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Kroeger B, Manning SA, Fonseka Y, Oorschot V, Crawford SA, Ramm G, Harvey KF. Basal spot junctions of Drosophila epithelial tissues respond to morphogenetic forces and regulate Hippo signaling. Dev Cell 2024; 59:262-279.e6. [PMID: 38134928 DOI: 10.1016/j.devcel.2023.11.024] [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: 08/03/2022] [Revised: 09/08/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023]
Abstract
Organ size is controlled by numerous factors including mechanical forces, which are mediated in part by the Hippo pathway. In growing Drosophila epithelial tissues, cytoskeletal tension influences Hippo signaling by modulating the localization of key pathway proteins to different apical domains. Here, we discovered a Hippo signaling hub at basal spot junctions, which form at the basal-most point of the lateral membranes and resemble adherens junctions in protein composition. Basal spot junctions recruit the central kinase Warts via Ajuba and E-cadherin, which prevent Warts activation by segregating it from upstream Hippo pathway proteins. Basal spot junctions are prominent when tissues undergo morphogenesis and are highly sensitive to fluctuations in cytoskeletal tension. They are distinct from focal adhesions, but the latter profoundly influences basal spot junction abundance by modulating the basal-medial actomyosin network and tension experienced by spot junctions. Thus, basal spot junctions couple morphogenetic forces to Hippo pathway activity and organ growth.
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Affiliation(s)
- Benjamin Kroeger
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Melbourne, VIC 3800, Australia; Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia
| | - Samuel A Manning
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Melbourne, VIC 3800, Australia; Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia
| | - Yoshana Fonseka
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Melbourne, VIC 3800, Australia
| | - Viola Oorschot
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Melbourne, VIC 3168, Australia
| | - Simon A Crawford
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Melbourne, VIC 3168, Australia
| | - Georg Ramm
- Ramaciotti Centre for Cryo-Electron Microscopy, Monash University, Clayton, Melbourne, VIC 3168, Australia
| | - Kieran F Harvey
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Melbourne, VIC 3800, Australia; Peter MacCallum Cancer Centre, 305 Grattan St, Melbourne, VIC 3000, Australia; Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Melbourne, VIC 3010, Australia.
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2
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Cachoux VML, Balakireva M, Gracia M, Bosveld F, López-Gay JM, Maugarny A, Gaugué I, di Pietro F, Rigaud SU, Noiret L, Guirao B, Bellaïche Y. Epithelial apoptotic pattern emerges from global and local regulation by cell apical area. Curr Biol 2023; 33:4807-4826.e6. [PMID: 37827152 PMCID: PMC10681125 DOI: 10.1016/j.cub.2023.09.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 08/07/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023]
Abstract
Geometry is a fundamental attribute of biological systems, and it underlies cell and tissue dynamics. Cell geometry controls cell-cycle progression and mitosis and thus modulates tissue development and homeostasis. In sharp contrast and despite the extensive characterization of the genetic mechanisms of caspase activation, we know little about whether and how cell geometry controls apoptosis commitment in developing tissues. Here, we combined multiscale time-lapse microscopy of developing Drosophila epithelium, quantitative characterization of cell behaviors, and genetic and mechanical perturbations to determine how apoptosis is controlled during epithelial tissue development. We found that early in cell lives and well before extrusion, apoptosis commitment is linked to two distinct geometric features: a small apical area compared with other cells within the tissue and a small relative apical area with respect to the immediate neighboring cells. We showed that these global and local geometric characteristics are sufficient to recapitulate the tissue-scale apoptotic pattern. Furthermore, we established that the coupling between these two geometric features and apoptotic cells is dependent on the Hippo/YAP and Notch pathways. Overall, by exploring the links between cell geometry and apoptosis commitment, our work provides important insights into the spatial regulation of cell death in tissues and improves our understanding of the mechanisms that control cell number and tissue size.
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Affiliation(s)
- Victoire M L Cachoux
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Maria Balakireva
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Mélanie Gracia
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Floris Bosveld
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Jesús M López-Gay
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Aude Maugarny
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Isabelle Gaugué
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Florencia di Pietro
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Stéphane U Rigaud
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Lorette Noiret
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Boris Guirao
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France.
| | - Yohanns Bellaïche
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR3215, INSERM U934, Genetics and Developmental Biology, 75005 Paris, France.
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3
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Ibar C, Chinthalapudi K, Heissler SM, Irvine KD. Competition between myosin II and β H-spectrin regulates cytoskeletal tension. eLife 2023; 12:RP84918. [PMID: 37367948 DOI: 10.7554/elife.84918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023] Open
Abstract
Spectrins are membrane cytoskeletal proteins generally thought to function as heterotetramers comprising two α-spectrins and two β-spectrins. They influence cell shape and Hippo signaling, but the mechanism by which they influence Hippo signaling has remained unclear. We have investigated the role and regulation of the Drosophila β-heavy spectrin (βH-spectrin, encoded by the karst gene) in wing imaginal discs. Our results establish that βH-spectrin regulates Hippo signaling through the Jub biomechanical pathway due to its influence on cytoskeletal tension. While we find that α-spectrin also regulates Hippo signaling through Jub, unexpectedly, we find that βH-spectrin localizes and functions independently of α-spectrin. Instead, βH-spectrin co-localizes with and reciprocally regulates and is regulated by myosin. In vivo and in vitro experiments support a model in which βH-spectrin and myosin directly compete for binding to apical F-actin. This competition can explain the influence of βH-spectrin on cytoskeletal tension and myosin accumulation. It also provides new insight into how βH-spectrin participates in ratcheting mechanisms associated with cell shape change.
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Affiliation(s)
- Consuelo Ibar
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, United States
| | - Krishna Chinthalapudi
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, United States
| | - Sarah M Heissler
- Department of Physiology and Cell Biology, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University College of Medicine, Columbus, United States
| | - Kenneth D Irvine
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, United States
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4
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Meghini F, Martins T, Zhang Q, Loyer N, Trickey M, Abula Y, Yamano H, Januschke J, Kimata Y. APC/C-dependent degradation of Spd2 regulates centrosome asymmetry in Drosophila neural stem cells. EMBO Rep 2023; 24:e55607. [PMID: 36852890 PMCID: PMC10074082 DOI: 10.15252/embr.202255607] [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: 06/17/2022] [Revised: 12/31/2022] [Accepted: 01/11/2023] [Indexed: 03/01/2023] Open
Abstract
A functional centrosome is vital for the development and physiology of animals. Among numerous regulatory mechanisms of the centrosome, ubiquitin-mediated proteolysis is known to be critical for the precise regulation of centriole duplication. However, its significance beyond centrosome copy number control remains unclear. Using an in vitro screen for centrosomal substrates of the APC/C ubiquitin ligase in Drosophila, we identify several conserved pericentriolar material (PCM) components, including the inner PCM protein Spd2. We show that Spd2 levels are controlled by the interphase-specific form of APC/C, APC/CFzr , in cultured cells and developing brains. Increased Spd2 levels compromise neural stem cell-specific asymmetric PCM recruitment and microtubule nucleation at interphase centrosomes, resulting in partial randomisation of the division axis and segregation patterns of the daughter centrosome in the following mitosis. We further provide evidence that APC/CFzr -dependent Spd2 degradation restricts the amount and mobility of Spd2 at the daughter centrosome, thereby facilitating the accumulation of Polo-dependent Spd2 phosphorylation for PCM recruitment. Our study underpins the critical role of cell cycle-dependent proteolytic regulation of the PCM in stem cells.
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Affiliation(s)
| | - Torcato Martins
- Department of Genetics, University of Cambridge, Cambridge, UK
- Department of Medical Sciences, Institute of Biomedicine-iBiMED, University of Aveiro, Aveiro, Portugal
| | - Qian Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Nicolas Loyer
- School of Life Science, University of Dundee, Dundee, UK
| | | | - Yusanjiang Abula
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | | | - Jens Januschke
- School of Life Science, University of Dundee, Dundee, UK
| | - Yuu Kimata
- Department of Genetics, University of Cambridge, Cambridge, UK
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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5
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Sheppard L, Green DG, Lerchbaumer G, Rothenberg KE, Fernandez-Gonzalez R, Tepass U. The α-Catenin mechanosensing M region is required for cell adhesion during tissue morphogenesis. J Cell Biol 2023; 222:e202108091. [PMID: 36520419 PMCID: PMC9757846 DOI: 10.1083/jcb.202108091] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/08/2022] [Accepted: 11/18/2022] [Indexed: 12/23/2022] Open
Abstract
α-Catenin couples the cadherin-catenin complex to the actin cytoskeleton. The mechanosensitive α-Catenin M region undergoes conformational changes upon application of force to recruit interaction partners. Here, we took advantage of the tension landscape in the Drosophila embryo to define three different states of α-Catenin mechanosensing in support of cell adhesion. Low-, medium-, and high-tension contacts showed a corresponding recruitment of Vinculin and Ajuba, which was dependent on the α-Catenin M region. In contrast, the Afadin homolog Canoe acts in parallel to α-Catenin at bicellular low- and medium-tension junctions but requires an interaction with α-Catenin for its tension-sensitive enrichment at high-tension tricellular junctions. Individual M region domains make complex contributions to cell adhesion through their impact on interaction partner recruitment, and redundancies with the function of Canoe. Our data argue that α-Catenin and its interaction partners are part of a cooperative and partially redundant mechanoresponsive network that supports AJs remodeling during morphogenesis.
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Affiliation(s)
- Luka Sheppard
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - David G. Green
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Gerald Lerchbaumer
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Katheryn E. Rothenberg
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
- Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Canada
| | - Rodrigo Fernandez-Gonzalez
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
- Ted Rogers Centre for Heart Research, University of Toronto, Toronto, Canada
- Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Canada
| | - Ulrich Tepass
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
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6
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Ikawa K, Ishihara S, Tamori Y, Sugimura K. Attachment and detachment of cortical myosin regulates cell junction exchange during cell rearrangement in the Drosophila wing epithelium. Curr Biol 2023; 33:263-275.e4. [PMID: 36543168 DOI: 10.1016/j.cub.2022.11.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 08/12/2022] [Accepted: 11/29/2022] [Indexed: 12/24/2022]
Abstract
Epithelial cells remodel cell adhesion and change their neighbors to shape a tissue. This cellular rearrangement proceeds in three steps: the shrinkage of a junction, exchange of junctions, and elongation of the newly generated junction. Herein, by combining live imaging and physical modeling, we showed that the formation of myosin-II (myo-II) cables around the cell vertices underlies the exchange of junctions in the Drosophila wing epithelium. The local and transient detachment of myo-II from the cell cortex is regulated by the LIM domain-containing protein Jub and the tricellular septate junction protein M6. Moreover, we found that M6 shifts to the adherens junction plane on jub RNAi and that Jub is persistently retained at reconnecting junctions in m6 RNAi cells. This interplay between Jub and M6 can depend on the junction length and thereby couples the detachment of cortical myo-II cables and the shrinkage/elongation of the junction during cell rearrangement. Furthermore, we developed a mechanical model based on the wetting theory and clarified how the physical properties of myo-II cables are integrated with the junction geometry to induce the transition between the attached and detached states and support the unidirectionality of cell rearrangement. Collectively, this study elucidates the orchestration of geometry, mechanics, and signaling for exchanging junctions.
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Affiliation(s)
- Keisuke Ikawa
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan; Division of Biological Science, Graduate School of Science, Nagoya University, Aichi 464-8602, Japan.
| | - Shuji Ishihara
- Department of Integrated Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan; Universal Biology Institute, The University of Tokyo, Tokyo 113-0033, Japan
| | - Yoichiro Tamori
- Department of Molecular Oncology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Kaoru Sugimura
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo 113-0032, Japan; Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan; Universal Biology Institute, The University of Tokyo, Tokyo 113-0033, Japan; Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Chiba 277-8561, Japan.
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7
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Madhavan SM, Konieczkowski M, Bruggeman LA, DeWalt M, Nguyen JK, O'Toole JF, Sedor JR. Essential role of Wtip in mouse development and maintenance of the glomerular filtration barrier. Am J Physiol Renal Physiol 2022; 323:F272-F287. [PMID: 35862649 PMCID: PMC9394782 DOI: 10.1152/ajprenal.00051.2022] [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: 03/02/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 11/22/2022] Open
Abstract
Wilms' tumor interacting protein (Wtip) has been implicated in cell junction assembly and cell differentiation and interacts with proteins in the podocyte slit diaphragm, where it regulates podocyte phenotype. To define Wtip expression and function in the kidney, we created a Wtip-deleted mouse model using β-galactosidase-neomycin (β-geo) gene trap technology. Wtip gene trap mice were embryonic lethal, suggesting additional developmental roles outside kidney function. Using β-geo heterozygous and normal mice, Wtip expression was identified in the developing kidneys, heart, and eyes. In the kidney, expression was restricted to podocytes, which appeared initially at the capillary loop stage coinciding with terminal podocyte differentiation. Heterozygous mice had an expected lifespan and showed no evidence of proteinuria or glomerular pathology. However, heterozygous mice were more susceptible to glomerular injury than wild-type littermates and developed more significant and prolonged proteinuria in response to lipopolysaccharide or adriamycin. In normal human kidneys, WTIP expression patterns were consistent with observations in mice and were lost in glomeruli concurrent with loss of synaptopodin expression in disease. Mechanistically, we identified the Rho guanine nucleotide exchange factor 12 (ARHGEF12) as a binding partner for WTIP. ARHGEF12 was expressed in human podocytes and formed high-affinity interactions through their LIM- and PDZ-binding domains. Our findings suggest that Wtip is essential for early murine embryonic development and maintaining normal glomerular filtration barrier function, potentially regulating slit diaphragm and foot process function through Rho effector proteins.NEW & NOTEWORTHY This study characterized dynamic expression patterns of Wilms' tumor interacting protein (Wtip) and demonstrates the novel role of Wtip in murine development and maintenance of the glomerular filtration barrier.
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Affiliation(s)
- Sethu M Madhavan
- Department of Medicine, The Ohio State University, Columbus, Ohio
| | | | - Leslie A Bruggeman
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, Ohio
- Department of Nephrology, Cleveland Clinic, Cleveland, Ohio
| | - Megan DeWalt
- Department of Medicine, The Ohio State University, Columbus, Ohio
| | - Jane K Nguyen
- Department of Pathology, Cleveland Clinic, Cleveland, Ohio
| | - John F O'Toole
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, Ohio
- Department of Nephrology, Cleveland Clinic, Cleveland, Ohio
| | - John R Sedor
- Department of Inflammation and Immunity, Cleveland Clinic, Cleveland, Ohio
- Department of Nephrology, Cleveland Clinic, Cleveland, Ohio
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio
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8
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Rauskolb C, Han A, Kirichenko E, Ibar C, Irvine KD. Analysis of the Drosophila Ajuba LIM protein defines functions for distinct LIM domains. PLoS One 2022; 17:e0269208. [PMID: 35969522 PMCID: PMC9377591 DOI: 10.1371/journal.pone.0269208] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 08/01/2022] [Indexed: 01/27/2023] Open
Abstract
The Ajuba LIM protein Jub mediates regulation of Hippo signaling by cytoskeletal tension through interaction with the kinase Warts and participates in feedback regulation of junctional tension through regulation of the cytohesin Steppke. To investigate how Jub interacts with and regulates its distinct partners, we investigated the ability of Jub proteins missing different combinations of its three LIM domains to rescue jub phenotypes and to interact with α-catenin, Warts and Steppke. Multiple regions of Jub contribute to its ability to bind α-catenin and to localize to adherens junctions in Drosophila wing imaginal discs. Co-immunoprecipitation experiments in cultured cells identified a specific requirement for LIM2 for binding to Warts. However, in vivo, both LIM1 and LIM2, but not LIM3, were required for regulation of wing growth, Yorkie activity, and Warts localization. Conversely, LIM2 and LIM3, but not LIM1, were required for regulation of cell shape and Steppke localization in vivo, and for maximal Steppke binding in co-immunoprecipitation experiments. These observations identify distinct functions for the different LIM domains of Jub.
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Affiliation(s)
- Cordelia Rauskolb
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, United States of America
| | - Ahri Han
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, United States of America
| | - Elmira Kirichenko
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, United States of America
| | - Consuelo Ibar
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, United States of America
| | - Kenneth D. Irvine
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ, United States of America
- * E-mail:
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9
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Reis AH, Xiang B, Ossipova O, Itoh K, Sokol SY. Identification of the centrosomal maturation factor SSX2IP as a Wtip-binding partner by targeted proximity biotinylation. PLoS One 2021; 16:e0259068. [PMID: 34710136 PMCID: PMC8553094 DOI: 10.1371/journal.pone.0259068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/11/2021] [Indexed: 11/19/2022] Open
Abstract
Wilms tumor-1-interacting protein (Wtip) is a LIM-domain-containing adaptor that links cell junctions with actomyosin complexes and modulates actomyosin contractility and ciliogenesis in Xenopus embryos. The Wtip C-terminus with three LIM domains associates with the actin-binding protein Shroom3 and modulates Shroom3-induced apical constriction in ectoderm cells. By contrast, the N-terminal domain localizes to apical junctions in the ectoderm and basal bodies in skin multiciliated cells, but its interacting partners remain largely unknown. Targeted proximity biotinylation (TPB) using anti-GFP antibody fused to the biotin ligase BirA identified SSX2IP as a candidate protein that binds GFP-WtipN. SSX2IP, also known as Msd1 or ADIP, is a component of cell junctions, centriolar satellite protein and a targeting factor for ciliary membrane proteins. WtipN physically associated with SSX2IP and the two proteins readily formed mixed aggregates in overexpressing cells. By contrast, we observed only partial colocalization of full length Wtip and SSX2IP, suggesting that Wtip adopts a ‘closed’ conformation in the cell. Furthermore, the double depletion of Wtip and SSX2IP in early embryos uncovered the functional interaction of the two proteins during neural tube closure. Our results suggest that the association of SSX2IP and Wtip is essential for cell junction remodeling and morphogenetic processes that accompany neurulation. We propose that TPB can be a general approach that is applicable to other GFP-tagged proteins.
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Affiliation(s)
- Alice H. Reis
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Bo Xiang
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Olga Ossipova
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Keiji Itoh
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Sergei Y. Sokol
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
- * E-mail:
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10
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Pojer JM, Saiful Hilmi AJ, Kondo S, Harvey KF. Crumbs and the apical spectrin cytoskeleton regulate R8 cell fate in the Drosophila eye. PLoS Genet 2021; 17:e1009146. [PMID: 34097697 PMCID: PMC8211197 DOI: 10.1371/journal.pgen.1009146] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 06/17/2021] [Accepted: 05/11/2021] [Indexed: 12/31/2022] Open
Abstract
The Hippo pathway is an important regulator of organ growth and cell fate. In the R8 photoreceptor cells of the Drosophila melanogaster eye, the Hippo pathway controls the fate choice between one of two subtypes that express either the blue light-sensitive Rhodopsin 5 (Hippo inactive R8 subtype) or the green light-sensitive Rhodopsin 6 (Hippo active R8 subtype). The degree to which the mechanism of Hippo signal transduction and the proteins that mediate it are conserved in organ growth and R8 cell fate choice is currently unclear. Here, we identify Crumbs and the apical spectrin cytoskeleton as regulators of R8 cell fate. By contrast, other proteins that influence Hippo-dependent organ growth, such as the basolateral spectrin cytoskeleton and Ajuba, are dispensable for the R8 cell fate choice. Surprisingly, Crumbs promotes the Rhodopsin 5 cell fate, which is driven by Yorkie, rather than the Rhodopsin 6 cell fate, which is driven by Warts and the Hippo pathway, which contrasts with its impact on Hippo activity in organ growth. Furthermore, neither the apical spectrin cytoskeleton nor Crumbs appear to regulate the Hippo pathway through mechanisms that have been observed in growing organs. Together, these results show that only a subset of Hippo pathway proteins regulate the R8 binary cell fate decision and that aspects of Hippo signalling differ between growing organs and post-mitotic R8 cells.
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Affiliation(s)
- Jonathan M. Pojer
- Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
| | - Abdul Jabbar Saiful Hilmi
- Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
| | - Shu Kondo
- Laboratory of Invertebrate Genetics, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Kieran F. Harvey
- Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia
- Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
- Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
- * E-mail:
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11
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Schleicher K, Schramek D. AJUBA: A regulator of epidermal homeostasis and cancer. Exp Dermatol 2021; 30:546-559. [PMID: 33372298 DOI: 10.1111/exd.14272] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 12/09/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022]
Abstract
The epidermis, outermost layer of the skin, is constantly renewing itself through proliferative and differentiation processes. These processes are vital to maintain proper epidermal integrity during skin development and homeostasis and for preventing skin diseases and cancers. The biological mechanisms that permit this balancing act are vast, where individual pathway regulators are known, but the exact regulatory control and cross-talk between simultaneously turning one biological pathway on and an opposing one off remain elusive. This review explores the diverse roles the scaffolding protein AJUBA plays during epidermal homeostasis and cancer. Initially identified for its role in promoting meiotic progression in oocytes through Grb2 and MAP kinase activity, AJUBA also maintains cytoskeletal tension permitting epidermal tissue development and responds to retinoic acid committing cells to initiate development of surface epidermal layer. AJUBA regulates proliferation of skin stem cells through Hippo and Wnt signalling and encourages mitotic commitment through Aurora-A, Aurora-B and CDK1. In addition, AJUBA also induces epidermal differentiation to maintain appropriate epidermal thickness and barrier function by activating Notch signalling and stabilizing catenins and actin during cellular remodelling. AJUBA also plays an imperative context-dependent tumor-promoting and tumor-suppressive role within epithelial cancers. AJUBA's abundant roles within the epidermis signify its importance as a molecular switchboard, vetting multiple signalling pathways to control epidermal biology.
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Affiliation(s)
- Krista Schleicher
- Molecular, Structural and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada.,Faculty of Medicine, Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Daniel Schramek
- Molecular, Structural and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada.,Faculty of Medicine, Molecular Genetics, University of Toronto, Toronto, ON, Canada
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12
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López-Gay JM, Nunley H, Spencer M, di Pietro F, Guirao B, Bosveld F, Markova O, Gaugue I, Pelletier S, Lubensky DK, Bellaïche Y. Apical stress fibers enable a scaling between cell mechanical response and area in epithelial tissue. Science 2020; 370:370/6514/eabb2169. [PMID: 33060329 DOI: 10.1126/science.abb2169] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 08/13/2020] [Indexed: 12/14/2022]
Abstract
Biological systems tailor their properties and behavior to their size throughout development and in numerous aspects of physiology. However, such size scaling remains poorly understood as it applies to cell mechanics and mechanosensing. By examining how the Drosophila pupal dorsal thorax epithelium responds to morphogenetic forces, we found that the number of apical stress fibers (aSFs) anchored to adherens junctions scales with cell apical area to limit larger cell elongation under mechanical stress. aSFs cluster Hippo pathway components, thereby scaling Hippo signaling and proliferation with area. This scaling is promoted by tricellular junctions mediating an increase in aSF nucleation rate and lifetime in larger cells. Development, homeostasis, and repair entail epithelial cell size changes driven by mechanical forces; our work highlights how, in turn, mechanosensitivity scales with cell size.
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Affiliation(s)
- Jesús M López-Gay
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, F-75248 Paris Cedex 05, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, F-75005 Paris, France
| | - Hayden Nunley
- Biophysics Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Meryl Spencer
- Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Florencia di Pietro
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, F-75248 Paris Cedex 05, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, F-75005 Paris, France
| | - Boris Guirao
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, F-75248 Paris Cedex 05, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, F-75005 Paris, France
| | - Floris Bosveld
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, F-75248 Paris Cedex 05, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, F-75005 Paris, France
| | - Olga Markova
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, F-75248 Paris Cedex 05, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, F-75005 Paris, France
| | - Isabelle Gaugue
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, F-75248 Paris Cedex 05, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, F-75005 Paris, France
| | - Stéphane Pelletier
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, F-75248 Paris Cedex 05, France.,Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, F-75005 Paris, France
| | - David K Lubensky
- Biophysics Program, University of Michigan, Ann Arbor, MI 48109, USA. .,Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yohanns Bellaïche
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, F-75248 Paris Cedex 05, France. .,Sorbonne Universités, UPMC Univ Paris 06, CNRS, CNRS UMR 3215, INSERM U934, F-75005 Paris, France
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13
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Ajuba: An emerging signal transducer in oncogenesis. Pharmacol Res 2019; 151:104546. [PMID: 31740385 DOI: 10.1016/j.phrs.2019.104546] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 11/05/2019] [Accepted: 11/13/2019] [Indexed: 12/12/2022]
Abstract
The LIM protein Ajuba contains an unstructured proline/glycine-rich preLIM region in the N terminus and conserved tandem LIM motifs in the C terminus. Additionally, Ajuba contains both nuclear export sequences (NES) and nuclear localization sequences (NLS), which enable Ajuba shuttle between the cytoplasm and the nucleus. Thus, Ajuba can act as a versatile scaffold participating in assembly of variety of protein complexes to execute multiple cellular functions including cell adhesion, motility, mitosis, survival, gene expression, microRNA processing and mechanical force sensing. Numerous studies have demonstrated that Ajuba plays important roles in oncogenesis and progression by regulating major signalling pathways such as Wnt, RAS/ERK, JAK/STAT and Hippo, and by acting as a co-regulator of key transcription factors such as Snail, Sp1 and nuclear hormone receptors. Clinically, Ajuba is highly expressed in various types of tumors and can be a marker for prognosis and diagnosis. In this review, we aim to summarize the up-to-date literatures on the signaling pathways mediated by Ajuba and its associated protein complexes in oncogenesis, and to discuss Ajuba as a potential target for new therapeutics to treat cancers.
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14
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Sarpal R, Yan V, Kazakova L, Sheppard L, Yu JC, Fernandez-Gonzalez R, Tepass U. Role of α-Catenin and its mechanosensing properties in regulating Hippo/YAP-dependent tissue growth. PLoS Genet 2019; 15:e1008454. [PMID: 31697683 PMCID: PMC6863567 DOI: 10.1371/journal.pgen.1008454] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 11/19/2019] [Accepted: 10/01/2019] [Indexed: 01/08/2023] Open
Abstract
α-catenin is a key protein of adherens junctions (AJs) with mechanosensory properties. It also acts as a tumor suppressor that limits tissue growth. Here we analyzed the function of Drosophila α-Catenin (α-Cat) in growth regulation of the wing epithelium. We found that different α-Cat levels led to a differential activation of Hippo/Yorkie or JNK signaling causing tissue overgrowth or degeneration, respectively. α-Cat can modulate Yorkie-dependent tissue growth through recruitment of Ajuba, a negative regulator of Hippo signaling to AJs but also through a mechanism independent of Ajuba recruitment to AJs. Both mechanosensory regions of α-Cat, the M region and the actin-binding domain (ABD), contribute to growth regulation. Whereas M is dispensable for α-Cat function in the wing, individual M domains (M1, M2, M3) have opposing effects on growth regulation. In particular, M1 limits Ajuba recruitment. Loss of M1 causes Ajuba hyper-recruitment to AJs, promoting tissue-tension independent overgrowth. Although M1 binds Vinculin, Vinculin is not responsible for this effect. Moreover, disruption of mechanosensing of the α-Cat ABD affects tissue growth, with enhanced actin interactions stabilizing junctions and leading to tissue overgrowth. Together, our findings indicate that α-Cat acts through multiple mechanisms to control tissue growth, including regulation of AJ stability, mechanosensitive Ajuba recruitment, and dynamic direct F-actin interactions. We explore the regulation of tissue and organ size which is an important consideration in normal development and health. During development, tissues reach specific sizes in proportion to the rest of the body. Uncontrolled growth can lead to malformations or promote tumor growth. Recent findings have emphasized an important role for mechanical cues in the regulation of tissue growth. Mechanical signals can, for example, arise from cytoskeletal contraction that increases tension, or from compression due to proliferation and a resulting increase in cell density that would lower tension. Mechanosensory molecules that are sensitive to changes in tissue tension can convert mechanical cues into biochemical signals that enhance or slow proliferation or cell death to adjust overall tissue size. One such mechanosensory molecule is α-Catenin which is a key component of cell adhesion structures that physically link cells together and couples these structures to the cytoskeleton within cells. We clarify several molecular parameters of how α-Catenin regulates signalling pathways that control cell proliferation and cell death.
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Affiliation(s)
- Ritu Sarpal
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Victoria Yan
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Lidia Kazakova
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Luka Sheppard
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Jessica C. Yu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Rodrigo Fernandez-Gonzalez
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
- Developmental and Stem Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ulrich Tepass
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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15
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Rauskolb C, Cervantes E, Madere F, Irvine KD. Organization and function of tension-dependent complexes at adherens junctions. J Cell Sci 2019; 132:jcs.224063. [PMID: 30837288 DOI: 10.1242/jcs.224063] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 02/22/2019] [Indexed: 12/17/2022] Open
Abstract
Adherens junctions provide attachments between neighboring epithelial cells and a physical link to the cytoskeleton, which enables them to sense and transmit forces and to initiate biomechanical signaling. Examination of the Ajuba LIM protein Jub in Drosophila embryos revealed that it is recruited to adherens junctions in tissues experiencing high levels of myosin activity, and that the pattern of Jub recruitment varies depending upon how tension is organized. In cells with high junctional myosin, Jub is recruited to puncta near intercellular vertices, which are distinct from Ena-containing puncta, but can overlap Vinc-containing puncta. We identify roles for Jub in modulating tension and cellular organization, which are shared with the cytohesin Step, and the cytohesin adapter Sstn, and show that Jub and Sstn together recruit Step to adherens junctions under tension. Our observations establish Jub as a reporter of tension experienced at adherens junctions, and identify distinct types of tension-dependent and tension-independent junctional complexes. They also identify a role for Jub in mediating a feedback loop that modulates the distribution of tension and cellular organization in epithelia.
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Affiliation(s)
- Cordelia Rauskolb
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Estelle Cervantes
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Ferralita Madere
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Kenneth D Irvine
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
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16
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Alégot H, Markosian C, Rauskolb C, Yang J, Kirichenko E, Wang YC, Irvine KD. Recruitment of Jub by α-catenin promotes Yki activity and Drosophila wing growth. J Cell Sci 2019; 132:jcs.222018. [PMID: 30659113 DOI: 10.1242/jcs.222018] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 01/07/2019] [Indexed: 12/29/2022] Open
Abstract
The Hippo signaling network controls organ growth through YAP family transcription factors, including the Drosophila Yorkie protein. YAP activity is responsive to both biochemical and biomechanical cues, with one key input being tension within the F-actin cytoskeleton. Several potential mechanisms for the biomechanical regulation of YAP proteins have been described, including tension-dependent recruitment of Ajuba family proteins, which inhibit kinases that inactivate YAP proteins, to adherens junctions. Here, we investigate the mechanism by which the Drosophila Ajuba family protein Jub is recruited to adherens junctions, and the contribution of this recruitment to the regulation of Yorkie. We identify α-catenin as the mechanotransducer responsible for tension-dependent recruitment of Jub by identifying a region of α-catenin that associates with Jub, and by identifying a region, which when deleted, allows constitutive, tension-independent recruitment of Jub. We also show that increased Jub recruitment to α-catenin is associated with increased Yorkie activity and wing growth, even in the absence of increased cytoskeletal tension. Our observations establish α-catenin as a multi-functional mechanotransducer and confirm Jub recruitment to α-catenin as a key contributor to biomechanical regulation of Hippo signaling.
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Affiliation(s)
- Herve Alégot
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway NJ 08854 USA
| | - Christopher Markosian
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway NJ 08854 USA
| | - Cordelia Rauskolb
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway NJ 08854 USA
| | - Janice Yang
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway NJ 08854 USA
| | - Elmira Kirichenko
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway NJ 08854 USA
| | - Yu-Chiun Wang
- Laboratory for Epithelial Morphogenesis, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Hyogo 650-0047, Japan.,RIKEN Center for Developmental Biology (CDB), Kobe, Hyogo 650-0047, Japan
| | - Kenneth D Irvine
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway NJ 08854 USA
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17
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Pan Y, Alégot H, Rauskolb C, Irvine KD. The dynamics of Hippo signaling during Drosophila wing development. Development 2018; 145:dev165712. [PMID: 30254143 PMCID: PMC6215397 DOI: 10.1242/dev.165712] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 09/10/2018] [Indexed: 12/11/2022]
Abstract
Tissue growth needs to be properly controlled for organs to reach their correct size and shape, but the mechanisms that control growth during normal development are not fully understood. We report here that the activity of the Hippo signaling transcriptional activator Yorkie gradually decreases in the central region of the developing Drosophila wing disc. Spatial and temporal changes in Yorkie activity can be explained by changes in cytoskeletal tension and biomechanical regulators of Hippo signaling. These changes in cellular biomechanics correlate with changes in cell density, and experimental manipulations of cell density are sufficient to alter biomechanical Hippo signaling and Yorkie activity. We also relate the pattern of Yorkie activity in older discs to patterns of cell proliferation. Our results establish that spatial and temporal patterns of Hippo signaling occur during wing development, that these patterns depend upon cell-density modulated tissue mechanics and that they contribute to the regulation of wing cell proliferation.
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Affiliation(s)
- Yuanwang Pan
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Herve Alégot
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Cordelia Rauskolb
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
| | - Kenneth D Irvine
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854, USA
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18
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Razzell W, Bustillo ME, Zallen JA. The force-sensitive protein Ajuba regulates cell adhesion during epithelial morphogenesis. J Cell Biol 2018; 217:3715-3730. [PMID: 30006462 PMCID: PMC6168262 DOI: 10.1083/jcb.201801171] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 05/16/2018] [Accepted: 06/19/2018] [Indexed: 12/11/2022] Open
Abstract
The reorganization of cells in response to mechanical forces converts simple epithelial sheets into complex tissues of various shapes and dimensions. Epithelial integrity is maintained throughout tissue remodeling, but the mechanisms that regulate dynamic changes in cell adhesion under tension are not well understood. In Drosophila melanogaster, planar polarized actomyosin forces direct spatially organized cell rearrangements that elongate the body axis. We show that the LIM-domain protein Ajuba is recruited to adherens junctions in a tension-dependent fashion during axis elongation. Ajuba localizes to sites of myosin accumulation at adherens junctions within seconds, and the force-sensitive localization of Ajuba requires its N-terminal domain and two of its three LIM domains. We demonstrate that Ajuba stabilizes adherens junctions in regions of high tension during axis elongation, and that Ajuba activity is required to maintain cell adhesion during cell rearrangement and epithelial closure. These results demonstrate that Ajuba plays an essential role in regulating cell adhesion in response to mechanical forces generated by epithelial morphogenesis.
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Affiliation(s)
- William Razzell
- Howard Hughes Medical Institute and Developmental Biology Program, Sloan Kettering Institute, New York, NY
| | - Maria E Bustillo
- Howard Hughes Medical Institute and Developmental Biology Program, Sloan Kettering Institute, New York, NY
- Weill Cornell Graduate School of Medical Sciences, New York, NY
| | - Jennifer A Zallen
- Howard Hughes Medical Institute and Developmental Biology Program, Sloan Kettering Institute, New York, NY
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19
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Abstract
Mitosis is controlled by reversible protein phosphorylation involving specific kinases and phosphatases. A handful of major mitotic protein kinases, such as the cyclin B-CDK1 complex, the Aurora kinases, and Polo-like kinase 1 (PLK1), cooperatively regulate distinct mitotic processes. Research has identified proteins and mechanisms that integrate these kinases into signaling cascades that guide essential mitotic events. These findings have important implications for our understanding of the mechanisms of mitotic regulation and may advance the development of novel antimitotic drugs. We review collected evidence that in vertebrates, the Aurora kinases serve as catalytic subunits of distinct complexes formed with the four scaffold proteins Bora, CEP192, INCENP, and TPX2, which we deem "core" Aurora cofactors. These complexes and the Aurora-PLK1 cascades organized by Bora, CEP192, and INCENP control crucial aspects of mitosis and all pathways of spindle assembly. We compare the mechanisms of Aurora activation in relation to the different spindle assembly pathways and draw a functional analogy between the CEP192 complex and the chromosomal passenger complex that may reflect the coevolution of centrosomes, kinetochores, and the actomyosin cleavage apparatus. We also analyze the roles and mechanisms of Aurora-PLK1 signaling in the cell and centrosome cycles and in the DNA damage response.
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Affiliation(s)
- Vladimir Joukov
- N.N. Petrov National Medical Research Center of Oncology, Saint-Petersburg 197758, Russian Federation.
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20
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Chu CW, Xiang B, Ossipova O, Ioannou A, Sokol SY. The Ajuba family protein Wtip regulates actomyosin contractility during vertebrate neural tube closure. J Cell Sci 2018; 131:jcs.213884. [PMID: 29661847 DOI: 10.1242/jcs.213884] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/06/2018] [Indexed: 12/16/2022] Open
Abstract
Ajuba family proteins are implicated in the assembly of cell junctions and have been reported to antagonize Hippo signaling in response to cytoskeletal tension. To assess the role of these proteins in actomyosin contractility, we examined the localization and function of Wtip, a member of the Ajuba family, in Xenopus early embryos. Targeted in vivo depletion of Wtip inhibited apical constriction in neuroepithelial cells and elicited neural tube defects. Fluorescent protein-tagged Wtip showed predominant punctate localization along the cell junctions in the epidermis and a linear junctional pattern in the neuroectoderm. In cells undergoing Shroom3-induced apical constriction, the punctate distribution was reorganized into a linear pattern. Conversely, the linear junctional pattern of Wtip in neuroectoderm changed to a more punctate distribution in cells with reduced myosin II activity. The C-terminal fragment of Wtip physically associated with Shroom3 and interfered with Shroom3 activity and neural fold formation. We therefore propose that Wtip is a tension-sensitive cytoskeletal adaptor that regulates apical constriction during vertebrate neurulation.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Chih-Wen Chu
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Bo Xiang
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Olga Ossipova
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Andriani Ioannou
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Sergei Y Sokol
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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21
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Huang Y, Li T, Ems-McClung SC, Walczak CE, Prigent C, Zhu X, Zhang X, Zheng Y. Aurora A activation in mitosis promoted by BuGZ. J Cell Biol 2017; 217:107-116. [PMID: 29074706 PMCID: PMC5748987 DOI: 10.1083/jcb.201706103] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Revised: 09/22/2017] [Accepted: 09/27/2017] [Indexed: 12/25/2022] Open
Abstract
Mitotic spindle component BuGZ is known to undergo phase separation. Huang et al. show that BuGZ promotes Aurora A phosphorylation and activation and that this is inhibited when BuGZ phase separation is disrupted. Protein phase separation or coacervation has emerged as a potential mechanism to regulate biological functions. We have shown that coacervation of a mostly unstructured protein, BuGZ, promotes assembly of spindle and its matrix. BuGZ in the spindle matrix binds and concentrates tubulin to promote microtubule (MT) assembly. It remains unclear, however, whether BuGZ could regulate additional proteins to promote spindle assembly. In this study, we report that BuGZ promotes Aurora A (AurA) activation in vitro. Depletion of BuGZ in cells reduces the amount of phosphorylated AurA on spindle MTs. BuGZ also enhances MCAK phosphorylation. The two zinc fingers in BuGZ directly bind to the kinase domain of AurA, which allows AurA to incorporate into the coacervates formed by BuGZ in vitro. Importantly, mutant BuGZ that disrupts the coacervation activity in vitro fails to promote AurA phosphorylation in Xenopus laevis egg extracts. These results suggest that BuGZ coacervation promotes AurA activation in mitosis.
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Affiliation(s)
- Yuejia Huang
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD
| | - Teng Li
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD.,Institute of Basic Medical Sciences, National Center of Biomedical Analysis, Beijing, China
| | | | | | - Claude Prigent
- Institut de Génétique et Développement de Rennes, Equipe laboratoryélisée Ligue Nationale Contre la Cancer 2014-2017, Centre National de la Recherche Scientifique, Université Rennes 1, Rennes, France
| | - Xueliang Zhu
- State Key Laboratory of Cell Biology, Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xuemin Zhang
- Institute of Basic Medical Sciences, National Center of Biomedical Analysis, Beijing, China
| | - Yixian Zheng
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD
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22
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Pan Y, Heemskerk I, Ibar C, Shraiman BI, Irvine KD. Differential growth triggers mechanical feedback that elevates Hippo signaling. Proc Natl Acad Sci U S A 2016; 113:E6974-E6983. [PMID: 27791172 PMCID: PMC5111668 DOI: 10.1073/pnas.1615012113] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mechanical stress can influence cell proliferation in vitro, but whether it makes a significant contribution to growth control in vivo, and how it is modulated and experienced by cells within developing tissues, has remained unclear. Here we report that differential growth reduces cytoskeletal tension along cell junctions within faster-growing cells. We propose a theoretical model to explain the observed reduction of tension within faster-growing clones, supporting it by computer simulations based on a generalized vertex model. This reduced tension modulates a biomechanical Hippo pathway, decreasing recruitment of Ajuba LIM protein and the Hippo pathway kinase Warts, and decreasing the activity of the growth-promoting transcription factor Yorkie. These observations provide a specific mechanism for a mechanical feedback that contributes to evenly distributed growth, and we show that genetically suppressing mechanical feedback alters patterns of cell proliferation in the developing Drosophila wing. By providing experimental support for the induction of mechanical stress by differential growth, and a molecular mechanism linking this stress to the regulation of growth in developing organs, our results confirm and extend the mechanical feedback hypothesis.
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Affiliation(s)
- Yuanwang Pan
- Howard Hughes Medical Institute, Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
| | - Idse Heemskerk
- Kavli Institute of Theoretical Physics, University of California, Santa Barbara, CA 93101
| | - Consuelo Ibar
- Howard Hughes Medical Institute, Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854
| | - Boris I Shraiman
- Kavli Institute of Theoretical Physics, University of California, Santa Barbara, CA 93101
| | - Kenneth D Irvine
- Howard Hughes Medical Institute, Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854;
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23
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Asteriti IA, De Mattia F, Guarguaglini G. Cross-Talk between AURKA and Plk1 in Mitotic Entry and Spindle Assembly. Front Oncol 2015; 5:283. [PMID: 26779436 PMCID: PMC4688340 DOI: 10.3389/fonc.2015.00283] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/30/2015] [Indexed: 12/21/2022] Open
Abstract
The Aurora kinase A (AURKA) is involved in different aspects of mitotic control, from mitotic entry to cytokinesis. Consistent with its pleiotropic roles, several AURKA interactors are able to modulate its activity, the best characterized being the microtubule-binding protein TPX2, the centrosomal protein Cep192, and Bora. Bora has been described as an essential cofactor of AURKA for phosphorylation-mediated activation of the mitotic kinase polo-like kinase 1 (Plk1) at the G2/M transition. A complex AURKA/Plk1 signaling axis is emerging, with multiple involved actors; recent data suggest that this control network is not restricted to mitotic entry only, but operates throughout mitosis. Here, we integrate available data from the literature to depict the complex interplay between AURKA and Plk1 in G2 and mitosis and how it contributes to their mitotic functions. We will particularly focus on how the activity of specifically localized AURKA/Plk1 pools is modulated in time and space by their reciprocal regulation to ensure the timely and coordinated unfolding of downstream mitotic events.
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Affiliation(s)
- Italia Anna Asteriti
- Institute of Molecular Biology and Pathology, National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome , Rome , Italy
| | - Fabiola De Mattia
- Institute of Molecular Biology and Pathology, National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome , Rome , Italy
| | - Giulia Guarguaglini
- Institute of Molecular Biology and Pathology, National Research Council (CNR), c/o Department of Biology and Biotechnology, Sapienza University of Rome , Rome , Italy
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Chen JWC, Barker AR, Wakefield JG. The Ran Pathway in Drosophila melanogaster Mitosis. Front Cell Dev Biol 2015; 3:74. [PMID: 26636083 PMCID: PMC4659922 DOI: 10.3389/fcell.2015.00074] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 11/09/2015] [Indexed: 11/29/2022] Open
Abstract
Over the last two decades, the small GTPase Ran has emerged as a central regulator of both mitosis and meiosis, particularly in the generation, maintenance, and regulation of the microtubule (MT)-based bipolar spindle. Ran-regulated pathways in mitosis bear many similarities to the well-characterized functions of Ran in nuclear transport and, as with transport, the majority of these mitotic effects are mediated through affecting the physical interaction between karyopherins and Spindle Assembly Factors (SAFs)—a loose term describing proteins or protein complexes involved in spindle assembly through promoting nucleation, stabilization, and/or depolymerization of MTs, through anchoring MTs to specific structures such as centrosomes, chromatin or kinetochores, or through sliding MTs along each other to generate the force required to achieve bipolarity. As such, the Ran-mediated pathway represents a crucial functional module within the wider spindle assembly landscape. Research into mitosis using the model organism Drosophila melanogaster has contributed substantially to our understanding of centrosome and spindle function. However, in comparison to mammalian systems, very little is known about the contribution of Ran-mediated pathways in Drosophila mitosis. This article sets out to summarize our understanding of the roles of the Ran pathway components in Drosophila mitosis, focusing on the syncytial blastoderm embryo, arguing that it can provide important insights into the conserved functions on Ran during spindle formation.
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Affiliation(s)
- Jack W C Chen
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Amy R Barker
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK ; Centre for Microvascular Research, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London London, UK
| | - James G Wakefield
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
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Localization of Hippo signalling complexes and Warts activation in vivo. Nat Commun 2015; 6:8402. [PMID: 26420589 PMCID: PMC4598633 DOI: 10.1038/ncomms9402] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 08/19/2015] [Indexed: 01/20/2023] Open
Abstract
Hippo signalling controls organ growth and cell fate by regulating the activity of the kinase Warts. Multiple Hippo pathway components localize to apical junctions in epithelial cells, but the spatial and functional relationships among components have not been clarified, nor is it known where Warts activation occurs. We report here that Hippo pathway components in Drosophila wing imaginal discs are organized into distinct junctional complexes, including separate distributions for Salvador, Expanded, Warts and Hippo. These complexes are reorganized on Hippo pathway activation, when Warts shifts from associating with its inhibitor Jub to its activator Expanded, and Hippo concentrates at Salvador sites. We identify mechanisms promoting Warts relocalization, and using a phospho-specific antisera and genetic manipulations, identify where Warts activation occurs: at apical junctions where Expanded, Salvador, Hippo and Warts overlap. Our observations define spatial relationships among Hippo signalling components and establish the functional importance of their localization to Warts activation. Components of the Hippo signalling pathway localize to apical junctions in epithelial cells, where they regulate growth in response to mechanical and biochemical cues. Sun et al. show that these proteins are organized into distinct junctional complexes, which reorganize up on Hippo pathway activation.
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Shagisultanova E, Dunbrack RL, Golemis EA. Issues in interpreting the in vivo activity of Aurora-A. Expert Opin Ther Targets 2014; 19:187-200. [PMID: 25384454 DOI: 10.1517/14728222.2014.981154] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Based on its role as a mitotic regulatory kinase, overexpressed and associated with aneuploidy in cancer, small-molecule inhibitors have been developed for Aurora-A (AURKA) kinase. In preclinical and clinical assessments, these agents have shown efficacy in inducing stable disease or therapeutic response. In optimizing the use of Aurora-A inhibitors, it is critical to have robust capacity to measure the kinase activity of Aurora-A in tumors. AREAS COVERED We provide an overview of molecular mechanisms of mitotic and non-mitotic activation of Aurora-A kinase, and interaction of Aurora-A with its regulatory partners. Typically, Aurora-A activity is measured by use of phospho-antibodies targeting an autophosphorylated T288 epitope. However, recent studies have identified alternative means of Aurora-A activation control, including allosteric regulation by partners, phosphorylation on alternative activating residues (S51, S98), dephosphorylation on inhibitory sites (S342) and T288 phosphorylation by alternative kinases such as Pak enzymes. Additional work has shown that the relative abundance of Aurora-A partners can affect the activity of Aurora-A inhibitors, and that Aurora-A activation also occurs in interphase cells. EXPERT OPINION Taken together, this work suggests the need for comprehensive analysis of Aurora-A activity and expression of Aurora-A partners in order to stratify patients for likely therapeutic response.
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Affiliation(s)
- Elena Shagisultanova
- Fox Chase Cancer Center, Department of Medical Oncology , Philadelphia, PA 19111 , USA
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Cytoskeletal tension inhibits Hippo signaling through an Ajuba-Warts complex. Cell 2014; 158:143-156. [PMID: 24995985 DOI: 10.1016/j.cell.2014.05.035] [Citation(s) in RCA: 261] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 02/18/2014] [Accepted: 05/08/2014] [Indexed: 11/21/2022]
Abstract
Mechanical forces have been proposed to modulate organ growth, but a molecular mechanism that links them to growth regulation in vivo has been lacking. We report that increasing tension within the cytoskeleton increases Drosophila wing growth, whereas decreasing cytoskeletal tension decreases wing growth. These changes in growth can be accounted for by changes in the activity of Yorkie, a transcription factor regulated by the Hippo pathway. The influence of myosin activity on Yorkie depends genetically on the Ajuba LIM protein Jub, a negative regulator of Warts within the Hippo pathway. We further show that Jub associates with α-catenin and that its localization to adherens junctions and association with α-catenin are promoted by cytoskeletal tension. Jub recruits Warts to junctions in a tension-dependent manner. Our observations delineate a mechanism that links cytoskeletal tension to regulation of Hippo pathway activity, providing a molecular understanding of how mechanical forces can modulate organ growth.
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Mendes Maia T, Gogendeau D, Pennetier C, Janke C, Basto R. Bug22 influences cilium morphology and the post-translational modification of ciliary microtubules. Biol Open 2014; 3:138-51. [PMID: 24414207 PMCID: PMC3925317 DOI: 10.1242/bio.20146577] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cilia and flagella are organelles essential for motility and sensing of environmental stimuli. Depending on the cell type, cilia acquire a defined set of functions and, accordingly, are built with an appropriate length and molecular composition. Several ciliary proteins display a high degree of conservation throughout evolution and mutations in ciliary genes are associated with various diseases such as ciliopathies and infertility. Here, we describe the role of the highly conserved ciliary protein, Bug22, in Drosophila. Previous studies in unicellular organisms have shown that Bug22 is required for proper cilia function, but its exact role in ciliogenesis has not been investigated yet. Null Bug22 mutant flies display cilia-associated phenotypes and nervous system defects. Furthermore, sperm differentiation is blocked at the individualization stage, due to impaired migration of the individualization machinery. Tubulin post-translational modifications (PTMs) such as polyglycylation, polyglutamylation or acetylation, are determinants of microtubule (MT) functions and stability in centrioles, cilia and neurons. We found defects in the timely incorporation of polyglycylation in sperm axonemal MTs of Bug22 mutants. In addition, we found that depletion of human Bug22 in RPE1 cells resulted in the appearance of longer cilia and reduced axonemal polyglutamylation. Our work identifies Bug22 as a protein that plays a conserved role in the regulation of PTMs of the ciliary axoneme.
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Abstract
Wounding, apoptosis, or infection can trigger a proliferative response in neighboring cells to replace damaged tissue. Studies in Drosophila have implicated c-Jun amino-terminal kinase (JNK)-dependent activation of Yorkie (Yki) as essential to regeneration-associated growth, as well as growth associated with neoplastic tumors. Yki is a transcriptional coactivator that is inhibited by Hippo signaling, a conserved pathway that regulates growth. We identified a conserved mechanism by which JNK regulated Hippo signaling. Genetic studies in Drosophila identified Jub (also known as Ajuba LIM protein) as required for JNK-mediated activation of Yki and showed that Jub contributed to wing regeneration after wounding and to tumor growth. Biochemical studies revealed that JNK promoted the phosphorylation of Ajuba family proteins in both Drosophila and mammalian cells. Binding studies in mammalian cells indicated that JNK increased binding between the Ajuba family proteins LIMD1 or WTIP and LATS1, a kinase within the Hippo pathway that inhibits the Yki homolog YAP. Moreover, JNK promoted binding of LIMD1 and LATS1 through direct phosphorylation of LIMD1. These results identify Ajuba family proteins as a conserved link between JNK and Hippo signaling, and imply that JNK increases Yki and YAP activity by promoting the binding of Ajuba family proteins to Warts and LATS.
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Affiliation(s)
- Gongping Sun
- Howard Hughes Medical Institute, Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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30
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Nikonova AS, Astsaturov I, Serebriiskii IG, Dunbrack RL, Golemis EA. Aurora A kinase (AURKA) in normal and pathological cell division. Cell Mol Life Sci 2013; 70:661-87. [PMID: 22864622 PMCID: PMC3607959 DOI: 10.1007/s00018-012-1073-7] [Citation(s) in RCA: 321] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/05/2012] [Accepted: 06/21/2012] [Indexed: 12/20/2022]
Abstract
Temporally and spatially controlled activation of the Aurora A kinase (AURKA) regulates centrosome maturation, entry into mitosis, formation and function of the bipolar spindle, and cytokinesis. Genetic amplification and mRNA and protein overexpression of Aurora A are common in many types of solid tumor, and associated with aneuploidy, supernumerary centrosomes, defective mitotic spindles, and resistance to apoptosis. These properties have led Aurora A to be considered a high-value target for development of cancer therapeutics, with multiple agents currently in early-phase clinical trials. More recently, identification of additional, non-mitotic functions and means of activation of Aurora A during interphase neurite elongation and ciliary resorption have significantly expanded our understanding of its function, and may offer insights into the clinical performance of Aurora A inhibitors. Here we review the mitotic and non-mitotic functions of Aurora A, discuss Aurora A regulation in the context of protein structural information, and evaluate progress in understanding and inhibiting Aurora A in cancer.
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Affiliation(s)
- Anna S. Nikonova
- Program in Developmental Therapeutics, Fox Chase Cancer Center, W406, 333 Cottman Ave., Philadelphia, PA 19111 USA
| | - Igor Astsaturov
- Program in Developmental Therapeutics, Fox Chase Cancer Center, W406, 333 Cottman Ave., Philadelphia, PA 19111 USA
| | - Ilya G. Serebriiskii
- Program in Developmental Therapeutics, Fox Chase Cancer Center, W406, 333 Cottman Ave., Philadelphia, PA 19111 USA
| | - Roland L. Dunbrack
- Program in Developmental Therapeutics, Fox Chase Cancer Center, W406, 333 Cottman Ave., Philadelphia, PA 19111 USA
| | - Erica A. Golemis
- Program in Developmental Therapeutics, Fox Chase Cancer Center, W406, 333 Cottman Ave., Philadelphia, PA 19111 USA
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Karess RE, Wassmann K, Rahmani Z. New insights into the role of BubR1 in mitosis and beyond. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:223-73. [PMID: 24016527 DOI: 10.1016/b978-0-12-407694-5.00006-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BubR1 is a critical component of the spindle assembly checkpoint, the surveillance mechanism that helps maintain the high fidelity of mitotic chromosome segregation by preventing cells from initiating anaphase if one or more kinetochores are not attached to the spindle. BubR1 also helps promote the establishment of stable kinetochore-microtubule attachments during prometaphase. In this chapter, we review the structure, functions, and regulation of BubR1 in these "classical roles" at the kinetochore. We discuss its recruitment to kinetochores, its assembly into the inhibitor of anaphase progression, and the importance of its posttranslational modifications. We also consider the evidence for its participation in other roles beyond mitosis, such as the meiosis-specific processes of recombination and prophase arrest of the first meiotic division, the cellular response to DNA damage, and in the regulation of centrosome and basal body function. Finally, studies are presented linking BubR1 dysfunction or misregulation to aging and human disease, particularly cancer.
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Affiliation(s)
- Roger E Karess
- Institut Jacques Monod, UMR 7592 CNRS, Université Paris Diderot-Paris 7, Paris, France.
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Cell adhesion in Drosophila: versatility of cadherin and integrin complexes during development. Curr Opin Cell Biol 2012; 24:702-12. [PMID: 22938782 DOI: 10.1016/j.ceb.2012.07.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 07/16/2012] [Accepted: 07/26/2012] [Indexed: 01/22/2023]
Abstract
We highlight recent progress in understanding cadherin and integrin function in the model organism Drosophila. New functions for these adhesion receptors continue to be discovered in this system, emphasising the importance of cell adhesion within the developing organism and showing that the requirement for cell adhesion changes between cell types. New ways to control adhesion have been discovered, including controlling the expression and recruitment of adhesion components, their posttranslational modification, recycling and turnover. Importantly, even ubiquitous adhesion components can function differently in distinct cellular contexts.
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Reboutier D, Troadec MB, Cremet JY, Fukasawa K, Prigent C. Nucleophosmin/B23 activates Aurora A at the centrosome through phosphorylation of serine 89. ACTA ACUST UNITED AC 2012; 197:19-26. [PMID: 22451695 PMCID: PMC3317798 DOI: 10.1083/jcb.201107134] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aurora A, which is known to be activated by autophosphorylation at Thr288, is also locally activated during centrosomal maturation by nucleophosmin-mediated phosphorylation at Ser89. Aurora A (AurA) is a major mitotic protein kinase involved in centrosome maturation and spindle assembly. Nucleophosmin/B23 (NPM) is a pleiotropic nucleolar protein involved in a variety of cellular processes including centrosome maturation. In the present study, we report that NPM is a strong activator of AurA kinase activity. NPM and AurA coimmunoprecipitate and colocalize to centrosomes in G2 phase, where AurA becomes active. In contrast with previously characterized AurA activators, NPM does not trigger autophosphorylation of AurA on threonine 288. NPM induces phosphorylation of AurA on serine 89, and this phosphorylation is necessary for activation of AurA. These data were confirmed in vivo, as depletion of NPM by ribonucleic acid interference eliminated phosphorylation of CDC25B on S353 at the centrosome, indicating a local loss of AurA activity. Our data demonstrate that NPM is a strong activator of AurA kinase activity at the centrosome and support a novel mechanism of activation for AurA.
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Affiliation(s)
- David Reboutier
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche UMR6290, 35043 Rennes, France
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Mahen R, Venkitaraman AR. Pattern formation in centrosome assembly. Curr Opin Cell Biol 2012; 24:14-23. [PMID: 22245706 DOI: 10.1016/j.ceb.2011.12.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 12/21/2011] [Accepted: 12/23/2011] [Indexed: 01/01/2023]
Abstract
A striking but poorly explained feature of cell division is the ability to assemble and maintain organelles not bounded by membranes, from freely diffusing components in the cytosol. This process is driven by information transfer across biological scales such that interactions at the molecular scale allow pattern formation at the scale of the organelle. One important example of such an organelle is the centrosome, which is the main microtubule organising centre in the cell. Centrosomes consist of two centrioles surrounded by a cloud of proteins termed the pericentriolar material (PCM). Profound structural and proteomic transitions occur in the centrosome during specific cell cycle stages, underlying events such as centrosome maturation during mitosis, in which the PCM increases in size and microtubule nucleating capacity. Here we use recent insights into the spatio-temporal behaviour of key regulators of centrosomal maturation, including Polo-like kinase 1, CDK5RAP2 and Aurora-A, to propose a model for the assembly and maintenance of the PCM through the mobility and local interactions of its constituent proteins. We argue that PCM structure emerges as a pattern from decentralised self-organisation through a reaction-diffusion mechanism, with or without an underlying template, rather than being assembled from a central structural template alone. Self-organisation of this kind may have broad implications for the maintenance of mitotic structures, which, like the centrosome, exist stably as supramolecular assemblies on the micron scale, based on molecular interactions at the nanometer scale.
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Affiliation(s)
- Robert Mahen
- The Medical Research Council Cancer Cell Unit, Hutchison/MRC Research Centre, Hills Road, Cambridge, CB2 OXZ, United Kingdom.
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Moghe S, Jiang F, Miura Y, Cerny RL, Tsai MY, Furukawa M. The CUL3-KLHL18 ligase regulates mitotic entry and ubiquitylates Aurora-A. Biol Open 2011; 1:82-91. [PMID: 23213400 PMCID: PMC3507203 DOI: 10.1242/bio.2011018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The cullin-RING family of ubiquitin ligases regulates diverse cellular functions, such as cell cycle control, via ubiquitylation of specific substrates. CUL3 targets its substrates through BTB proteins. Here we show that depletion of CUL3 and the BTB protein KLHL18 causes a delay in mitotic entry. Centrosomal activation of Aurora-A, a kinase whose activity is required for entry into mitosis, is also delayed in depleted cells. Moreover, we identify Aurora-A as a KLHL18-interacting partner. Overexpression of KLHL18 and CUL3 promotes Aurora-A ubiquitylation in vivo, and the CUL3-KLHL18-ROC1 ligase ubiquitylates Aurora-A in vitro. Our study reveals that the CUL3-KLHL18 ligase is required for timely entry into mitosis, as well as for the activation of Aurora-A at centrosomes. We propose that the CUL3-KLHL18 ligase regulates mitotic entry through an Aurora-A-dependent pathway.
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Affiliation(s)
- Saili Moghe
- Eppley Institute for Research in Cancer and Allied Diseases, 987696 Nebraska Medical Center, University of Nebraska Medical Center , Omaha, NE 68198-7696 , USA
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