: 26969328 PMCID: PMC4834103 DOI: 10.1007/s00018-016-2168-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 02/04/2016] [Accepted: 02/22/2016] [Indexed: 11/28/2022]
Abstract
Regulation of the microtubule cytoskeleton is of pivotal importance for neuronal development and function. One such regulatory mechanism centers on microtubule plus-end tracking proteins (+TIPs): structurally and functionally diverse regulatory factors, which can form complex macromolecular assemblies at the growing microtubule plus-ends. +TIPs modulate important properties of microtubules including their dynamics and their ability to control cell polarity, membrane transport and signaling. Several neurodevelopmental and neurodegenerative diseases are associated with mutations in +TIPs or with misregulation of these proteins. In this review, we focus on the role and regulation of +TIPs in neuronal development and associated disorders.
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Affiliation(s)
- Dieudonnée van de Willige
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
| | - Anna Akhmanova
- Cell Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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29
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Menon S, Gupton SL. Building Blocks of Functioning Brain: Cytoskeletal Dynamics in Neuronal Development. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 322:183-245. [PMID: 26940519 PMCID: PMC4809367 DOI: 10.1016/bs.ircmb.2015.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neural connectivity requires proper polarization of neurons, guidance to appropriate target locations, and establishment of synaptic connections. From when neurons are born to when they finally reach their synaptic partners, neurons undergo constant rearrangment of the cytoskeleton to achieve appropriate shape and polarity. Of particular importance to neuronal guidance to target locations is the growth cone at the tip of the axon. Growth-cone steering is also dictated by the underlying cytoskeleton. All these changes require spatiotemporal control of the cytoskeletal machinery. This review summarizes the proteins that are involved in modulating the actin and microtubule cytoskeleton during the various stages of neuronal development.
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Affiliation(s)
- Shalini Menon
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, United States of America
| | - Stephanie L Gupton
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, United States of America; Neuroscience Center and Curriculum in Neurobiology, University of North Carolina, Chapel Hill, NC, United States of America; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, United States of America.
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30
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Control of microtubule organization and dynamics: two ends in the limelight. Nat Rev Mol Cell Biol 2015; 16:711-26. [PMID: 26562752 DOI: 10.1038/nrm4084] [Citation(s) in RCA: 589] [Impact Index Per Article: 65.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Microtubules have fundamental roles in many essential biological processes, including cell division and intracellular transport. They assemble and disassemble from their two ends, denoted the plus end and the minus end. Significant advances have been made in our understanding of microtubule plus-end-tracking proteins (+TIPs) such as end-binding protein 1 (EB1), XMAP215, selected kinesins and dynein. By contrast, information on microtubule minus-end-targeting proteins (-TIPs), such as the calmodulin-regulated spectrin-associated proteins (CAMSAPs) and Patronin, has only recently started to emerge. Here, we review our current knowledge of factors, including microtubule-targeting agents, that associate with microtubule ends to control the dynamics and function of microtubules during the cell cycle and development.
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31
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Callejas-Negrete OA, Plamann M, Schnittker R, Bartnicki-García S, Roberson RW, Pimienta G, Mouriño-Pérez RR. Two microtubule-plus-end binding proteins LIS1-1 and LIS1-2, homologues of human LIS1 in Neurospora crassa. Fungal Genet Biol 2015; 82:213-27. [PMID: 26231681 DOI: 10.1016/j.fgb.2015.07.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/26/2015] [Accepted: 07/27/2015] [Indexed: 11/17/2022]
Abstract
LIS1 is a microtubule (Mt) plus-end binding protein that interacts with the dynein/dynactin complex. In humans, LIS1 is required for proper nuclear and organelle migration during cell growth. Although gene duplication is absent from Neurospora crassa, we found two paralogues of human LIS1. We named them LIS1-1 and LIS1-2 and studied their dynamics and function by fluorescent tagging. At the protein level, LIS1-1 and LIS1-2 were very similar. Although, the characteristic coiled-coil motif was not present in LIS1-2. LIS1-1-GFP and LIS1-2-GFP showed the same cellular distribution and dynamics, but LIS1-2-GFP was less abundant. Both LIS1 proteins were found in the subapical region as single fluorescent particles traveling toward the cell apex, they accumulated in the apical dome forming prominent short filament-like structures, some of which traversed the Spitzenkörper (Spk). The fluorescent structures moved exclusively in anterograde fashion along straight paths suggesting they traveled on Mts. There was no effect in the filament behavior of LIS1-1-GFP in the Δlis1-2 mutant but the dynamics of LIS1-2-GFP was affected in the Δlis1-1 mutant. Microtubular integrity and the dynein-dynactin complex were necessary for the formation of filament-like structures of LIS1-1-GFP in the subapical and apical regions; however, conventional kinesin (KIN-1) was not. Deletion mutants showed that the lack of lis1-1 decreased cell growth by ∼75%; however, the lack of lis1-2 had no effect on growth. A Δlis1-1;Δlis1-2 double mutant showed slower growth than either single mutant. Conidia production was reduced but branching rate increased in Δlis1-1 and the Δlis1-1;Δlis1-2 double mutants. The absence of LIS1-1 had a strong effect on Mt organization and dynamics and indirectly affected nuclear and mitochondrial distribution. The absence of LIS1-1 filaments in dynein mutants (ropy mutants) or in benomyl treated hyphae indicates the strong association between this protein and the regulation of the dynein-dynactin complex and Mt organization. LIS1-1 and LIS1-2 had a high amino acid homology, nevertheless, the absence of the coiled-coil motif in LIS1-2 suggests that its function or regulation may be distinct from that of LIS1-1.
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Affiliation(s)
- Olga A Callejas-Negrete
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico
| | - Michael Plamann
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Robert Schnittker
- School of Biological Sciences, University of Missouri-Kansas City, Kansas City, MO, USA
| | - Salomon Bartnicki-García
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico
| | | | - Genaro Pimienta
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico
| | - Rosa R Mouriño-Pérez
- Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada, B.C., Mexico.
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32
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Krishan S, Richardson DR, Sahni S. Adenosine Monophosphate–Activated Kinase and Its Key Role in Catabolism: Structure, Regulation, Biological Activity, and Pharmacological Activation. Mol Pharmacol 2014; 87:363-77. [DOI: 10.1124/mol.114.095810] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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33
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Galva C, Kirik V, Lindeboom JJ, Kaloriti D, Rancour DM, Hussey PJ, Bednarek SY, Ehrhardt DW, Sedbrook JC. The microtubule plus-end tracking proteins SPR1 and EB1b interact to maintain polar cell elongation and directional organ growth in Arabidopsis. THE PLANT CELL 2014; 26:4409-25. [PMID: 25415978 PMCID: PMC4277225 DOI: 10.1105/tpc.114.131482] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The microtubule plus-end tracking proteins (+TIPs) END BINDING1b (EB1b) and SPIRAL1 (SPR1) are required for normal cell expansion and organ growth. EB proteins are viewed as central regulators of +TIPs and cell polarity in animals; SPR1 homologs are specific to plants. To explore if EB1b and SPR1 fundamentally function together, we combined genetic, biochemical, and cell imaging approaches in Arabidopsis thaliana. We found that eb1b-2 spr1-6 double mutant roots exhibit substantially more severe polar expansion defects than either single mutant, undergoing right-looping growth and severe axial twisting instead of waving on tilted hard-agar surfaces. Protein interaction assays revealed that EB1b and SPR1 bind each other and tubulin heterodimers, which is suggestive of a microtubule loading mechanism. EB1b and SPR1 show antagonistic association with microtubules in vitro. Surprisingly, our combined analyses revealed that SPR1 can load onto microtubules and function independently of EB1 proteins, setting SPR1 apart from most studied +TIPs in animals and fungi. Moreover, we found that the severity of defects in microtubule dynamics in spr1 eb1b mutant hypocotyl cells correlated well with the severity of growth defects. These data indicate that SPR1 and EB1b have complex interactions as they load onto microtubule plus ends and direct polar cell expansion and organ growth in response to directional cues.
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Affiliation(s)
- Charitha Galva
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790
| | - Viktor Kirik
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790
| | | | - Despoina Kaloriti
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790
| | - David M Rancour
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706
| | - Patrick J Hussey
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, United Kingdom
| | | | | | - John C Sedbrook
- School of Biological Sciences, Illinois State University, Normal, Illinois 61790
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34
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Tanenbaum ME, Medema RH, Akhmanova A. Regulation of localization and activity of the microtubule depolymerase MCAK. BIOARCHITECTURE 2014; 1:80-87. [PMID: 21866268 DOI: 10.4161/bioa.1.2.15807] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 04/09/2011] [Indexed: 12/29/2022]
Abstract
Mitotic Centromere Associated Kinesin (MCAK) is a potent microtubule depolymerizing and catastrophe-inducing factor, which uses the energy of ATP hydrolysis to destabilize microtubule ends. MCAK is localized to inner centromeres, kinetochores and spindle poles of mitotic cells, and is also present in the cytoplasm. Both in interphase and in mitosis, MCAK can specifically accumulate at the growing microtubule ends. Here we discuss the mechanisms, which modulate subcellular localization and activity of MCAK through the interaction with the End Binding (EB) proteins and phosphorylation.
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Affiliation(s)
- Marvin E Tanenbaum
- Department of Medical Oncology and Cancer Genomics Center; University Medical Center; Utrecht, The Netherlands
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35
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Ferreira JG, Pereira AL, Maiato H. Microtubule plus-end tracking proteins and their roles in cell division. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 309:59-140. [PMID: 24529722 DOI: 10.1016/b978-0-12-800255-1.00002-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Microtubules are cellular components that are required for a variety of essential processes such as cell motility, mitosis, and intracellular transport. This is possible because of the inherent dynamic properties of microtubules. Many of these properties are tightly regulated by a number of microtubule plus-end-binding proteins or +TIPs. These proteins recognize the distal end of microtubules and are thus in the right context to control microtubule dynamics. In this review, we address how microtubule dynamics are regulated by different +TIP families, focusing on how functionally diverse +TIPs spatially and temporally regulate microtubule dynamics during animal cell division.
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Affiliation(s)
- Jorge G Ferreira
- Chromosome Instability & Dynamics Laboratory, Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal; Cell Division Unit, Department of Experimental Biology, University of Porto, Porto, Portugal
| | - Ana L Pereira
- Chromosome Instability & Dynamics Laboratory, Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal
| | - Helder Maiato
- Chromosome Instability & Dynamics Laboratory, Instituto de Biologia Molecular e Celular, University of Porto, Porto, Portugal; Cell Division Unit, Department of Experimental Biology, University of Porto, Porto, Portugal.
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36
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Gupta KK, Alberico EO, Näthke IS, Goodson HV. Promoting microtubule assembly: A hypothesis for the functional significance of the +TIP network. Bioessays 2014; 36:818-26. [PMID: 24943963 DOI: 10.1002/bies.201400029] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Regulation of microtubule (MT) dynamics is essential for many cellular processes, but the machinery that controls MT dynamics remains poorly understood. MT plus-end tracking proteins (+TIPs) are a set of MT-associated proteins that dynamically track growing MT ends and are uniquely positioned to govern MT dynamics. +TIPs associate with each other in a complex array of inter- and intra-molecular interactions known as the "+TIP network." Why do so many +TIPs bind to other +TIPs? Typical answers include the ideas that these interactions localize proteins where they are needed, deliver proteins to the cortex, and/or create regulatory pathways. We propose an additional and more mechanistic hypothesis: that +TIPs bind each other to create a superstructure that promotes MT assembly by constraining the structural fluctuations of the MT tip, thus acting as a polymerization chaperone.
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Affiliation(s)
- Kamlesh K Gupta
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, USA
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37
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Abstract
The PRKAA1 gene encodes the catalytic α-subunit of 5′ AMP-activated protein kinase (AMPK). AMPK is a cellular energy sensor that maintains energy homeostasis within the cell and is activated when the AMP/ATP ratio increases. When activated, AMPK increases catabolic processes that increase ATP synthesis and inhibit anabolic processes that require ATP. Additionally, AMPK also plays a role in activating autophagy and inhibiting energy consuming processes, such as cellular growth and proliferation. Due to its role in energy metabolism, it could act as a potential target of many therapeutic drugs that could be useful in the treatment of several diseases, for example, diabetes. Moreover, AMPK has been shown to be involved in inhibiting tumour growth and metastasis, and has also been implicated in the pathology of neurodegenerative and cardiac disorders. Hence, a better understanding of AMPK and its role in various pathological conditions could enable the development of strategies to use it as a therapeutic target.
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38
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End-binding protein 1 stimulates paclitaxel sensitivity in breast cancer by promoting its actions toward microtubule assembly and stability. Protein Cell 2014; 5:469-79. [PMID: 24748116 PMCID: PMC4026418 DOI: 10.1007/s13238-014-0053-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 03/09/2014] [Indexed: 12/21/2022] Open
Abstract
Paclitaxel is a microtubule-targeting agent widely used for the treatment of many solid tumors. However, patients show variable sensitivity to this drug, and effective diagnostic tests predicting drug sensitivity remain to be investigated. Herein, we show that the expression of end-binding protein 1 (EB1), a regulator of microtubule dynamics involved in multiple cellular activities, in breast tumor tissues correlates with the pathological response of tumors to paclitaxel-based chemotherapy. In vitro cell proliferation assays reveal that EB1 stimulates paclitaxel sensitivity in breast cancer cell lines. Our data further demonstrate that EB1 increases the activity of paclitaxel to cause mitotic arrest and apoptosis in cancer cells. In addition, microtubule binding affinity analysis and polymerization/depolymerization assays show that EB1 enhances paclitaxel binding to microtubules and stimulates the ability of paclitaxel to promote microtubule assembly and stabilization. These findings thus reveal EB1 as a critical regulator of paclitaxel sensitivity and have important implications in breast cancer chemotherapy.
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39
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Microtubule Minus-End Stabilization by Polymerization-Driven CAMSAP Deposition. Dev Cell 2014; 28:295-309. [DOI: 10.1016/j.devcel.2014.01.001] [Citation(s) in RCA: 205] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/17/2013] [Accepted: 01/02/2014] [Indexed: 11/22/2022]
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40
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Li D, Sun X, Zhang L, Yan B, Xie S, Liu R, Liu M, Zhou J. Histone deacetylase 6 and cytoplasmic linker protein 170 function together to regulate the motility of pancreatic cancer cells. Protein Cell 2014; 5:214-23. [PMID: 24474193 PMCID: PMC3967059 DOI: 10.1007/s13238-013-0010-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 11/05/2013] [Indexed: 01/01/2023] Open
Abstract
Pancreatic cancer is a devastating disease with the worst prognosis among all the major human malignancies. The propensity to rapidly metastasize contributes significantly to the highly aggressive feature of pancreatic cancer. The molecular mechanisms underlying this remain elusive, and proteins involved in the control of pancreatic cancer cell motility are not fully characterized. In this study, we find that histone deacetylase 6 (HDAC6), a member of the class II HDAC family, is highly expressed at both protein and mRNA levels in human pancreatic cancer tissues. HDAC6 does not obviously affect pancreatic cancer cell proliferation or cell cycle progression. Instead, it significantly promotes the motility of pancreatic cancer cells. Further studies reveal that HDAC6 interacts with cytoplasmic linker protein 170 (CLIP-170) and that these two proteins function together to stimulate the migration of pancreatic cancer cells. These findings provide mechanistic insight into the progression of pancreatic cancer and suggest HDAC6 as a potential target for the management of this malignancy.
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Affiliation(s)
- Dengwen Li
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
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41
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Mechanical and geometrical constraints control kinesin-based microtubule guidance. Curr Biol 2014; 24:322-8. [PMID: 24462000 DOI: 10.1016/j.cub.2014.01.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/22/2013] [Accepted: 01/03/2014] [Indexed: 01/07/2023]
Abstract
Proper organization of microtubule networks depends on microtubule-associated proteins and motors that use different spatial cues to guide microtubule growth [1-3]. For example, it has been proposed that the uniform minus-end-out microtubule organization in dendrites of Drosophila neurons is maintained by steering of polymerizing microtubules along the stable ones by kinesin-2 motors bound to growing microtubule plus ends [4]. To explore the mechanics of kinesin-guided microtubule growth, we reconstituted this process in vitro. In the presence of microtubule plus-end tracking EB proteins, a constitutively active kinesin linked to the EB-interacting motif SxIP effectively guided polymerizing microtubules along other microtubules both in cells and in vitro. Experiments combined with modeling revealed that at angles larger than 90°, guidance efficiency is determined by the force needed for microtubule bending. At angles smaller than 90°, guidance requires microtubule growth, and guidance efficiency depends on the ability of kinesins to maintain contact between the two microtubules despite the geometrical constraints imposed by microtubule length and growth rate. Our findings provide a conceptual framework for understanding microtubule guidance during the generation of different types of microtubule arrays.
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42
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Kakeno M, Matsuzawa K, Matsui T, Akita H, Sugiyama I, Ishidate F, Nakano A, Takashima S, Goto H, Inagaki M, Kaibuchi K, Watanabe T. Plk1 phosphorylates CLIP-170 and regulates its binding to microtubules for chromosome alignment. Cell Struct Funct 2014; 39:45-59. [PMID: 24451569 DOI: 10.1247/csf.14001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023] Open
Abstract
The microtubule (MT) cytoskeleton is essential for cellular morphogenesis, cell migration, and cell division. MT organization is primarily mediated by a variety of MT-associated proteins. Among these proteins, plus-end-tracking proteins (+TIPs) are evolutionarily conserved factors that selectively accumulate at growing MT plus ends. Cytoplasmic linker protein (CLIP)-170 is a +TIP that associates with diverse proteins to determine the behavior of MT ends and their linkage to intracellular structures, including mitotic chromosomes. However, how CLIP-170 activity is spatially and temporally controlled is largely unknown. Here, we show that phosphorylation at Ser312 in the third serine-rich region of CLIP-170 is increased during mitosis. Polo-like kinase 1 (Plk1) is responsible for this phosphorylation during the mitotic phase of dividing cells. In vitro analysis using a purified CLIP-170 N-terminal fragment showed that phosphorylation by Plk1 diminishes CLIP-170 binding to the MT ends and lattice without affecting binding to EB3. Furthermore, we demonstrate that during mitosis, stable kinetochore/MT attachment and subsequent chromosome alignment require CLIP-170 and a proper phosphorylation/dephosphorylation cycle at Ser312. We propose that CLIP-170 phosphorylation by Plk1 regulates proper chromosome alignment by modulating the interaction between CLIP-170 and MTs in mitotic cells and that CLIP-170 activity is stringently controlled by its phosphorylation state, which depends on the cellular context.
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Affiliation(s)
- Mai Kakeno
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine
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43
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Sayas CL, Avila J. Regulation of EB1/3 proteins by classical MAPs in neurons. BIOARCHITECTURE 2014; 4:1-5. [PMID: 24452057 DOI: 10.4161/bioa.27774] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Microtubules (MTs) are key cytoskeletal elements in developing and mature neurons. MT reorganization underlies the morphological changes that occur during neuronal development. Furthermore, MTs contribute to the maintenance of neuronal architecture, enable intracellular transport and act as scaffolds for signaling molecules. Thus, a fine-tuned regulation of MT dynamics and stability is crucial for the correct differentiation and functioning of neurons. Different types of proteins contribute to the regulation of the MT state, such as plus-end tracking proteins (+TIPs), which interact with the plus-ends of growing microtubules, and classical microtubule-associated proteins (MAPs), which bind along the microtubule lattice. Recent evidence indicates that MAPs interplay with End Binding Proteins (EBs), the core +TIPs, in neuronal cells. This might contribute to the orchestrated regulation of MT dynamics in neurons. In this mini-review article, we address recent research on the neuronal crosstalk between EBs and classical MAPs and speculate on its possible functional relevance.
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Affiliation(s)
- C L Sayas
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM); Universidad Autónoma de Madrid; Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED); Madrid, Spain
| | - Jesús Avila
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM); Universidad Autónoma de Madrid; Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED); Madrid, Spain
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44
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Dent EW, Baas PW. Microtubules in neurons as information carriers. J Neurochem 2013; 129:235-9. [PMID: 24266899 DOI: 10.1111/jnc.12621] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Revised: 10/23/2013] [Accepted: 11/20/2013] [Indexed: 11/28/2022]
Abstract
Microtubules in neurons consist of highly dynamic regions as well as stable regions, some of which persist after bouts of severing as short mobile polymers. Concentrated at the plus ends of the highly dynamic regions are microtubule plus end tracking proteins called +TIPs that can interact with an array of other proteins and structures relevant to the plasticity of the neuron. It is also provocative to ponder that short mobile microtubules might similarly convey information with them as they transit within the neuron. Thus, beyond their known conventional functions in supporting neuronal architecture and organelle transport, microtubules may act as 'information carriers' in the neuron.
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Affiliation(s)
- Erik W Dent
- Department of Neuroscience, University of Wisconsin, School of Medicine and Public Health, 1300 University Avenue, Madison, WI, USA
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45
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Li D, Sun X, Zhang L, Yan B, Xie S, Liu R, Liu M, Zhou J. Histone deacetylase 6 and cytoplasmic linker protein 170 function together to regulate the motility of pancreatic cancer cells. Protein Cell 2013. [PMID: 24264142 DOI: 10.1007/s13238-013-3098-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 11/06/2013] [Indexed: 11/24/2022] Open
Abstract
Pancreatic cancer is a devastating disease with the worst prognosis among all the major human malignancies. The propensity to rapidly metastasize contributes significantly to the highly aggressive feature of pancreatic cancer. The molecular mechanisms underlying this remain elusive, and proteins involved in the control of pancreatic cancer cell motility are not fully characterized. In this study, we find that histone deacetylase 6 (HDAC6), a member of the class II HDAC family, is highly expressed at both protein and mRNA levels in human pancreatic cancer tissues. HDAC6 does not obviously affect pancreatic cancer cell proliferation or cell cycle progression. Instead, it significantly promotes the motility of pancreatic cancer cells. Further studies reveal that HDAC6 interacts with cytoplasmic linker protein 170 (CLIP-170) and that these two proteins function together to stimulate the migration of pancreatic cancer cells. These findings provide mechanistic insight into the progression of pancreatic cancer and suggest HDAC6 as a potential target for the management of this malignancy.
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Affiliation(s)
- Dengwen Li
- Department of Genetics and Cell Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
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46
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Dinant C, Ampatziadis-Michailidis G, Lans H, Tresini M, Lagarou A, Grosbart M, Theil AF, van Cappellen WA, Kimura H, Bartek J, Fousteri M, Houtsmuller AB, Vermeulen W, Marteijn JA. Enhanced chromatin dynamics by FACT promotes transcriptional restart after UV-induced DNA damage. Mol Cell 2013; 51:469-79. [PMID: 23973375 DOI: 10.1016/j.molcel.2013.08.007] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 06/07/2013] [Accepted: 07/17/2013] [Indexed: 02/05/2023]
Abstract
Chromatin remodeling is tightly linked to all DNA-transacting activities. To study chromatin remodeling during DNA repair, we established quantitative fluorescence imaging methods to measure the exchange of histones in chromatin in living cells. We show that particularly H2A and H2B are evicted and replaced at an accelerated pace at sites of UV-induced DNA damage. This accelerated exchange of H2A/H2B is facilitated by SPT16, one of the two subunits of the histone chaperone FACT (facilitates chromatin transcription) but largely independent of its partner SSRP1. Interestingly, SPT16 is targeted to sites of UV light-induced DNA damage-arrested transcription and is required for efficient restart of RNA synthesis upon damage removal. Together, our data uncover an important role for chromatin dynamics at the crossroads of transcription and the UV-induced DNA damage response.
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Affiliation(s)
- Christoffel Dinant
- Department of Genetics, Erasmus Medical Centre, Rotterdam 3015 GE, The Netherlands
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47
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Weng JH, Liang MR, Chen CH, Tong SK, Huang TC, Lee SP, Chen YR, Chen CT, Chung BC. Pregnenolone activates CLIP-170 to promote microtubule growth and cell migration. Nat Chem Biol 2013; 9:636-42. [PMID: 23955365 DOI: 10.1038/nchembio.1321] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 07/24/2013] [Indexed: 01/09/2023]
Abstract
Pregnenolone (P5) is a neurosteroid that improves memory and neurological recovery. It is also required for zebrafish embryonic development. However, its mode of action is unclear. Here we show that P5 promotes cell migration and microtubule polymerization by binding a microtubule plus end-tracking protein, cytoplasmic linker protein 1 (CLIP-170). We captured CLIP-170 from zebrafish embryonic extract using a P5 photoaffinity probe conjugated to diaminobenzophenone. P5 interacted with CLIP-170 at its coiled-coil domain and changed it into an extended conformation. This increased CLIP-170 interaction with microtubules, dynactin subunit p150(Glued) and LIS1; it also promoted CLIP-170-dependent microtubule polymerization. CLIP-170 was essential for P5 to promote microtubule abundance and zebrafish epiboly cell migration during embryogenesis, and overexpression of the P5-binding region of CLIP-170 delayed this migration. P5 also sustained migration directionality of cultured mammalian cells. Our results show that P5 activates CLIP-170 to promote microtubule polymerization and cell migration.
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Affiliation(s)
- Jui-Hsia Weng
- 1] Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan. [2] Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
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48
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Bulgakova NA, Grigoriev I, Yap AS, Akhmanova A, Brown NH. Dynamic microtubules produce an asymmetric E-cadherin-Bazooka complex to maintain segment boundaries. ACTA ACUST UNITED AC 2013; 201:887-901. [PMID: 23751496 PMCID: PMC3678168 DOI: 10.1083/jcb.201211159] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Distributing junctional components around the cell periphery is key for epithelial tissue morphogenesis and homeostasis. We discovered that positioning of dynamic microtubules controls the asymmetric accumulation of E-cadherin. Microtubules are oriented preferentially along the dorso-ventral axis in Drosophila melanogaster embryonic epidermal cells, and thus more frequently contact E-cadherin at dorso-ventral cell-cell borders. This inhibits RhoGEF2, reducing membrane recruitment of Rho-kinase, and increasing a specific E-cadherin pool that is mobile when assayed by fluorescence recovery after photobleaching. This mobile E-cadherin is complexed with Bazooka/Par-3, which in turn is required for normal levels of mobile E-cadherin. Mobile E-cadherin-Bazooka prevents formation of multicellular rosette structures and cell motility across the segment border in Drosophila embryos. Altogether, the combined action of dynamic microtubules and Rho signaling determines the level and asymmetric distribution of a mobile E-cadherin-Bazooka complex, which regulates cell behavior during the generation of a patterned epithelium.
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Affiliation(s)
- Natalia A Bulgakova
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, England, UK
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49
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MAP1B regulates microtubule dynamics by sequestering EB1/3 in the cytosol of developing neuronal cells. EMBO J 2013; 32:1293-306. [PMID: 23572079 DOI: 10.1038/emboj.2013.76] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 03/08/2013] [Indexed: 01/17/2023] Open
Abstract
MAP1B, a structural microtubule (MT)-associated protein highly expressed in developing neurons, plays a key role in neurite and axon extension. However, not all molecular mechanisms by which MAP1B controls MT dynamics during these processes have been revealed. Here, we show that MAP1B interacts directly with EB1 and EB3 (EBs), two core 'microtubule plus-end tracking proteins' (+TIPs), and sequesters them in the cytosol of developing neuronal cells. MAP1B overexpression reduces EBs binding to plus-ends, whereas MAP1B downregulation increases binding of EBs to MTs. These alterations in EBs behaviour lead to changes in MT dynamics, in particular overstabilization and looping, in growth cones of MAP1B-deficient neurons. This contributes to growth cone remodelling and a delay in axon outgrowth. Together, our findings define a new and crucial role of MAP1B as a direct regulator of EBs function and MT dynamics during neurite and axon extension. Our data provide a new layer of MT regulation: a classical MAP, which binds to the MT lattice and not to the end, controls effective concentration of core +TIPs thereby regulating MTs at their plus-ends.
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50
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Cassimeris L, Guglielmi L, Denis V, Larroque C, Martineau P. Specific in vivo labeling of tyrosinated α-tubulin and measurement of microtubule dynamics using a GFP tagged, cytoplasmically expressed recombinant antibody. PLoS One 2013; 8:e59812. [PMID: 23555790 PMCID: PMC3610906 DOI: 10.1371/journal.pone.0059812] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 02/19/2013] [Indexed: 01/05/2023] Open
Abstract
GFP-tagged proteins are used extensively as biosensors for protein localization and function, but the GFP moiety can interfere with protein properties. An alternative is to indirectly label proteins using intracellular recombinant antibodies (scFvs), but most antibody fragments are insoluble in the reducing environment of the cytosol. From a synthetic hyperstable human scFv library we isolated an anti-tubulin scFv, 2G4, which is soluble in mammalian cells when expressed as a GFP-fusion protein. Here we report the use of this GFP-tagged scFv to label microtubules in fixed and living cells. We found that 2G4-GFP localized uniformly along microtubules and did not disrupt binding of EB1, a protein that binds microtubule ends and serves as a platform for binding by a complex of proteins regulating MT polymerization. TOGp and CLIP-170 also bound microtubule ends in cells expressing 2G4-GFP. Microtubule dynamic instability, measured by tracking 2G4-GFP labeled microtubules, was nearly identical to that measured in cells expressing GFP-α-tubulin. Fluorescence recovery after photobleaching demonstrated that 2G4-GFP turns over rapidly on microtubules, similar to the turnover rates of fluorescently tagged microtubule-associated proteins. These data indicate that 2G4-GFP binds relatively weakly to microtubules, and this conclusion was confirmed in vitro. Purified 2G4 partially co-pelleted with microtubules, but a significant fraction remained in the soluble fraction, while a second anti-tubulin scFv, 2F12, was almost completely co-pelleted with microtubules. In cells, 2G4-GFP localized to most microtubules, but did not co-localize with those composed of detyrosinated α-tubulin, a post-translational modification associated with non-dynamic, more stable microtubules. Immunoblots probing bacterially expressed tubulins confirmed that 2G4 recognized α-tubulin and required tubulin’s C-terminal tyrosine residue for binding. Thus, a recombinant antibody with weak affinity for its substrate can be used as a specific intracellular biosensor that can differentiate between unmodified and post-translationally modified forms of a protein.
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Affiliation(s)
- Lynne Cassimeris
- Department of Biological Sciences, Lehigh University, Bethlehem, Pennsylvania, United States of America.
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