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Marquardt J, Chen X, Bi E. Reciprocal regulation by Elm1 and Gin4 controls septin hourglass assembly and remodeling. J Cell Biol 2024; 223:e202308143. [PMID: 38448162 PMCID: PMC10913813 DOI: 10.1083/jcb.202308143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 02/05/2024] [Accepted: 02/20/2024] [Indexed: 03/08/2024] Open
Abstract
The septin cytoskeleton is extensively regulated by posttranslational modifications, such as phosphorylation, to achieve the diversity of architectures including rings, hourglasses, and gauzes. While many of the phosphorylation events of septins have been extensively studied in the budding yeast Saccharomyces cerevisiae, the regulation of the kinases involved remains poorly understood. Here, we show that two septin-associated kinases, the LKB1/PAR-4-related kinase Elm1 and the Nim1/PAR-1-related kinase Gin4, regulate each other at two discrete points of the cell cycle. During bud emergence, Gin4 targets Elm1 to the bud neck via direct binding and phosphorylation to control septin hourglass assembly and stability. During mitosis, Elm1 maintains Gin4 localization via direct binding and phosphorylation to enable timely remodeling of the septin hourglass into a double ring. This mutual control between Gin4 and Elm1 ensures that septin architecture is assembled and remodeled in a temporally controlled manner to perform distinct functions during the cell cycle.
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Affiliation(s)
- Joseph Marquardt
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Xi Chen
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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2
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Demouchy F, Nicolle O, Michaux G, Pacquelet A. PAR-4/LKB1 prevents intestinal hyperplasia by restricting endoderm specification in Caenorhabditis elegans embryos. Development 2024; 151:dev202205. [PMID: 38078543 DOI: 10.1242/dev.202205] [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: 07/28/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024]
Abstract
The kinase PAR-4/LKB1 is a major regulator of intestinal homeostasis, which prevents polyposis in humans. Moreover, its ectopic activation is sufficient to induce polarization and formation of microvilli-like structures in intestinal cell lines. Here, we use Caenorhabditis elegans to examine the role of PAR-4 during intestinal development in vivo. We show that it is not required to establish enterocyte polarity and plays only a minor role in brush border formation. By contrast, par-4 mutants display severe deformations of the intestinal lumen as well as supernumerary intestinal cells, thereby revealing a previously unappreciated function of PAR-4 in preventing intestinal hyperplasia. The presence of supernumerary enterocytes in par-4 mutants is not due to excessive cell proliferation, but rather to the abnormal expression of the intestinal cell fate factors end-1 and elt-2 outside the E lineage. Notably, par-4 mutants also display reduced expression of end-1 and elt-2 inside the E lineage. Our work thereby unveils an essential and dual role of PAR-4, which both restricts intestinal specification to the E lineage and ensures its robust differentiation.
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Affiliation(s)
- Flora Demouchy
- University of Rennes, CNRS, IGDR (Institut de Génétique et de Développement de Rennes), UMR 6290, F-35000 Rennes, France
| | - Ophélie Nicolle
- University of Rennes, CNRS, IGDR (Institut de Génétique et de Développement de Rennes), UMR 6290, F-35000 Rennes, France
| | - Grégoire Michaux
- University of Rennes, CNRS, IGDR (Institut de Génétique et de Développement de Rennes), UMR 6290, F-35000 Rennes, France
| | - Anne Pacquelet
- University of Rennes, CNRS, IGDR (Institut de Génétique et de Développement de Rennes), UMR 6290, F-35000 Rennes, France
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3
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Marquardt J, Chen X, Bi E. Elucidating the Synergistic Role of Elm1 and Gin4 Kinases in Regulating Septin Hourglass Assembly. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566235. [PMID: 37986786 PMCID: PMC10659281 DOI: 10.1101/2023.11.08.566235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The septin cytoskeleton is extensively regulated by post-translational modifications such as phosphorylation to achieve the diversity of architectures including rings, hourglass, and gauzes. While many of the phosphorylation events of septins have been extensively studied in the budding yeast Saccharomyces cerevisiae, the regulation of the kinases involved remains poorly understood. Here we show that two septin-associated kinases, the LKB1/PAR-4-related kinase Elm1 and the Nim1/PAR-1-related kinase Gin4, regulate each other at two discrete points of the cell cycle. During bud emergence, Gin4 targets Elm1 to the bud neck via direct binding and phosphorylation to control septin hourglass assembly and stability. During mitosis, Elm1 maintains Gin4 localization via direct binding and phosphorylation to enable timely remodeling of the septin hourglass into a double ring. This unique synergy ensures that septin architecture is assembled and remodeled in a temporally controlled manner to perform distinct functions during the cell cycle.
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Affiliation(s)
- Joseph Marquardt
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
- Current affiliation: Department of Biology, Western Kentucky University, Bowling Green, KY
| | - Xi Chen
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
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4
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Borkowsky S, Gass M, Alavizargar A, Hanewinkel J, Hallstein I, Nedvetsky P, Heuer A, Krahn MP. Phosphorylation of LKB1 by PDK1 Inhibits Cell Proliferation and Organ Growth by Decreased Activation of AMPK. Cells 2023; 12:cells12050812. [PMID: 36899949 PMCID: PMC10000615 DOI: 10.3390/cells12050812] [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: 08/19/2022] [Revised: 02/24/2023] [Accepted: 03/03/2023] [Indexed: 03/08/2023] Open
Abstract
The master kinase LKB1 is a key regulator of se veral cellular processes, including cell proliferation, cell polarity and cellular metabolism. It phosphorylates and activates several downstream kinases, including AMP-dependent kinase, AMPK. Activation of AMPK by low energy supply and phosphorylation of LKB1 results in an inhibition of mTOR, thus decreasing energy-consuming processes, in particular translation and, thus, cell growth. LKB1 itself is a constitutively active kinase, which is regulated by posttranslational modifications and direct binding to phospholipids of the plasma membrane. Here, we report that LKB1 binds to Phosphoinositide-dependent kinase (PDK1) by a conserved binding motif. Furthermore, a PDK1-consensus motif is located within the kinase domain of LKB1 and LKB1 gets phosphorylated by PDK1 in vitro. In Drosophila, knockin of phosphorylation-deficient LKB1 results in normal survival of the flies, but an increased activation of LKB1, whereas a phospho-mimetic LKB1 variant displays decreased AMPK activation. As a functional consequence, cell growth as well as organism size is decreased in phosphorylation-deficient LKB1. Molecular dynamics simulations of PDK1-mediated LKB1 phosphorylation revealed changes in the ATP binding pocket, suggesting a conformational change upon phosphorylation, which in turn can alter LKB1's kinase activity. Thus, phosphorylation of LKB1 by PDK1 results in an inhibition of LKB1, decreased activation of AMPK and enhanced cell growth.
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Affiliation(s)
- Sarah Borkowsky
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149 Münster, Germany
| | - Maximilian Gass
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149 Münster, Germany
| | - Azadeh Alavizargar
- Institute of Physical Chemistry, University of Münster, Corrensstr. 28/30, 48149 Münster, Germany
| | - Johannes Hanewinkel
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149 Münster, Germany
| | - Ina Hallstein
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149 Münster, Germany
| | - Pavel Nedvetsky
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149 Münster, Germany
| | - Andreas Heuer
- Institute of Physical Chemistry, University of Münster, Corrensstr. 28/30, 48149 Münster, Germany
| | - Michael P. Krahn
- Medical Cell Biology, Medical Clinic D, University Hospital of Münster, Albert-Schweitzer Campus 1-A14, 48149 Münster, Germany
- Correspondence: ; Tel.: +49-251-8357052
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5
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Hu L, Liu M, Tang B, Li Q, Pan BS, Xu C, Lin HK. Posttranslational regulation of liver kinase B1 (LKB1) in human cancer. J Biol Chem 2023; 299:104570. [PMID: 36870679 PMCID: PMC10068580 DOI: 10.1016/j.jbc.2023.104570] [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: 01/02/2023] [Revised: 02/20/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
Liver kinase B1 (LKB1) is a serine-threonine kinase that participates in multiple cellular and biological processes, including energy metabolism, cell polarity, cell proliferation, cell migration, and many others. LKB1 is initially identified as a germline-mutated causative gene in Peutz-Jeghers syndrome (PJS) and is commonly regarded as a tumor suppressor due to frequent inactivation in a variety of cancers. LKB1 directly binds and activates its downstream kinases including the AMP-activated protein kinase (AMPK) and AMPK-related kinases by phosphorylation, which has been intensively investigated for the past decades. An increasing number of studies has uncovered the posttranslational modifications (PTMs) of LKB1 and consequent changes in its localization, activity, and interaction with substrates. The alteration in LKB1 function as a consequence of genetic mutations and aberrant upstream signaling regulation leads to tumor development and progression. Here, we review current knowledge about the mechanism of LKB1 in cancer and the contributions of PTMs, such as phosphorylation, ubiquitination, SUMOylation, acetylation, prenylation, and others, to the regulation of LKB1 function, offering new insights into the therapeutic strategies in cancer.
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Affiliation(s)
- Lanlin Hu
- Department of Oncology & Cancer Institute, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Department of Laboratory Medicine and Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China
| | - Mingxin Liu
- Department of Oncology & Cancer Institute, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China
| | - Bo Tang
- Department of Oncology & Cancer Institute, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Department of Laboratory Medicine and Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China
| | - Qiang Li
- Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, University of Electronic Science and Technology of China, Chengdu, China
| | - Bo-Syong Pan
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Chuan Xu
- Department of Oncology & Cancer Institute, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Department of Laboratory Medicine and Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China; Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
| | - Hui-Kuan Lin
- Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.
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6
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Tzavlaki K, Ohata Y, Morén A, Watanabe Y, Eriksson J, Tsuchiya M, Kubo Y, Yamamoto K, Sellin ME, Kato M, Caja L, Heldin CH, Moustakas A. The liver kinase B1 supports mammary epithelial morphogenesis by inhibiting critical factors that mediate epithelial-mesenchymal transition. J Cell Physiol 2023; 238:790-812. [PMID: 36791282 DOI: 10.1002/jcp.30975] [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: 04/01/2022] [Revised: 01/24/2023] [Accepted: 01/31/2023] [Indexed: 02/17/2023]
Abstract
The liver kinase B1 (LKB1) controls cellular metabolism and cell polarity across species. We previously established a mechanism for negative regulation of transforming growth factor β (TGFβ) signaling by LKB1. The impact of this mechanism in the context of epithelial polarity and morphogenesis remains unknown. After demonstrating that human mammary tissue expresses robust LKB1 protein levels, whereas invasive breast cancer exhibits significantly reduced LKB1 levels, we focused on mammary morphogenesis studies in three dimensional (3D) acinar organoids. CRISPR/Cas9-introduced loss-of-function mutations of STK11 (LKB1) led to profound defects in the formation of 3D organoids, resulting in amorphous outgrowth and loss of rotation of young organoids embedded in matrigel. This defect was associated with an enhanced signaling by TGFβ, including TGFβ auto-induction and induction of transcription factors that mediate epithelial-mesenchymal transition (EMT). Protein marker analysis confirmed a more efficient EMT response to TGFβ signaling in LKB1 knockout cells. Accordingly, chemical inhibition of the TGFβ type I receptor kinase largely restored the morphogenetic defect of LKB1 knockout cells. Similarly, chemical inhibition of the bone morphogenetic protein pathway or the TANK-binding kinase 1, or genetic silencing of the EMT factor SNAI1, partially restored the LKB1 knockout defect. Thus, LKB1 sustains mammary epithelial morphogenesis by limiting pathways that promote EMT. The observed downregulation of LKB1 expression in breast cancer is therefore predicted to associate with enhanced EMT induced by SNAI1 and TGFβ family members.
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Affiliation(s)
- Kalliopi Tzavlaki
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Yae Ohata
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Anita Morén
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Yukihide Watanabe
- Department of Experimental Pathology and Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Jens Eriksson
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Maiko Tsuchiya
- Department of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Department of Pathology, Teikyo University School of Medicine, Tokyo, Japan
| | - Yuki Kubo
- Department of Comprehensive Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kouhei Yamamoto
- Department of Comprehensive Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mikael E Sellin
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Mitsuyasu Kato
- Department of Experimental Pathology and Transborder Medical Research Center, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Laia Caja
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Carl-Henrik Heldin
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Aristidis Moustakas
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
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7
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Barriga EH, Alasaadi DN, Mencarelli C, Mayor R, Pichaud F. RanBP1 plays an essential role in directed migration of neural crest cells during development. Dev Biol 2022; 492:79-86. [PMID: 36206829 DOI: 10.1016/j.ydbio.2022.09.010] [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: 06/29/2021] [Revised: 09/15/2022] [Accepted: 09/23/2022] [Indexed: 11/21/2022]
Abstract
Collective cell migration is essential for embryonic development, tissue regeneration and repair, and has been implicated in pathological conditions such as cancer metastasis. It is, in part, directed by external cues that promote front-to-rear polarity in individual cells. However, our understanding of the pathways that underpin the directional movement of cells in response to external cues remains incomplete. To examine this issue we made use of neural crest cells (NC), which migrate as a collective during development to generate vital structures including bones and cartilage. Using a candidate approach, we found an essential role for Ran-binding protein 1 (RanBP1), a key effector of the nucleocytoplasmic transport pathway, in enabling directed migration of these cells. Our results indicate that RanBP1 is required for establishing front-to-rear polarity, so that NCs are able to chemotax. Moreover, our work suggests that RanBP1 function in chemotaxis involves the polarity kinase LKB1/PAR4. We envisage that regulated nuclear export of LKB1 through Ran/RanBP1 is a key regulatory step required for establishing front-to-rear polarity and thus chemotaxis, during NC collective migration.
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Affiliation(s)
- Elias H Barriga
- Cell and Developmental Biology, University College London, London, WC1E 6BT, United Kingdom; Mechanisms of Morphogenesis Lab, Instituto Gulbenkian de Ciencia, Oeiras, 2780-156, Portugal
| | - Delan N Alasaadi
- Cell and Developmental Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Chiara Mencarelli
- Laboratory for Molecular Cell Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Roberto Mayor
- Cell and Developmental Biology, University College London, London, WC1E 6BT, United Kingdom.
| | - Franck Pichaud
- Laboratory for Molecular Cell Biology, University College London, London, WC1E 6BT, United Kingdom.
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8
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Huang E, Li S. Liver Kinase B1 Functions as a Regulator for Neural Development and a Therapeutic Target for Neural Repair. Cells 2022; 11:cells11182861. [PMID: 36139438 PMCID: PMC9496952 DOI: 10.3390/cells11182861] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/02/2022] [Accepted: 09/10/2022] [Indexed: 11/16/2022] Open
Abstract
The liver kinase B1 (LKB1), also known as serine/threonine kinase 11 (STK11) and Par-4 in C. elegans, has been identified as a master kinase of AMPKs and AMPK-related kinases. LKB1 plays a crucial role in cell growth, metabolism, polarity, and tumor suppression. By interacting with the downstream signals of SAD, NUAK, MARK, and other kinases, LKB1 is critical to regulating neuronal polarization and axon branching during development. It also regulates Schwann cell function and the myelination of peripheral axons. Regulating LKB1 activity has become an attractive strategy for repairing an injured nervous system. LKB1 upregulation enhances the regenerative capacity of adult CNS neurons and the recovery of locomotor function in adult rodents with CNS axon injury. Here, we update the major cellular and molecular mechanisms of LKB1 in regulating neuronal polarization and neural development, and the implications thereof for promoting neural repair, axon regeneration, and functional recovery in adult mammals.
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9
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Ndembe G, Intini I, Perin E, Marabese M, Caiola E, Mendogni P, Rosso L, Broggini M, Colombo M. LKB1: Can We Target an Hidden Target? Focus on NSCLC. Front Oncol 2022; 12:889826. [PMID: 35646638 PMCID: PMC9131655 DOI: 10.3389/fonc.2022.889826] [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: 03/04/2022] [Accepted: 04/14/2022] [Indexed: 11/13/2022] Open
Abstract
LKB1 (liver kinase B1) is a master regulator of several processes such as metabolism, proliferation, cell polarity and immunity. About one third of non-small cell lung cancers (NSCLCs) present LKB1 alterations, which almost invariably lead to protein loss, resulting in the absence of a potential druggable target. In addition, LKB1-null tumors are very aggressive and resistant to chemotherapy, targeted therapies and immune checkpoint inhibitors (ICIs). In this review, we report and comment strategies that exploit peculiar co-vulnerabilities to effectively treat this subgroup of NSCLCs. LKB1 loss leads to an enhanced metabolic avidity, and treatments inducing metabolic stress were successful in inhibiting tumor growth in several preclinical models. Biguanides, by compromising mitochondria and reducing systemic glucose availability, and the glutaminase inhibitor telaglenastat (CB-839), inhibiting glutamate production and reducing carbon intermediates essential for TCA cycle progression, have provided the most interesting results and entered different clinical trials enrolling also LKB1-null NSCLC patients. Nutrient deprivation has been investigated as an alternative therapeutic intervention, giving rise to interesting results exploitable to design specific dietetic regimens able to counteract cancer progression. Other strategies aimed at targeting LKB1-null NSCLCs exploit its pivotal role in modulating cell proliferation and cell invasion. Several inhibitors of LKB1 downstream proteins, such as mTOR, MEK, ERK and SRK/FAK, resulted specifically active on LKB1-mutated preclinical models and, being molecules already in clinical experimentation, could be soon proposed as a specific therapy for these patients. In particular, the rational use in combination of these inhibitors represents a very promising strategy to prevent the activation of collateral pathways and possibly avoid the potential emergence of resistance to these drugs. LKB1-null phenotype has been correlated to ICIs resistance but several studies have already proposed the mechanisms involved and potential interventions. Interestingly, emerging data highlighted that LKB1 alterations represent positive determinants to the new KRAS specific inhibitors response in KRAS co-mutated NSCLCs. In conclusion, the absence of the target did not block the development of treatments able to hit LKB1-mutated NSCLCs acting on several fronts. This will give patients a concrete chance to finally benefit from an effective therapy.
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Affiliation(s)
- Gloriana Ndembe
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Ilenia Intini
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Elisa Perin
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Mirko Marabese
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Elisa Caiola
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Paolo Mendogni
- Thoracic Surgery and Lung Transplantation Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Lorenzo Rosso
- Thoracic Surgery and Lung Transplantation Unit, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.,Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Massimo Broggini
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Marika Colombo
- Laboratory of Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
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10
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Bourouh M, Marignani PA. The Tumor Suppressor Kinase LKB1: Metabolic Nexus. Front Cell Dev Biol 2022; 10:881297. [PMID: 35573694 PMCID: PMC9097215 DOI: 10.3389/fcell.2022.881297] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 04/07/2022] [Indexed: 11/13/2022] Open
Abstract
Liver kinase B1 (LKB1) is a multitasking tumor suppressor kinase that is implicated in multiple malignancies such as lung, gastrointestinal, pancreatic, and breast. LKB1 was first identified as the gene responsible for Peutz-Jeghers syndrome (PJS) characterized by hamartomatous polyps and oral mucotaneous pigmentation. LKB1 functions to activate AMP-activated protein kinase (AMPK) during energy stress to shift metabolic processes from active anabolic pathways to active catabolic pathways to generate ATP. Genetic loss or inactivation of LKB1 promotes metabolic reprogramming and metabolic adaptations of cancer cells that fuel increased growth and division rates. As a result, LKB1 loss is associated with increased aggressiveness and treatment options for patients with LKB1 mutant tumors are limited. Recently, there has been new insights into the role LKB1 has on metabolic regulation and the identification of potential vulnerabilities in LKB1 mutant tumors. In this review, we discuss the tumor suppressive role of LKB1 and the impact LKB1 loss has on metabolic reprograming in cancer cells, with a focus on lung cancer. We also discuss potential therapeutic avenues to treat malignancies associated with LKB1 loss by targeting aberrant metabolic pathways associated with LKB1 loss.
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Affiliation(s)
- Mohammed Bourouh
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University Halifax, Halifax, NS, Canada
| | - Paola A Marignani
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University Halifax, Halifax, NS, Canada
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11
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Wilson C, Moyano AL, Cáceres A. Perspectives on Mechanisms Supporting Neuronal Polarity From Small Animals to Humans. Front Cell Dev Biol 2022; 10:878142. [PMID: 35517494 PMCID: PMC9062071 DOI: 10.3389/fcell.2022.878142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 04/04/2022] [Indexed: 11/23/2022] Open
Abstract
Axon-dendrite formation is a crucial milestone in the life history of neurons. During this process, historically referred as “the establishment of polarity,” newborn neurons undergo biochemical, morphological and functional transformations to generate the axonal and dendritic domains, which are the basis of neuronal wiring and connectivity. Since the implementation of primary cultures of rat hippocampal neurons by Gary Banker and Max Cowan in 1977, the community of neurobiologists has made significant achievements in decoding signals that trigger axo-dendritic specification. External and internal cues able to switch on/off signaling pathways controlling gene expression, protein stability, the assembly of the polarity complex (i.e., PAR3-PAR6-aPKC), cytoskeleton remodeling and vesicle trafficking contribute to shape the morphology of neurons. Currently, the culture of hippocampal neurons coexists with alternative model systems to study neuronal polarization in several species, from single-cell to whole-organisms. For instance, in vivo approaches using C. elegans and D. melanogaster, as well as in situ imaging in rodents, have refined our knowledge by incorporating new variables in the polarity equation, such as the influence of the tissue, glia-neuron interactions and three-dimensional development. Nowadays, we have the unique opportunity of studying neurons differentiated from human induced pluripotent stem cells (hiPSCs), and test hypotheses previously originated in small animals and propose new ones perhaps specific for humans. Thus, this article will attempt to review critical mechanisms controlling polarization compiled over decades, highlighting points to be considered in new experimental systems, such as hiPSC neurons and human brain organoids.
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12
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Marquardt J, Chen X, Bi E. Septin Assembly and Remodeling at the Cell Division Site During the Cell Cycle. Front Cell Dev Biol 2021; 9:793920. [PMID: 34901034 PMCID: PMC8656427 DOI: 10.3389/fcell.2021.793920] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/08/2021] [Indexed: 11/17/2022] Open
Abstract
The septin family of proteins can assemble into filaments that further organize into different higher order structures to perform a variety of different functions in different cell types and organisms. In the budding yeast Saccharomyces cerevisiae, the septins localize to the presumptive bud site as a cortical ring prior to bud emergence, expand into an hourglass at the bud neck (cell division site) during bud growth, and finally “split” into a double ring sandwiching the cell division machinery during cytokinesis. While much work has been done to understand the functions and molecular makeups of these structures, the mechanisms underlying the transitions from one structure to another have largely remained elusive. Recent studies involving advanced imaging and in vitro reconstitution have begun to reveal the vast complexity involved in the regulation of these structural transitions, which defines the focus of discussion in this mini-review.
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Affiliation(s)
- Joseph Marquardt
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Xi Chen
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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Albarqi MMY, Ryder SP. The endogenous mex-3 3´UTR is required for germline repression and contributes to optimal fecundity in C. elegans. PLoS Genet 2021; 17:e1009775. [PMID: 34424904 PMCID: PMC8412283 DOI: 10.1371/journal.pgen.1009775] [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: 01/20/2021] [Revised: 09/02/2021] [Accepted: 08/11/2021] [Indexed: 11/18/2022] Open
Abstract
RNA regulation is essential to successful reproduction. Messenger RNAs delivered from parent to progeny govern early embryonic development. RNA-binding proteins (RBPs) are the key effectors of this process, regulating the translation and stability of parental transcripts to control cell fate specification events prior to zygotic gene activation. The KH-domain RBP MEX-3 is conserved from nematode to human. It was first discovered in Caenorhabditis elegans, where it is essential for anterior cell fate and embryo viability. Here, we show that loss of the endogenous mex-3 3´UTR disrupts its germline expression pattern. An allelic series of 3´UTR deletion variants identify repressing regions of the UTR and demonstrate that repression is not precisely coupled to reproductive success. We also show that several RBPs regulate mex-3 mRNA through its 3´UTR to define its unique germline spatiotemporal expression pattern. Additionally, we find that both poly(A) tail length control and the translation initiation factor IFE-3 contribute to its expression pattern. Together, our results establish the importance of the mex-3 3´UTR to reproductive health and its expression in the germline. Our results suggest that additional mechanisms control MEX-3 function when 3´UTR regulation is compromised. In sexually reproducing organisms, germ cells undergo meiosis and differentiate to form oocytes or sperm. Coordination of this process requires a gene regulatory program that acts while the genome is undergoing chromatin condensation. As such, RNA regulatory pathways are an important contributor. The germline of the nematode Caenorhabditis elegans is a suitable model system to study germ cell differentiation. Several RNA-binding proteins (RBPs) coordinate each transition in the germline such as the transition from mitosis to meiosis. MEX-3 is a conserved RNA-binding protein found in most animals including humans. In C. elegans, MEX-3 displays a highly restricted pattern of expression. Here, we define the importance of the 3´UTR in regulating MEX-3 expression pattern in vivo and characterize the RNA-binding proteins involved in this regulation. Our results show that deleting various mex-3 3´UTR regions alter the pattern of expression in the germline in various ways. These mutations also reduced—but did not eliminate—reproductive capacity. Finally, we demonstrate that multiple post-transcriptional mechanisms control MEX-3 levels in different domains of the germline. Our data suggest that coordination of MEX-3 activity requires multiple layers of regulation to ensure reproductive robustness.
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Affiliation(s)
- Mennatallah M. Y. Albarqi
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Sean P. Ryder
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
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14
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Robles P, Turner A, Zuco G, Adams S, Paganopolou P, Winton M, Hill B, Kache V, Bateson C, Pires-daSilva A. Parental energy-sensing pathways control intergenerational offspring sex determination in the nematode Auanema freiburgensis. BMC Biol 2021; 19:102. [PMID: 34001117 PMCID: PMC8130380 DOI: 10.1186/s12915-021-01032-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 04/20/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Environmental stimuli experienced by the parental generation influence the phenotype of subsequent generations (Demoinet et al., Proc Natl Acad Sci U S A 114:E2689-E2698, 2017; Burton et al., Nat Cell Biol 19:252-257, 2017; Agrawal et al., Nature 401:60-63, 1999). The effects of these stimuli on the parental generation may be passed through the germline, but the mechanisms at the basis of this non-Mendelian type of inheritance, their level of conservation, how they lead to adaptive vs non-adaptive, and intergenerational vs transgenerational inheritance are poorly understood. Here we show that modulation of nutrient-sensing pathways in the parental generation of the nematode Auanema freiburgensis regulates phenotypic plasticity of its offspring. RESULTS In response to con-specific pheromones indicative of stress, AMP-activated protein kinase (AMPK), mechanistic target of rapamycin complex 1 (mTORC1), and insulin signaling regulate stress resistance and sex determination across one generation, and these effects can be mimicked by pathway modulators. The effectors of these pathways are closely associated with the chromatin, and their regulation affects the chromatin acetylation status in the germline. CONCLUSION These results suggest that highly conserved metabolic sensors regulate phenotypic plasticity through regulation of subcellular localization of their effectors, leading to changes in chromatin acetylation and epigenetic status of the germline.
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Affiliation(s)
- Pedro Robles
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Anisa Turner
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Giusy Zuco
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Sally Adams
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | | | - Michael Winton
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Beth Hill
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Vikas Kache
- Department of Biology, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Christine Bateson
- Department of Biology, University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Andre Pires-daSilva
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
- Department of Biology, University of Texas at Arlington, Arlington, TX, 76019, USA.
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15
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STK11 gene analysis reveals a significant number of splice mutations in Chinese PJS patients. Cancer Genet 2018; 230:47-57. [PMID: 30528796 DOI: 10.1016/j.cancergen.2018.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/02/2018] [Accepted: 11/27/2018] [Indexed: 01/30/2023]
Abstract
BACKGROUND The combination of direct sequencing and multiple ligation-dependent probe amplification (MLPA) has resulted in an 80% detection rate of serine/threonine kinase 11 (STK11) gene mutations in Peutz-Jeghers syndrome (PJS); however, this rate varies in different ethnicities. AIMS To test the efficacy of the combination in Chinese patients with PJS. METHODS PJS probands visiting our center during one year were enrolled. Sanger sequencing and MLPA were used to detect STK11 mutations. Associations between the occurrence of severe complications and risk factors were analyzed statistically. RESULTS We identified 47 PJS probands. Among them, 34 received an STK11 mutation test, revealing 23 point mutations and 2 exonic deletions. Nine of the mutations were splicing errors, reflecting a significantly higher proportion (p < 0.05). Laparotomy history existed for 33 of the probands, and seven families had a history of cancer. Statistical analysis revealed no associations between the occurrence of severe complications or cancers and risk factors. CONCLUSION The strategy achieved a high detection rate in Chinese people, validating its effectiveness. This cohort comprised a significantly higher proportion of splicing errors, reflecting the unique genetic characteristics Chinese people. No specific genotype-phenotype relationship was noted, while the wide usage of enteroscopy would benefit PJS surveillance.
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16
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Kuwako KI, Okano H. Versatile Roles of LKB1 Kinase Signaling in Neural Development and Homeostasis. Front Mol Neurosci 2018; 11:354. [PMID: 30333724 PMCID: PMC6176002 DOI: 10.3389/fnmol.2018.00354] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/11/2018] [Indexed: 01/01/2023] Open
Abstract
Kinase signaling pathways orchestrate a majority of cellular structures and functions across species. Liver kinase B1 (LKB1, also known as STK11 or Par-4) is a ubiquitously expressed master serine/threonine kinase that plays crucial roles in numerous cellular events, such as polarity control, proliferation, differentiation and energy homeostasis, in many types of cells by activating downstream kinases of the AMP-activated protein kinase (AMPK) subfamily members. In contrast to the accumulating evidence for LKB1 functions in nonneuronal tissues, its functions in the nervous system have been relatively less understood until recently. In the brain, LKB1 initially emerged as a principal regulator of axon/dendrite polarity in forebrain neurons. Thereafter, recent investigations have rapidly uncovered diverse and essential functions of LKB1 in the developing and mature nervous system, such as migration, neurite morphogenesis, myelination and the maintenance of neural integrity, demonstrating that LKB1 is also a multifunctional master kinase in the nervous system. In this review article, we summarize the expanding knowledge about the functional aspects of LKB1 signaling in neural development and homeostasis.
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Affiliation(s)
- Ken-Ichiro Kuwako
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
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17
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Jiang YL, Zhao ZY, Li BR, Yang F, Li J, Jin XW, Wang H, Yu ED, Sun SH, Ning SB. The altered activity of P53 signaling pathway by STK11 gene mutations and its cancer phenotype in Peutz-Jeghers syndrome. BMC MEDICAL GENETICS 2018; 19:141. [PMID: 30092773 PMCID: PMC6085611 DOI: 10.1186/s12881-018-0626-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 06/13/2018] [Indexed: 02/07/2023]
Abstract
Background Peutz-Jeghers syndrome (PJS) is caused by mutations in serine/threonine kinase 11 (STK11) gene. The increased cancer risk has been connected to P53 pathway. Methods PJS probands with STK11 mutation were included in the function analysis. P53 activity elevated by STK11 mutants was investigated using dual-luciferase reporter assay in vitro after constructing expression vectors of STK11 wild type and mutants generated by site-directed substitution. The association between the P53 activity and clinicopathological factors was analysis, especially the cancer history. Results Thirteen probands with STK11 mutations were involved, and within the mutations, c.G924A was novel. P53 activity elevation caused by 6 truncating mutations were significantly lower than that of STK11 wild type (P < 0.05). Family history of cancer was observed in 5 families. Within them, P53 activity was reduced and cancer occurred before 40 in 2 families, while it was not significantly changed and cancers happened after 45 in the other 3 families. Conclusions The affected P53 activity caused by STK11 mutations in PJS patients is significantly associated with protein truncation, while cancer risk in PJS can be elevated through pathways rather than P53 pathway. P53 activity test is probably a useful supporting method to predict cancer risk in PJS, which could be helpful in clinical practice. Electronic supplementary material The online version of this article (10.1186/s12881-018-0626-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yu-Liang Jiang
- Hebei North University, Zhangjiakou, 075061, Hebei Province, China.,Department of Gastroenterology, Airforce General Hospital of PLA, Beijing, 100142, China
| | - Zi-Ye Zhao
- Department of Medical Genetics, Naval Medical University, Shanghai, 200433, China.,Department of Colorectal Surgery, Changhai Hospital, Shanghai, 200433, China
| | - Bai-Rong Li
- Department of Gastroenterology, Airforce General Hospital of PLA, Beijing, 100142, China
| | - Fu Yang
- Department of Medical Genetics, Naval Medical University, Shanghai, 200433, China
| | - Jing Li
- Department of Gastroenterology, Airforce General Hospital of PLA, Beijing, 100142, China
| | - Xiao-Wei Jin
- Department of Gastroenterology, Airforce General Hospital of PLA, Beijing, 100142, China
| | - Hao Wang
- Department of Colorectal Surgery, Changhai Hospital, Shanghai, 200433, China
| | - En-Da Yu
- Department of Colorectal Surgery, Changhai Hospital, Shanghai, 200433, China
| | - Shu-Han Sun
- Department of Medical Genetics, Naval Medical University, Shanghai, 200433, China.
| | - Shou-Bin Ning
- Department of Gastroenterology, Airforce General Hospital of PLA, Beijing, 100142, China.
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18
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Apodaca G. Role of Polarity Proteins in the Generation and Organization of Apical Surface Protrusions. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a027813. [PMID: 28264821 DOI: 10.1101/cshperspect.a027813] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Protruding from the apical surfaces of epithelial cells are specialized structures, including cilia, microplicae, microvilli, and stereocilia. These contribute to epithelial function by cushioning the apical surface, by amplifying its surface area to facilitate nutrient absorption, and by promoting sensory transduction and barrier function. Despite these important roles, and the diseases that result when their formation is perturbed, there remain significant gaps in our understanding of the biogenesis of apical protrusions, or the pathways that promote their organization and orientation once at the apical surface. Here, I review some general aspects of these apical structures, and then discuss our current understanding of their formation and organization with respect to proteins that specify apicobasolateral polarity and planar cell polarity.
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Affiliation(s)
- Gerard Apodaca
- Department of Medicine Renal-Electrolyte Division and the Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
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19
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Pathology and genetics of hereditary colorectal cancer. Pathology 2018; 50:49-59. [DOI: 10.1016/j.pathol.2017.09.004] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 09/11/2017] [Indexed: 12/15/2022]
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20
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Sandí MJ, Marshall CB, Balan M, Coyaud É, Zhou M, Monson DM, Ishiyama N, Chandrakumar AA, La Rose J, Couzens AL, Gingras AC, Raught B, Xu W, Ikura M, Morrison DK, Rottapel R. MARK3-mediated phosphorylation of ARHGEF2 couples microtubules to the actin cytoskeleton to establish cell polarity. Sci Signal 2017; 10:10/503/eaan3286. [PMID: 29089450 DOI: 10.1126/scisignal.aan3286] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The PAR-1-MARK pathway controls cell polarity through the phosphorylation of microtubule-associated proteins. Rho-Rac guanine nucleotide exchange factor 2 (ARHGEF2), which activates Ras homolog family member A (RHOA), is anchored to the microtubule network and sequestered in an inhibited state through binding to dynein light chain Tctex-1 type 1 (DYNLT1). We showed in mammalian cells that liver kinase B1 (LKB1) activated the microtubule affinity-regulating kinase 3 (MARK3), which in turn phosphorylated ARHGEF2 at Ser151 This modification disrupted the interaction between ARHGEF2 and DYNLT1 by generating a 14-3-3 binding site in ARHGEF2, thus causing ARHGEF2 to dissociate from microtubules. Phosphorylation of ARHGEF2 by MARK3 stimulated RHOA activation and the formation of stress fibers and focal adhesions, and was required for organized cellular architecture in three-dimensional culture. Protein phosphatase 2A (PP2A) dephosphorylated Ser151 in ARHGEF2 to restore the inhibited state. Thus, we have identified a regulatory switch controlled by MARK3 that couples microtubules to the actin cytoskeleton to establish epithelial cell polarity through ARHGEF2.
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Affiliation(s)
- María-José Sandí
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada
| | - Christopher B Marshall
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada
| | - Marc Balan
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Étienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada
| | - Ming Zhou
- Center for Cancer Research, National Cancer Institute at Frederick, P.O. Box B, Frederick, MD 21702, USA
| | - Daniel M Monson
- Center for Cancer Research, National Cancer Institute at Frederick, P.O. Box B, Frederick, MD 21702, USA
| | - Noboru Ishiyama
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada
| | - Arun A Chandrakumar
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - José La Rose
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada
| | - Amber L Couzens
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Wei Xu
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada.,Department of Biostatistics, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada.,Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Deborah K Morrison
- Center for Cancer Research, National Cancer Institute at Frederick, P.O. Box B, Frederick, MD 21702, USA
| | - Robert Rottapel
- Princess Margaret Cancer Centre, University Health Network, 101 College Street, Princess Margaret Cancer Research Tower, Toronto, Ontario M5G 1L7, Canada. .,Department of Medical Biophysics, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.,Department of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Department of Immunology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.,Division of Rheumatology, St. Michael's Hospital, 30 Bond Street, Toronto, Ontario M5B 1W8, Canada
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21
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Shashikanth N, Yeruva S, Ong MLDM, Odenwald MA, Pavlyuk R, Turner JR. Epithelial Organization: The Gut and Beyond. Compr Physiol 2017; 7:1497-1518. [DOI: 10.1002/cphy.c170003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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22
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LKB1 as a Tumor Suppressor in Uterine Cancer: Mouse Models and Translational Studies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 943:211-241. [PMID: 27910069 DOI: 10.1007/978-3-319-43139-0_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The LKB1 tumor suppressor was identified in 1998 as the gene mutated in the Peutz-Jeghers Syndrome (PJS), a hereditary cancer predisposition characterized by gastrointestinal polyposis and a high incidence of cancers, particularly carcinomas, at a variety of anatomic sites including the gastrointestinal tract, lung, and female reproductive tract. Women with PJS have a high incidence of carcinomas of the uterine corpus (endometrium) and cervix. The LKB1 gene is also somatically mutated in human cancers arising at these sites. Work in mouse models has highlighted the potency of LKB1 as an endometrial tumor suppressor and its distinctive roles in driving invasive and metastatic growth. These in vivo models represent tractable experimental systems for the discovery of underlying biological principles and molecular processes regulated by LKB1 in the context of tumorigenesis and also serve as useful preclinical model systems for experimental therapeutics. Here we review LKB1's known roles in mTOR signaling, metabolism, and cell polarity, with an emphasis on human pathology and mouse models relevant to uterine carcinogenesis, including cancers of the uterine corpus and cervix.
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23
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Membrane-binding and activation of LKB1 by phosphatidic acid is essential for development and tumour suppression. Nat Commun 2017. [PMID: 28649994 PMCID: PMC5490199 DOI: 10.1038/ncomms15747] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The serine/threonine kinase LKB1 regulates various cellular processes such as cell proliferation, energy homeostasis and cell polarity and is frequently downregulated in various tumours. Many downstream pathways controlled by LKB1 have been described but little is known about the upstream regulatory mechanisms. Here we show that targeting of the kinase to the membrane by a direct binding of LKB1 to phosphatidic acid is essential to fully activate its kinase activity. Consequently, LKB1 mutants that are deficient for membrane binding fail to activate the downstream target AMPK to control mTOR signalling. Furthermore, the in vivo function of LKB1 during development of Drosophila depends on its capacity to associate with membranes. Strikingly, we find LKB1 to be downregulated in malignant melanoma, which exhibit aberrant activation of Akt and overexpress phosphatidic acid generating Phospholipase D. These results provide evidence for a fundamental mechanism of LKB1 activation and its implication in vivo and during carcinogenesis. LKB1 regulates various cellular processes such as cell proliferation, energy homeostasis and cell polarity and is frequently downregulated in various tumours. Here the authors show that LKB1 activation requires direct binding to phospholipids and show this has an implication for carcinogenesis.
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24
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Jia C, Medina V, Liu C, He L, Qian D, Taojian T, Okamoto CT, Stiles BL. Crosstalk of LKB1- and PTEN-regulated signals in liver morphogenesis and tumor development. Hepatol Commun 2017; 1:153-167. [PMID: 29152604 PMCID: PMC5687583 DOI: 10.1002/hep4.1027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Liver kinase B 1 (LKB1 or STK11) and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) are two tumor suppressors that regulate the mammalian target of rapamycin signaling pathway. Deletion studies show that loss of either Lkb1 (Lkb+/–) or Pten (PtenloxP/loxP; Alb‐Cre+) leads to liver injury and development of hepatocarcinoma. In this study, we investigated the crosstalk of LKB1 and PTEN loss during tumorigenesis and liver development. We show that haplo‐insufficiency of Lkb1 in the liver leads to advanced tumor development in Pten‐null mice (PtenloxP/loxP; LkbloxP/+; Alb‐Cre+). Our analysis shows that LKB1 and PTEN interact with each other in their regulation of fatty acid synthase as well as p21 expression. The combined loss of LKB1 and PTEN (PtenloxP/loxP; LkbloxP/loxP; Alb‐Cre+) also leads to the inability to form zonal structures in the liver. The lack of metabolic zonal structures is consistent with the inability of the livers to store glycogen as well as elevated plasma bilirubin and alanine aminotransferase, indicative of liver dysfunction. These structural and functional defects are associated with cytoplasm distribution of a canalicular membrane protein multidrug resistant protein 2, which is responsible for clearing bilirubin. This observed regulation of multidrug resistant protein 2 by LKB1 likely contributes to the lack of cellular polarity and the early lethality phenotype associated with the homozygous loss of Lkb1 alone or in combination with Pten. Finally, Pten deletion does not rescue the precocious ductal plate formation reported for Lkb1‐deleted livers. Conclusion: Our study dissected the functional and molecular crosstalk of PTEN and LKB1 and elucidated key molecular targets for such interactions. (Hepatology Communications 2017;1:153‐167)
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Affiliation(s)
- Chengyou Jia
- Department of Nuclear Medicine, Central Laboratory for Medical Research, Shanghai 10th People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.,Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033
| | - Vivian Medina
- Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033
| | - Chenchang Liu
- Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033
| | - Lina He
- Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033
| | - Daohai Qian
- Department of Nuclear Medicine, Central Laboratory for Medical Research, Shanghai 10th People's Hospital, Tongji University School of Medicine, Shanghai 200072, China.,Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033
| | - Tu Taojian
- Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033
| | - Curtis T Okamoto
- Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033
| | - Bangyan L Stiles
- Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, CA 90033.,Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033
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25
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Narbonne P, Maddox PS, Labbé JC. DAF-18/PTEN signals through AAK-1/AMPK to inhibit MPK-1/MAPK in feedback control of germline stem cell proliferation. PLoS Genet 2017; 13:e1006738. [PMID: 28410423 PMCID: PMC5409174 DOI: 10.1371/journal.pgen.1006738] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 04/28/2017] [Accepted: 04/05/2017] [Indexed: 11/19/2022] Open
Abstract
Under replete growth conditions, abundant nutrient uptake leads to the systemic activation of insulin/IGF-1 signalling (IIS) and the promotion of stem cell growth/proliferation. Activated IIS can stimulate the ERK/MAPK pathway, the activation of which also supports optimal stem cell proliferation in various systems. Stem cell proliferation rates can further be locally refined to meet the resident tissue's need for differentiated progeny. We have recently shown that the accumulation of mature oocytes in the C. elegans germ line, through DAF-18/PTEN, inhibits adult germline stem cell (GSC) proliferation, despite high systemic IIS activation. We show here that this feedback occurs through a novel cryptic signalling pathway that requires PAR-4/LKB1, AAK-1/AMPK and PAR-5/14-3-3 to inhibit the activity of MPK-1/MAPK, antagonize IIS, and inhibit both GSC proliferation and the production of additional oocytes. Interestingly, our results imply that DAF-18/PTEN, through PAR-4/LKB1, can activate AAK-1/AMPK in the absence of apparent energy stress. As all components are conserved, similar signalling cascades may regulate stem cell activities in other organisms and be widely implicated in cancer.
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Affiliation(s)
- Patrick Narbonne
- Department of Pathology and Cell Biology, Institut de Recherche en Immunologie et en Cancérologie (IRIC), Université de Montréal, Montréal, Québec, Canada
| | - Paul S. Maddox
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, United States of America
| | - Jean-Claude Labbé
- Department of Pathology and Cell Biology, Institut de Recherche en Immunologie et en Cancérologie (IRIC), Université de Montréal, Montréal, Québec, Canada
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26
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Suarato G, Lee SI, Li W, Rao S, Khan T, Meng Y, Shelly M. Micellar nanocomplexes for biomagnetic delivery of intracellular proteins to dictate axon formation during neuronal development. Biomaterials 2017; 112:176-191. [PMID: 27768972 PMCID: PMC5121005 DOI: 10.1016/j.biomaterials.2016.09.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 09/10/2016] [Accepted: 09/26/2016] [Indexed: 12/31/2022]
Abstract
During mammalian embryonic development, neurons polarize to create distinct cellular compartments of axon and dendrite that inherently differ in form and function, providing the foundation for directional signaling in the nervous system. Polarization results from spatio-temporal segregation of specific proteins' activities to discrete regions of the neuron to dictate axonal vs. dendritic fate. We aim to manipulate axon formation by directed subcellular localization of crucial intracellular protein function. Here we report critical steps toward the development of a nanotechnology for localized subcellular introduction and retention of an intracellular kinase, LKB1, crucial regulator of axon formation. This nanotechnology will spatially manipulate LKB1-linked biomagnetic nanocomplexes (LKB1-NCs) in developing rodent neurons in culture and in vivo. We created a supramolecular assembly for LKB1 rapid neuronal uptake and prolonged cytoplasmic stability. LKB1-NCs retained kinase activity and phosphorylated downstream targets. NCs were successfully delivered to cultured embryonic hippocampal neurons, and were stable in the cytoplasm for 2 days, sufficient time for axon formation. Importantly, LKB1-NCs promoted axon formation in these neurons, representing unique proof of concept for the sufficiency of intracellular protein function in dictating a central developmental event. Lastly, we established NC delivery into cortical progenitors in live rat embryonic brain in utero. Our nanotechnology provides a viable platform for spatial manipulation of intracellular protein-activity, to dictate central events during neuronal development.
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Affiliation(s)
- Giulia Suarato
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Seong-Il Lee
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Weiyi Li
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Sneha Rao
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Tanvir Khan
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Yizhi Meng
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, NY, USA
| | - Maya Shelly
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, NY, USA.
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27
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Abstract
PAR-1/MARK kinases are conserved serine/threonine kinases that are essential regulators of cell polarity. PAR-1/MARK kinases localize and function in opposition to the anterior PAR proteins to control the asymmetric distribution of factors in a wide variety polarized cells. In this review, we discuss the mechanisms that control the localization and activity of PAR-1/MARK kinases, including their antagonistic interactions with the anterior PAR proteins. We focus on the role PAR-1 plays in the asymmetric division of the Caenorhabditis elegans zygote, in the establishment of the anterior/posterior axis in the Drosophila oocyte and in the control of microtubule dynamics in mammalian neurons. In addition to conserved aspects of PAR-1 biology, we highlight the unique ways in which PAR-1 acts in these distinct cell types to orchestrate their polarization. Finally, we review the connections between disruptions in PAR-1/MARK function and Alzheimer's disease and cancer.
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Affiliation(s)
- Youjun Wu
- Dartmouth College, Hanover, NH, United States
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28
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Jordan SN, Davies T, Zhuravlev Y, Dumont J, Shirasu-Hiza M, Canman JC. Cortical PAR polarity proteins promote robust cytokinesis during asymmetric cell division. J Cell Biol 2016; 212:39-49. [PMID: 26728855 PMCID: PMC4700484 DOI: 10.1083/jcb.201510063] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In asymmetrically dividing C. elegans embryos, the core cortical PAR proteins are required to retain septin and anillin at the anterior cortex away from the contractile ring and to promote normal F-actin levels at the contractile ring and successful cytokinesis. Cytokinesis, the physical division of one cell into two, is thought to be fundamentally similar in most animal cell divisions and driven by the constriction of a contractile ring positioned and controlled solely by the mitotic spindle. During asymmetric cell divisions, the core polarity machinery (partitioning defective [PAR] proteins) controls the unequal inheritance of key cell fate determinants. Here, we show that in asymmetrically dividing Caenorhabditis elegans embryos, the cortical PAR proteins (including the small guanosine triphosphatase CDC-42) have an active role in regulating recruitment of a critical component of the contractile ring, filamentous actin (F-actin). We found that the cortical PAR proteins are required for the retention of anillin and septin in the anterior pole, which are cytokinesis proteins that our genetic data suggest act as inhibitors of F-actin at the contractile ring. Collectively, our results suggest that the cortical PAR proteins coordinate the establishment of cell polarity with the physical process of cytokinesis during asymmetric cell division to ensure the fidelity of daughter cell formation.
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Affiliation(s)
- Shawn N Jordan
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032
| | - Tim Davies
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032
| | - Yelena Zhuravlev
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032 Department of Genetics and Development, Columbia University, New York, NY 10032
| | - Julien Dumont
- Institut Jacques Monod, Centre National de la Recherche Scientifique, Unites Mixtes de Recherche 7592, Universite Paris Diderot, Sorbonne Paris Cité, 75205 Paris, France
| | - Mimi Shirasu-Hiza
- Department of Genetics and Development, Columbia University, New York, NY 10032
| | - Julie C Canman
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032
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29
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Bonastre E, Brambilla E, Sanchez-Cespedes M. Cell adhesion and polarity in squamous cell carcinoma of the lung. J Pathol 2016; 238:606-16. [PMID: 26749265 DOI: 10.1002/path.4686] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 12/18/2015] [Accepted: 12/30/2015] [Indexed: 01/01/2023]
Abstract
Lung cancer is a deadly disease that can roughly be classified into three histopathological groups: lung adenocarcinomas, lung squamous cell carcinomas (LSCCs), and small cell carcinomas. These types of lung cancer are molecularly, phenotypically, and regionally diverse neoplasms, reflecting differences in their cells of origin. LSCCs commonly arise in the airway epithelium of a main or lobar bronchus, which is an important line of defence against the external environment. Furthermore, most LSCCs are characterized histopathologically by the presence of keratinization and/or intercellular bridges, consistent with the molecular features of these tumours, characterized by high levels of transcripts encoding keratins and proteins relevant to intercellular junctions and cell polarity. In this review, the relationships between the molecular features of LSCCs and the types of cell and epithelia of origin are discussed. Recurrent alterations in genes involved in intercellular adhesion and cell polarity in LSCCs are also reviewed, emphasizing the importance of the disruption of PAR3 and the PAR complex. Finally, the possible functional effects of these alterations on epithelial homeostasis, and how they contribute to the development of LSCC, are discussed.
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Affiliation(s)
- Ester Bonastre
- Genes and Cancer Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, Spain
| | - Elisabeth Brambilla
- Department of Pathology, Institut Albert Bonniot, INSERM U823, University Joseph Fourier, CHU, Grenoble Hopital Michallon, Grenoble, France
| | - Montse Sanchez-Cespedes
- Genes and Cancer Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, Spain
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30
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Konen J, Wilkinson S, Lee B, Fu H, Zhou W, Jiang Y, Marcus AI. LKB1 kinase-dependent and -independent defects disrupt polarity and adhesion signaling to drive collagen remodeling during invasion. Mol Biol Cell 2016; 27:1069-84. [PMID: 26864623 PMCID: PMC4814216 DOI: 10.1091/mbc.e15-08-0569] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 02/05/2016] [Indexed: 12/23/2022] Open
Abstract
LKB1 is a serine/threonine kinase and a commonly mutated gene in lung adenocarcinoma. The majority of LKB1 mutations are truncations that disrupt its kinase activity and remove its C-terminal domain (CTD). Because LKB1 inactivation drives cancer metastasis in mice and leads to aberrant cell invasion in vitro, we sought to determine how compromised LKB1 function affects lung cancer cell polarity and invasion. Using three-dimensional models, we show that LKB1 kinase activity is essential for focal adhesion kinase-mediated cell adhesion and subsequent collagen remodeling but not cell polarity. Instead, cell polarity is overseen by the kinase-independent function of its CTD and more specifically its farnesylation. This occurs through a mesenchymal-amoeboid morphological switch that signals through the Rho-GTPase RhoA. These data suggest that a combination of kinase-dependent and -independent defects by LKB1 inactivation creates a uniquely invasive cell with aberrant polarity and adhesion signaling that drives invasion into the microenvironment.
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Affiliation(s)
- Jessica Konen
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA 30322 Graduate Program in Cancer Biology, Emory University, Atlanta, GA 30322
| | - Scott Wilkinson
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA 30322 Graduate Program in Cancer Biology, Emory University, Atlanta, GA 30322
| | - Byoungkoo Lee
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA 30302
| | - Haian Fu
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA 30322 Department of Pharmacology, Emory University, Atlanta, GA 30322
| | - Wei Zhou
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA 30322
| | - Yi Jiang
- Department of Mathematics and Statistics, Georgia State University, Atlanta, GA 30302
| | - Adam I Marcus
- Department of Hematology and Medical Oncology, Winship Cancer Institute of Emory University, Atlanta, GA 30322
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31
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Pacquelet A, Uhart P, Tassan JP, Michaux G. PAR-4 and anillin regulate myosin to coordinate spindle and furrow position during asymmetric division. J Cell Biol 2015; 210:1085-99. [PMID: 26416962 PMCID: PMC4586735 DOI: 10.1083/jcb.201503006] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
During asymmetric cell division, the mitotic spindle and polarized myosin can both determine the position of the cytokinetic furrow. However, how cells coordinate signals from the spindle and myosin to ensure that cleavage occurs through the spindle midzone is unknown. Here, we identify a novel pathway that is essential to inhibit myosin and coordinate furrow and spindle positions during asymmetric division. In Caenorhabditis elegans one-cell embryos, myosin localizes at the anterior cortex whereas the mitotic spindle localizes toward the posterior. We find that PAR-4/LKB1 impinges on myosin via two pathways, an anillin-dependent pathway that also responds to the cullin CUL-5 and an anillin-independent pathway involving the kinase PIG-1/MELK. In the absence of both PIG-1/MELK and the anillin ANI-1, myosin accumulates at the anterior cortex and induces a strong displacement of the furrow toward the anterior, which can lead to DNA segregation defects. Regulation of asymmetrically localized myosin is thus critical to ensure that furrow and spindle midzone positions coincide throughout cytokinesis.
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Affiliation(s)
- Anne Pacquelet
- Centre National de la Recherche Scientifique, UMR6290, Rennes, France Université de Rennes 1, Institut de Génétique et Développement de Rennes, 35043 Rennes, France
| | - Perrine Uhart
- Centre National de la Recherche Scientifique, UMR6290, Rennes, France Université de Rennes 1, Institut de Génétique et Développement de Rennes, 35043 Rennes, France
| | - Jean-Pierre Tassan
- Centre National de la Recherche Scientifique, UMR6290, Rennes, France Université de Rennes 1, Institut de Génétique et Développement de Rennes, 35043 Rennes, France
| | - Grégoire Michaux
- Centre National de la Recherche Scientifique, UMR6290, Rennes, France Université de Rennes 1, Institut de Génétique et Développement de Rennes, 35043 Rennes, France
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32
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Ajduk A, Zernicka-Goetz M. Polarity and cell division orientation in the cleavage embryo: from worm to human. Mol Hum Reprod 2015; 22:691-703. [PMID: 26660321 PMCID: PMC5062000 DOI: 10.1093/molehr/gav068] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/25/2015] [Indexed: 01/01/2023] Open
Abstract
Cleavage is a period after fertilization, when a 1-cell embryo starts developing into a multicellular organism. Due to a series of mitotic divisions, the large volume of a fertilized egg is divided into numerous smaller, nucleated cells—blastomeres. Embryos of different phyla divide according to different patterns, but molecular mechanism of these early divisions remains surprisingly conserved. In the present paper, we describe how polarity cues, cytoskeleton and cell-to-cell communication interact with each other to regulate orientation of the early embryonic division planes in model animals such as Caenorhabditis elegans, Drosophila and mouse. We focus particularly on the Par pathway and the actin-driven cytoplasmic flows that accompany it. We also describe a unique interplay between Par proteins and the Hippo pathway in cleavage mammalian embryos. Moreover, we discuss the potential meaning of polarity, cytoplasmic dynamics and cell-to-cell communication as quality biomarkers of human embryos.
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Affiliation(s)
- Anna Ajduk
- Department of Embryology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
| | - Magdalena Zernicka-Goetz
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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33
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Moorhouse KS, Gudejko HF, McDougall A, Burgess DR. Influence of cell polarity on early development of the sea urchin embryo. Dev Dyn 2015; 244:1469-84. [PMID: 26293695 PMCID: PMC4715636 DOI: 10.1002/dvdy.24337] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 08/11/2015] [Accepted: 08/13/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Establishment and maintenance of cell polarity is critical for normal embryonic development. Previously, it was thought that the echinoderm embryo remained relatively unpolarized until the first asymmetric division at the 16-cell stage. Here, we analyzed roles of the cell polarity regulators, the PAR complex proteins, and how their disruption in early development affects later developmental milestones. RESULTS We found that PAR6, aPKC, and CDC42 localize to the apical cortex as early as the 2-cell stage and that this localization is retained through the gastrula stage. Of interest, PAR1 also colocalizes with these apical markers through the gastrula stage. Additionally, PAR1 was found to be in complex with aPKC, but not PAR6. PAR6, aPKC, and CDC42 are anchored in the cortical actin cytoskeleton by assembled myosin. Furthermore, assembled myosin was found to be necessary to maintain proper PAR6 localization through subsequent cleavage divisions. Interference with myosin assembly prevented the embryos from reaching the blastula stage, while transient disruptions of either actin or microtubules did not have this effect. CONCLUSIONS These observations suggest that disruptions of the polarity in the early embryo can have a significant impact on the ability of the embryo to reach later critical stages in development.
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Affiliation(s)
- Kathleen S. Moorhouse
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
| | - Heather F.M. Gudejko
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
| | - Alex McDougall
- UMR 7009, UPMC Sorbonne Universités, Centre National de la Recherche (CNRS), Observatoire Océanologique, 181 Chemin du Lazaret, 06230 Villefranche-sur-Mer, France
| | - David R. Burgess
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
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34
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Seidel HS, Kimble J. Cell-cycle quiescence maintains Caenorhabditis elegans germline stem cells independent of GLP-1/Notch. eLife 2015; 4. [PMID: 26551561 PMCID: PMC4718729 DOI: 10.7554/elife.10832] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 11/07/2015] [Indexed: 12/13/2022] Open
Abstract
Many types of adult stem cells exist in a state of cell-cycle quiescence, yet it has remained unclear whether quiescence plays a role in maintaining the stem cell fate. Here we establish the adult germline of Caenorhabditis elegans as a model for facultative stem cell quiescence. We find that mitotically dividing germ cells--including germline stem cells--become quiescent in the absence of food. This quiescence is characterized by a slowing of S phase, a block to M-phase entry, and the ability to re-enter M phase rapidly in response to re-feeding. Further, we demonstrate that cell-cycle quiescence alters the genetic requirements for stem cell maintenance: The signaling pathway required for stem cell maintenance under fed conditions--GLP-1/Notch signaling--becomes dispensable under conditions of quiescence. Thus, cell-cycle quiescence can itself maintain stem cells, independent of the signaling pathway otherwise essential for such maintenance.
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Affiliation(s)
- Hannah S Seidel
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States.,The Ellison Medical Foundation Fellow of the Life Sciences Research Foundation, The Lawrence Ellison Foundation, Mount Airy, United States
| | - Judith Kimble
- Department of Biochemistry, University of Wisconsin-Madison, Madison, United States.,Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, United States
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35
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Abstract
A fundamental question in developmental biology is how different cell lineages acquire different cell cycle durations. With its highly stereotypical asymmetric and asynchronous cell divisions, the early Caenorhabditis elegans embryo provides an ideal system to study lineage-specific cell cycle timing regulation during development, with high spatio-temporal resolution. The first embryonic division is asymmetric and generates two blastomeres of different sizes (AB>P1) and developmental potentials that divide asynchronously, with the anterior somatic blastomere AB dividing reproducibly two minutes before the posterior germline blastomere P1. The evolutionarily conserved PAR proteins (abnormal embryonic PARtitioning of cytoplasm) regulate all of the asymmetries in the early embryo including cell cycle asynchrony between AB and P1 blastomeres. Here we discuss our current understanding and open questions on the mechanism by which the PAR proteins regulate asynchronous cell divisions in the early C. elegans embryo.
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36
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Promotion of bone morphogenetic protein signaling by tetraspanins and glycosphingolipids. PLoS Genet 2015; 11:e1005221. [PMID: 25978409 PMCID: PMC4433240 DOI: 10.1371/journal.pgen.1005221] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 04/14/2015] [Indexed: 02/08/2023] Open
Abstract
Bone morphogenetic proteins (BMPs) belong to the transforming growth factor β (TGFβ) superfamily of secreted molecules. BMPs play essential roles in multiple developmental and homeostatic processes in metazoans. Malfunction of the BMP pathway can cause a variety of diseases in humans, including cancer, skeletal disorders and cardiovascular diseases. Identification of factors that ensure proper spatiotemporal control of BMP signaling is critical for understanding how this pathway is regulated. We have used a unique and sensitive genetic screen to identify the plasma membrane-localized tetraspanin TSP-21 as a key new factor in the C. elegans BMP-like “Sma/Mab” signaling pathway that controls body size and postembryonic M lineage development. We showed that TSP-21 acts in the signal-receiving cells and genetically functions at the ligand-receptor level. We further showed that TSP-21 can associate with itself and with two additional tetraspanins, TSP-12 and TSP-14, which also promote Sma/Mab signaling. TSP-12 and TSP-14 can also associate with SMA-6, the type I receptor of the Sma/Mab pathway. Finally, we found that glycosphingolipids, major components of the tetraspanin-enriched microdomains, are required for Sma/Mab signaling. Our findings suggest that the tetraspanin-enriched membrane microdomains are important for proper BMP signaling. As tetraspanins have emerged as diagnostic and prognostic markers for tumor progression, and TSP-21, TSP-12 and TSP-14 are all conserved in humans, we speculate that abnormal BMP signaling due to altered expression or function of certain tetraspanins may be a contributing factor to cancer development. The bone morphogenetic protein (BMP) signaling pathway is required for multiple developmental processes during metazoan development. Various diseases, including cancer, can result from mis-regulation of the BMP pathway. Thus, it is critical to identify factors that ensure proper regulation of BMP signaling. Using the nematode C. elegans, we have devised a highly specific and sensitive genetic screen to identify new modulators in the BMP pathway. Through this screen, we identified three conserved tetraspanin molecules as novel factors that function to promote BMP signaling in a living organism. We further showed that these three tetraspanins likely form a complex and function together with glycosphingolipids to promote BMP signaling. Recent studies have implicated several tetraspanins in cancer initiation, progression and metastasis in mammals. Our findings suggest that the involvement of tetraspanins in cancer may partially be due to their function in modulating the activity of BMP signaling.
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37
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Griffin EE. Cytoplasmic localization and asymmetric division in the early embryo of Caenorhabditis elegans. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2015; 4:267-82. [PMID: 25764455 DOI: 10.1002/wdev.177] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 12/16/2014] [Accepted: 01/04/2015] [Indexed: 11/09/2022]
Abstract
During the initial cleavages of the Caenorhabditis elegans embryo, a series of rapid and invariant asymmetric cell divisions pattern the fate, size, and position of four somatic blastomeres and a single germline blastomere. These asymmetric divisions are orchestrated by a collection of maternally deposited factors that are initially symmetrically distributed in the newly fertilized embryo. Maturation of the sperm-derived centrosome in the posterior cytoplasm breaks this symmetry by triggering a dramatic and highly stereotyped partitioning of these maternal factors. A network of conserved cell polarity regulators, the PAR proteins, form distinct anterior and posterior domains at the cell cortex. From these domains, the PAR proteins direct the segregation of somatic and germline factors into opposing regions of the cytoplasm such that, upon cell division, they are preferentially inherited by the somatic blastomere or the germline blastomere, respectively. The segregation of these factors is controlled, at least in part, by a series of reaction-diffusion mechanisms that are asymmetrically deployed along the anterior/posterior axis. The characterization of these mechanisms has important implications for our understanding of how cells are polarized and how spatial organization is generated in the cytoplasm. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Erik E Griffin
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
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38
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Krawchuk D, Anani S, Honma-Yamanaka N, Polito S, Shafik M, Yamanaka Y. Loss of LKB1 leads to impaired epithelial integrity and cell extrusion in the early mouse embryo. J Cell Sci 2015; 128:1011-22. [PMID: 25588837 DOI: 10.1242/jcs.162156] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
LKB1/PAR-4 is essential for the earliest polarization steps in Caenorhabditis elegans embryos and Drosophila oocytes. Although LKB1 (also known as STK11) is sufficient to initiate polarity in a single mammalian intestinal epithelial cell, its necessity in the formation and maintenance of mammalian epithelia remains unclear. To address this, we completely remove LKB1 from mouse embryos by generating maternal-zygotic Lkb1 mutants and find that it is dispensable for polarity and epithelia formation in the early embryo. Instead, loss of Lkb1 leads to the extrusion of cells from blastocyst epithelia that remain alive and can continue to divide. Chimeric analysis shows that Lkb1 is cell-autonomously required to prevent these extrusions. Furthermore, heterozygous loss of Cdh1 exacerbates the number of extrusions per blastocyst, suggesting that LKB1 has a role in regulating adherens junctions in order to prevent extrusion in epithelia.
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Affiliation(s)
- Dayana Krawchuk
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Room 419, Montréal, QC H3A 1A3, Canada
| | - Shihadeh Anani
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Room 419, Montréal, QC H3A 1A3, Canada Department of Human Genetics, McGill University, 1160 Pine Avenue West, Room 419, Montréal, QC H3A 1A3, Canada
| | - Nobuko Honma-Yamanaka
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Room 419, Montréal, QC H3A 1A3, Canada
| | - Samantha Polito
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Room 419, Montréal, QC H3A 1A3, Canada
| | - Marian Shafik
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Room 419, Montréal, QC H3A 1A3, Canada
| | - Yojiro Yamanaka
- Goodman Cancer Research Centre, McGill University, 1160 Pine Avenue West, Room 419, Montréal, QC H3A 1A3, Canada Department of Human Genetics, McGill University, 1160 Pine Avenue West, Room 419, Montréal, QC H3A 1A3, Canada
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39
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Chan KT, Asokan SB, King SJ, Bo T, Dubose ES, Liu W, Berginski ME, Simon JM, Davis IJ, Gomez SM, Sharpless NE, Bear JE. LKB1 loss in melanoma disrupts directional migration toward extracellular matrix cues. ACTA ACUST UNITED AC 2015; 207:299-315. [PMID: 25349262 PMCID: PMC4210439 DOI: 10.1083/jcb.201404067] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The LKB1 kinase regulates directional migration in response to extracellular matrix gradients and may inhibit invasive motility by sensing inhibitory matrix cues. Somatic inactivation of the serine/threonine kinase gene STK11/LKB1/PAR-4 occurs in a variety of cancers, including ∼10% of melanoma. However, how the loss of LKB1 activity facilitates melanoma invasion and metastasis remains poorly understood. In LKB1-null cells derived from an autochthonous murine model of melanoma with activated Kras and Lkb1 loss and matched reconstituted controls, we have investigated the mechanism by which LKB1 loss increases melanoma invasive motility. Using a microfluidic gradient chamber system and time-lapse microscopy, in this paper, we uncover a new function for LKB1 as a directional migration sensor of gradients of extracellular matrix (haptotaxis) but not soluble growth factor cues (chemotaxis). Systematic perturbation of known LKB1 effectors demonstrated that this response does not require canonical adenosine monophosphate–activated protein kinase (AMPK) activity but instead requires the activity of the AMPK-related microtubule affinity-regulating kinase (MARK)/PAR-1 family kinases. Inhibition of the LKB1–MARK pathway facilitated invasive motility, suggesting that loss of the ability to sense inhibitory matrix cues may promote melanoma invasion.
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Affiliation(s)
- Keefe T Chan
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Sreeja B Asokan
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Samantha J King
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Tao Bo
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Evan S Dubose
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Wenjin Liu
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Matthew E Berginski
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Jeremy M Simon
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Ian J Davis
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Shawn M Gomez
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - Norman E Sharpless
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
| | - James E Bear
- University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599 University of North Carolina Lineberger Comprehensive Cancer Center, Department of Cell Biology and Physiology, Department of Genetics, Department of Biomedical Engineering, Carolina Center for Genome Science, Department of Pediatrics, and Howard Hughes Medical Institute, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599
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Huang NN, Hunter CP. The RNA binding protein MEX-3 retains asymmetric activity in the early Caenorhabditis elegans embryo in the absence of asymmetric protein localization. Gene 2014; 554:160-73. [PMID: 25445286 DOI: 10.1016/j.gene.2014.10.042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 10/23/2014] [Accepted: 10/25/2014] [Indexed: 10/24/2022]
Abstract
The RNA binding protein MEX-3 is required to restrict translation of pal-1, the Caenorhabditis elegans caudal homolog, to the posterior of the early embryo. MEX-3 is present uniformly throughout the newly fertilized embryo, but becomes depleted in the posterior by the 4-cell stage. This MEX-3 patterning requires the CCCH zinc-finger protein MEX-5, the RNA Recognition Motif protein SPN-4, and the kinase PAR-4. Genetic and biochemical evidence suggests that MEX-5 binds to MEX-3 in the anterior of the embryo, protecting MEX-3 from degradation and allowing it to bind the pal-1 3'UTR and repress translation. MEX-3 that is not bound to MEX-5 becomes inactivated by par-4, then targeted for spn-4 dependent degradation. After the 4-cell stage, residual MEX-3 is degraded in somatic cells, and only persists in the germline precursors. To better understand regulation of mex-3, GFP was fused to MEX-3 or regions of MEX-3 and expressed in developing oocytes. GFP::MEX-3 expressed in this manner can replace endogenous MEX-3, but surprisingly is not asymmetrically localized at the 4-cell stage. These results indicate that GFP::MEX-3 retains asymmetric activity even in the absence of asymmetric protein localization. Neither the mex-3 3'UTR nor protein degradation at the 4-cell stage is strictly required. A region of MEX-3 containing a glutamine-rich region and potential ubiquitination and phosphorylation sites is sufficient for soma-germline asymmetry. Results from mex-5/6 and spn-4(RNAi) suggest two pathways for MEX-3 degradation, an early spn-4 dependent pathway and a later spn-4 independent pathway. These results indicate that mex-3 activity is regulated at multiple levels, leading to rapid and robust regulation in the quickly developing early embryo.
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Affiliation(s)
- Nancy N Huang
- Molecular Biology Department, Colorado College, Colorado Springs, CO 80903, USA.
| | - Craig P Hunter
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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Abstract
Apico-basal polarity is a cardinal molecular feature of adult eukaryotic epithelial cells and appears to be involved in several key cellular processes including polarized cell migration and maintenance of tissue architecture. Epithelial cell polarity is maintained by three well-conserved polarity complexes, namely, PAR, Crumbs and SCRIB. The location and interaction between the components of these complexes defines distinct structural domains of epithelial cells. Establishment and maintenance of apico-basal polarity is regulated through various conserved cell signalling pathways including TGF beta, Integrin and WNT signalling. Loss of cell polarity is a hallmark for carcinoma, and its underlying molecular mechanism is beginning to emerge from studies on model organisms and cancer cell lines. Moreover, deregulated expression of apico-basal polarity complex components has been reported in human tumours. In this review, we provide an overview of the apico-basal polarity complexes and their regulation, their role in cell migration, and finally their involvement in carcinogenesis.
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Affiliation(s)
- Mohammed Khursheed
- Centre for DNA Fingerprinting and Diagnostics (CDFD), Nampally, Hyderabad 500 001, India
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Recent progress on liver kinase B1 (LKB1): expression, regulation, downstream signaling and cancer suppressive function. Int J Mol Sci 2014; 15:16698-718. [PMID: 25244018 PMCID: PMC4200829 DOI: 10.3390/ijms150916698] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/12/2014] [Accepted: 08/28/2014] [Indexed: 12/15/2022] Open
Abstract
Liver kinase B1 (LKB1), known as a serine/threonine kinase, has been identified as a critical cancer suppressor in many cancer cells. It is a master upstream kinase of 13 AMP-activated protein kinase (AMPK)-related protein kinases, and possesses versatile biological functions. LKB1 gene is mutated in many cancers, and its protein can form different protein complexes with different cellular localizations in various cell types. The expression of LKB1 can be regulated through epigenetic modification, transcriptional regulation and post-translational modification. LKB1 dowcnstream pathways mainly include AMPK, microtubule affinity regulating kinase (MARK), salt-inducible kinase (SIK), sucrose non-fermenting protein-related kinase (SNRK) and brain selective kinase (BRSK) signalings, etc. This review, therefore, mainly discusses recent studies about the expression, regulation, downstream signaling and cancer suppressive function of LKB1, which can be helpful for better understanding of this molecular and its significance in cancers.
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Li J, Liu J, Li P, Mao X, Li W, Yang J, Liu P. Loss of LKB1 disrupts breast epithelial cell polarity and promotes breast cancer metastasis and invasion. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2014; 33:70. [PMID: 25178656 PMCID: PMC4431490 DOI: 10.1186/s13046-014-0070-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 08/18/2014] [Indexed: 12/22/2022]
Abstract
Background LKB1, also known as STK11, is a master kinase that serves as an energy metabolic sensor and is involved in cell polarity regulation. Recent studies have indicated that LKB1 is related to breast tumorigenesis and breast cancer progression. However, little work has been done on the roles of LKB1 in cell polarity and epithelial-mesenchymal transition in breast cancer. In this study, we tried to prove that loss of LKB1 disrupts breast epithelial cell polarity and causes tumor metastasis and invasion. Methods The relationships of LKB1 expression to clinic-pathological parameters and epithelial markers E-cadherin and high-molecular-weight -cytokeratin (HMW-CK) were investigated in 80 clinical breast cancer tissue samples and their paired normal control breast tissue samples by using immunohistochemistry. Then, the LKB1 expressions in metastatic and non-metastatic breast cancer cell lines were compared. The roles of LKB1 in cell polarity and epithelial-mesenchymal transition in breast cancer were determined by using immunofluorescence, western blot assay, and cell migration and invasive assays. Finally, the non-transformed human breast cell line MCF-10A was cultured in three dimensions to further reveal the role of LKB1 in breast epithelial cell polarity maintenance. Results Histopathological analysis showed that LKB1 expression level was significantly negatively correlated with breast cancer TNM stage, and positively correlated with ER/PR status and expression levels of E-cadherin and HMW-CK. Immunofluorescence staining showed that LKB1 was co-localized with E-cadherin at adheren junctions. In vitro analysis revealed that loss of LKB1 expression enhanced migration, invasion and the acquisition of mesenchymal phenotype, while LKB1 overexpression in MDA-MB-435 s cells, which have a low basal level of LKB1 expression, promoted the acquisition of epithelial phenotype. Finally, it was found for the first time that endogenous LKB1 knockdown resulted in abnormal cell polarity in acini formed by non-transformed breast epithelial cells grown in 3D culture. Conclusion Our data indicated that low expression of LKB1 was significantly associated with established markers of unfavorable breast cancer prognosis, such as loss of ER/PR, E-cadherin and HMW-CK. Knockdown of endogenous LKB1 gave rise to dysregulation of cell polarity and invasive phenotype of breast cancer cells.
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Affiliation(s)
- Juan Li
- Center for Translational Medicine, The First Affiliated Hospital, Xian Jiaotong University College of Medicine, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China.
| | - Jie Liu
- Center for Translational Medicine, The First Affiliated Hospital, Xian Jiaotong University College of Medicine, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China.
| | - Pingping Li
- Center for Translational Medicine, The First Affiliated Hospital, Xian Jiaotong University College of Medicine, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China.
| | - Xiaona Mao
- Center for Translational Medicine, The First Affiliated Hospital, Xian Jiaotong University College of Medicine, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China.
| | - Wenjie Li
- Center for Translational Medicine, The First Affiliated Hospital, Xian Jiaotong University College of Medicine, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China.
| | - Jin Yang
- Department of Oncology, The First Affiliated Hospital, Xian Jiaotong University College of Medicine, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China.
| | - Peijun Liu
- Center for Translational Medicine, The First Affiliated Hospital, Xian Jiaotong University College of Medicine, 277 West Yanta Road, Xi'an, Shaanxi, 710061, People's Republic of China.
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Benkemoun L, Descoteaux C, Chartier NT, Pintard L, Labbé JC. PAR-4/LKB1 regulates DNA replication during asynchronous division of the early C. elegans embryo. ACTA ACUST UNITED AC 2014; 205:447-55. [PMID: 24841566 PMCID: PMC4033775 DOI: 10.1083/jcb.201312029] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
DNA replication is asymmetrically regulated in the two-cell stage C. elegans embryo by the PAR-4 and PAR-1 polarity proteins, which function independently of known regulators of cell cycle timing to dampen DNA replication dynamics specifically in the posterior blastomere. Regulation of cell cycle duration is critical during development, yet the underlying molecular mechanisms are still poorly understood. The two-cell stage Caenorhabditis elegans embryo divides asynchronously and thus provides a powerful context in which to study regulation of cell cycle timing during development. Using genetic analysis and high-resolution imaging, we found that deoxyribonucleic acid (DNA) replication is asymmetrically regulated in the two-cell stage embryo and that the PAR-4 and PAR-1 polarity proteins dampen DNA replication dynamics specifically in the posterior blastomere, independently of regulators previously implicated in the control of cell cycle timing. Our results demonstrate that accurate control of DNA replication is crucial during C. elegans early embryonic development and further provide a novel mechanism by which PAR proteins control cell cycle progression during asynchronous cell division.
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Affiliation(s)
- Laura Benkemoun
- Cell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Catherine Descoteaux
- Cell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Nicolas T Chartier
- Cell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Lionel Pintard
- Institut Jacques Monod, Centre National de la Recherche Scientifique and Université Paris Diderot, F-75013 Paris, France
| | - Jean-Claude Labbé
- Cell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, CanadaCell Division and Differentiation Laboratory, Institute of Research in Immunology and Cancer, and Department of Pathology and Cell Biology, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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Liu K, Luo Y, Tian H, Yu KZ, He JX, Shen WY. The tumor suppressor LKB1 antagonizes WNT signaling pathway through modulating GSK3β activity in cell growth of esophageal carcinoma. Tumour Biol 2014; 35:995-1002. [PMID: 24022664 DOI: 10.1007/s13277-013-1133-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 08/23/2013] [Indexed: 01/07/2023] Open
Abstract
The tumor suppressor LKB1 gene encodes a serine-threonine kinase that regulates cell proliferation and polarity. Inactivation of LKB1 by mutations in LKB1 or loss of its expression is highly correlated with lung, ovarian, and pancreatic cancers, and WNT/β-catenin pathway is also known to be involved in many human malignancies. However, the relationship between LKB1 and WNT signaling pathway in esophageal carcinoma remains unknown. The expression of LKB1 in 62 cases of esophageal cancer patients was determined by quantitative real-time PCR. It was found that LKB1 mRNA level was significantly lower than the adjacent normal epithelium and that the LKB1 downregulation was correlating with TNM stages. Moreover, the expression of WNT target genes such as Cyclin D1, C-MYC, MMP2, and FZD2 was significantly upregulated in esophageal cancer tissues. LKB1 overexpression in TE10 cells inhibited TOPFlash luciferase reporter activity and WNT target gene expression even in the presence of WNT3A. Conversely, LKB1 knockdown enhanced WNT signaling activity in esophageal cancer cells. It was also found that LKB1 antagonized WNT signaling pathway through interaction with GSK3β to downregulate β-catenin expression level. Functional investigation revealed that LKB1 suppressed the promotion effects of WNT3A on the cell growth of TE10 cells. The LKB1 functions in regulating cell growth and WNT target genes expression were impaired by GSK3β inhibition, suggesting that LKB1 antagonized WNT-induced cell proliferation through enhancement of GSK3β activity. Together, the interaction between LKB1 and GSK3β upregulates GSK3β activity to suppress WNT-induced cell proliferation in esophageal carcinoma cells. Loss of LKB1 expression may result in the deregulation of WNT/β-catenin pathway to promote malignant progression of esophageal cancer.
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Veleva-Rotse BO, Smart JL, Baas AF, Edmonds B, Zhao ZM, Brown A, Klug LR, Hansen K, Reilly G, Gardner AP, Subbiah K, Gaucher EA, Clevers H, Barnes AP. STRAD pseudokinases regulate axogenesis and LKB1 stability. Neural Dev 2014; 9:5. [PMID: 24594058 PMCID: PMC4016016 DOI: 10.1186/1749-8104-9-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Accepted: 02/18/2014] [Indexed: 11/12/2022] Open
Abstract
Background Neuronal polarization is an essential step of morphogenesis and connectivity in the developing brain. The serine/threonine kinase LKB1 is a key regulator of cell polarity, metabolism, tumorigenesis, and is required for axon formation. It is allosterically regulated by two related and evolutionarily conserved pseudokinases, STe20-Related ADapters (STRADs) α and β. The roles of STRADα and STRADβ in the developing nervous system are not fully defined, nor is it known whether they serve distinct functions. Results We find that STRADα is highly spliced and appears to be the primal STRAD paralog. We report that each STRAD is sufficient for axogenesis and promoting cell survival in the developing cortex. We also reveal a reciprocal protein-stabilizing relationship in vivo between LKB1 and STRADα, whereby STRADα specifically maintains LKB1 protein levels via cytoplasmic compartmentalization. Conclusions We demonstrate a novel role for STRADβ in axogenesis and also show for the first time in vivo that STRADα, but not STRADβ, is responsible for LKB1 protein stability.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Anthony P Barnes
- Department of Pediatrics-Doernbecher, Children's Hospital, Portland, OR 97239, USA.
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Akhshi TK, Wernike D, Piekny A. Microtubules and actin crosstalk in cell migration and division. Cytoskeleton (Hoboken) 2013; 71:1-23. [DOI: 10.1002/cm.21150] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/02/2013] [Accepted: 10/06/2013] [Indexed: 12/22/2022]
Affiliation(s)
| | - Denise Wernike
- Department of Biology; Concordia University; Montreal Quebec Canada
| | - Alisa Piekny
- Department of Biology; Concordia University; Montreal Quebec Canada
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Motegi F, Seydoux G. The PAR network: redundancy and robustness in a symmetry-breaking system. Philos Trans R Soc Lond B Biol Sci 2013; 368:20130010. [PMID: 24062581 PMCID: PMC3785961 DOI: 10.1098/rstb.2013.0010] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
To become polarized, cells must first 'break symmetry'. Symmetry breaking is the process by which an unpolarized, symmetric cell develops a singularity, often at the cell periphery, that is used to develop a polarity axis. The Caenorhabditis elegans zygote breaks symmetry under the influence of the sperm-donated centrosome, which causes the PAR polarity regulators to sort into distinct anterior and posterior cortical domains. Modelling analyses have shown that cortical flows induced by the centrosome combined with antagonism between anterior and posterior PARs (mutual exclusion) are sufficient, in principle, to break symmetry, provided that anterior and posterior PAR activities are precisely balanced. Experimental evidence indicates, however, that the system is surprisingly robust to changes in cortical flows, mutual exclusion and PAR balance. We suggest that this robustness derives from redundant symmetry-breaking inputs that engage two positive feedback loops mediated by the anterior and posterior PAR proteins. In particular, the PAR-2 feedback loop stabilizes the polarized state by creating a domain where posterior PARs are immune to exclusion by anterior PARs. The two feedback loops in the PAR network share characteristics with the two feedback loops in the Cdc42 polarization network of Saccharomyces cerevisiae.
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Affiliation(s)
- Fumio Motegi
- Temasek Lifesciences Laboratory, National University of Singapore, , 1 Research Link, Singapore 117604, Republic of Singapore
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Courchet J, Lewis TL, Lee S, Courchet V, Liou DY, Aizawa S, Polleux F. Terminal axon branching is regulated by the LKB1-NUAK1 kinase pathway via presynaptic mitochondrial capture. Cell 2013; 153:1510-25. [PMID: 23791179 DOI: 10.1016/j.cell.2013.05.021] [Citation(s) in RCA: 242] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 04/01/2013] [Accepted: 05/08/2013] [Indexed: 10/26/2022]
Abstract
The molecular mechanisms underlying the axon arborization of mammalian neurons are poorly understood but are critical for the establishment of functional neural circuits. We identified a pathway defined by two kinases, LKB1 and NUAK1, required for cortical axon branching in vivo. Conditional deletion of LKB1 after axon specification or knockdown of NUAK1 drastically reduced axon branching in vivo, whereas their overexpression was sufficient to increase axon branching. The LKB1-NUAK1 pathway controls mitochondria immobilization in axons. Using manipulation of Syntaphilin, a protein necessary and sufficient to arrest mitochondrial transport specifically in the axon, we demonstrate that the LKB1-NUAK1 kinase pathway regulates axon branching by promoting mitochondria immobilization. Finally, we show that LKB1 and NUAK1 are necessary and sufficient to immobilize mitochondria specifically at nascent presynaptic sites. Our results unravel a link between presynaptic mitochondrial capture and axon branching.
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Affiliation(s)
- Julien Courchet
- Dorris Neuroscience Center and Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, CA 92037-1000, USA
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Noatynska A, Tavernier N, Gotta M, Pintard L. Coordinating cell polarity and cell cycle progression: what can we learn from flies and worms? Open Biol 2013; 3:130083. [PMID: 23926048 PMCID: PMC3758543 DOI: 10.1098/rsob.130083] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Spatio-temporal coordination of events during cell division is crucial for animal development. In recent years, emerging data have strengthened the notion that tight coupling of cell cycle progression and cell polarity in dividing cells is crucial for asymmetric cell division and ultimately for metazoan development. Although it is acknowledged that such coupling exists, the molecular mechanisms linking the cell cycle and cell polarity machineries are still under investigation. Key cell cycle regulators control cell polarity, and thus influence cell fate determination and/or differentiation, whereas some factors involved in cell polarity regulate cell cycle timing and proliferation potential. The scope of this review is to discuss the data linking cell polarity and cell cycle progression, and the importance of such coupling for asymmetric cell division. Because studies in model organisms such as Caenorhabditis elegans and Drosophila melanogaster have started to reveal the molecular mechanisms of this coordination, we will concentrate on these two systems. We review examples of molecular mechanisms suggesting a coupling between cell polarity and cell cycle progression.
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Affiliation(s)
- Anna Noatynska
- Department of Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 rue Michel Servet, 1211 Geneva, Switzerland
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