1
|
Hudson J, Paul S, Veraksa A, Ghabrial A, Harvey KF, Poon C. NDR kinase tricornered genetically interacts with Ccm3 and metabolic enzymes in Drosophila melanogaster tracheal development. G3 (BETHESDA, MD.) 2023; 13:6991444. [PMID: 36653023 PMCID: PMC9997570 DOI: 10.1093/g3journal/jkad013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 07/18/2022] [Accepted: 12/14/2022] [Indexed: 01/20/2023]
Abstract
The Germinal Center Kinase III (GckIII) pathway is a Hippo-like kinase module defined by sequential activation of Ste20 kinases Thousand and One (Tao) and GckIII, followed by nuclear dbf2-related (NDR) kinase Tricornered (Trc). We previously uncovered a role for the GckIII pathway in Drosophila melanogaster tracheal (respiratory) tube morphology. The trachea form a network of branched epithelial tubes essential for oxygen transport, and are structurally analogous to branched tubular organs in vertebrates, such as the vascular system. In the absence of GckIII pathway function, aberrant dilations form in tracheal tubes characterized by mislocalized junctional and apical proteins, suggesting that the pathway is important in maintaining tube integrity in development. Here, we observed a genetic interaction between trc and Cerebral cavernous malformations 3 (Ccm3), the Drosophila ortholog of a human vascular disease gene, supporting our hypothesis that the GckIII pathway functions downstream of Ccm3 in trachea, and potentially in the vertebrate cerebral vasculature. However, how GckIII pathway signaling is regulated and the mechanisms that underpin its function in tracheal development are unknown. We undertook biochemical and genetic approaches to identify proteins that interact with Trc, the most downstream GckIII pathway kinase. We found that known GckIII and NDR scaffold proteins are likely to control GckIII pathway signaling in tracheal development, consistent with their conserved roles in Hippo-like modules. Furthermore, we show genetic interactions between trc and multiple enzymes in glycolysis and oxidative phosphorylation, suggesting a potential function of the GckIII pathway in integrating cellular energy requirements with maintenance of tube integrity.
Collapse
Affiliation(s)
- Joshua Hudson
- Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, Victoria 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Sayantanee Paul
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Alexey Veraksa
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Amin Ghabrial
- Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Kieran F Harvey
- Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, Victoria 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria 3010, Australia.,Department of Anatomy and Developmental Biology, and Biomedicine Discovery Institute, Monash University, Clayton 3800, Australia
| | - Carole Poon
- Peter MacCallum Cancer Centre, 305 Grattan Street, Melbourne, Victoria 3000, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria 3010, Australia
| |
Collapse
|
2
|
Fission Yeast Rho1p-GEFs: From Polarity and Cell Wall Synthesis to Genome Stability. Int J Mol Sci 2022; 23:ijms232213888. [PMID: 36430366 PMCID: PMC9697909 DOI: 10.3390/ijms232213888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Rho1p is a membrane-associated protein that belongs to the Rho family of small GTPases. These proteins coordinate processes such as actin remodelling and polarised secretion to maintain the shape and homeostasis of yeast cells. In response to extracellular stimuli, Rho1p undergoes conformational switching between a guanosine triphosphate (GTP)-bound active state and a guanosine diphosphate (GDP)-bound inactive state. Cycling is improved with guanine nucleotide exchange factor (GEF) activity necessary to activate signalling and GTPase activating protein (GAP) activity required for subsequent signal depletion. This review focuses on fission yeast Rho1p GEFs, Rgf1p, Rgf2p, and Rgf3p that belong to the family of DH-PH domain-containing Dbl-related GEFs. They are multi-domain proteins that detect biological signals that induce or inhibit their catalytic activity over Rho1p. Each of them activates Rho1p in different places and times. Rgf1p acts preferentially during polarised growth. Rgf2p is required for sporulation, and Rgf3p plays an essential function in septum synthesis. In addition, we outline the noncanonical roles of Rho1p-GEFs in genomic instability.
Collapse
|
3
|
Sinha D, Ivan D, Gibbs E, Chetluru M, Goss J, Chen Q. Fission yeast polycystin Pkd2p promotes cell size expansion and antagonizes the Hippo-related SIN pathway. J Cell Sci 2022; 135:274457. [PMID: 35099006 PMCID: PMC8919332 DOI: 10.1242/jcs.259046] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 01/14/2022] [Indexed: 11/20/2022] Open
Abstract
Polycystins are conserved mechanosensitive channels whose mutations lead to the common human renal disorder autosomal dominant polycystic kidney disease (ADPKD). Previously, we discovered that the plasma membrane-localized fission yeast polycystin homolog Pkd2p is an essential protein required for cytokinesis; however, its role remains unclear. Here, we isolated a novel temperature-sensitive pkd2 mutant, pkd2-B42. Among the strong growth defects of this mutant, the most striking was that many mutant cells often lost a significant portion of their volume in just 5 min followed by a gradual recovery, a process that we termed 'deflation'. Unlike cell lysis, deflation did not result in plasma membrane rupture and occurred independently of cell cycle progression. The tip extension of pkd2-B42 cells was 80% slower than that of wild-type cells, and their turgor pressure was 50% lower. Both pkd2-B42 and the hypomorphic depletion mutant pkd2-81KD partially rescued mutants of the septation initiation network (SIN), a yeast Hippo-related signaling pathway, by preventing cell lysis, enhancing septum formation and doubling the number of Sid2p and Mob1p molecules at the spindle pole bodies. We conclude that Pkd2p promotes cell size expansion during interphase by regulating turgor pressure and antagonizes the SIN during cytokinesis. This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Debatrayee Sinha
- Department of Biological Sciences, The University of Toledo, 2801 West Bancroft St, Toledo, OH 43606, USA
| | - Denisa Ivan
- Department of Biological Sciences, The University of Toledo, 2801 West Bancroft St, Toledo, OH 43606, USA
| | - Ellie Gibbs
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02482, USA
| | - Madhurya Chetluru
- Department of Biological Sciences, The University of Toledo, 2801 West Bancroft St, Toledo, OH 43606, USA
| | - John Goss
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA 02482, USA
| | - Qian Chen
- Department of Biological Sciences, The University of Toledo, 2801 West Bancroft St, Toledo, OH 43606, USA,Author for correspondence ()
| |
Collapse
|
4
|
Rich-Robinson J, Russell A, Mancini E, Das M. Cdc42 reactivation at growth sites is regulated by local cell-cycle-dependent loss of its GTPase-activating protein Rga4 in fission yeast. J Cell Sci 2021; 134:272049. [PMID: 34523683 DOI: 10.1242/jcs.259291] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 12/18/2022] Open
Abstract
In fission yeast, polarized cell growth stops during division and resumes after cytokinesis completes and cells separate. It is unclear how growth reactivation is timed to occur immediately after cell separation. We uncoupled these sequential events by delaying cytokinesis with a temporary Latrunculin A treatment. Mitotic cells recovering from treatment initiate end growth during septation, displaying a polar elongation simultaneous with septation (PrESS) phenotype. PrESS cell ends reactivate Cdc42, a major regulator of polarized growth, during septation, but at a fixed time after anaphase B. A candidate screen implicates Rga4, a negative regulator of Cdc42, in this process. We show that Rga4 appears punctate at the cell sides during G2, but is diffuse during mitosis, extending to the ends. Although the Morphogenesis Orb6 (MOR) pathway is known to promote cell separation and growth by activating protein synthesis, we find that, for polarized growth, removal of Rga4 from the ends is also necessary. Therefore, we propose that growth resumes after division once the MOR pathway is activated and the ends lose Rga4 in a cell-cycle-dependent manner.
Collapse
Affiliation(s)
- Julie Rich-Robinson
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Afton Russell
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Eleanor Mancini
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| | - Maitreyi Das
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
| |
Collapse
|
5
|
Roncero C, Celador R, Sánchez N, García P, Sánchez Y. The Role of the Cell Integrity Pathway in Septum Assembly in Yeast. J Fungi (Basel) 2021; 7:jof7090729. [PMID: 34575767 PMCID: PMC8471060 DOI: 10.3390/jof7090729] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 12/22/2022] Open
Abstract
Cytokinesis divides a mother cell into two daughter cells at the end of each cell cycle and proceeds via the assembly and constriction of a contractile actomyosin ring (CAR). Ring constriction promotes division furrow ingression, after sister chromatids are segregated to opposing sides of the cleavage plane. Cytokinesis contributes to genome integrity because the cells that fail to complete cytokinesis often reduplicate their chromosomes. While in animal cells, the last steps of cytokinesis involve extracellular matrix remodelling and mid-body abscission, in yeast, CAR constriction is coupled to the synthesis of a polysaccharide septum. To preserve cell integrity during cytokinesis, fungal cells remodel their cell wall through signalling pathways that connect receptors to downstream effectors, initiating a cascade of biological signals. One of the best-studied signalling pathways is the cell wall integrity pathway (CWI) of the budding yeast Saccharomyces cerevisiae and its counterpart in the fission yeast Schizosaccharomyces pombe, the cell integrity pathway (CIP). Both are signal transduction pathways relying upon a cascade of MAP kinases. However, despite strong similarities in the assembly of the septa in both yeasts, there are significant mechanistic differences, including the relationship of this process with the cell integrity signalling pathways.
Collapse
|
6
|
Madencioglu DA, Çalışkan G, Yuanxiang P, Rehberg K, Demiray YE, Kul E, Engler A, Hayani H, Bergado-Acosta JR, Kummer A, Müller I, Song I, Dityatev A, Kähne T, Kreutz MR, Stork O. Transgenic modeling of Ndr2 gene amplification reveals disturbance of hippocampus circuitry and function. iScience 2021; 24:102868. [PMID: 34381982 PMCID: PMC8340122 DOI: 10.1016/j.isci.2021.102868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/19/2021] [Accepted: 07/14/2021] [Indexed: 11/18/2022] Open
Abstract
Duplications and deletions of short chromosomal fragments are increasingly recognized as the cause for rare neurodevelopmental conditions and disorders. The NDR2 gene encodes a protein kinase important for neuronal development and is part of a microduplication region on chromosome 12 that is associated with intellectual disabilities, autism, and epilepsy. We developed a conditional transgenic mouse with increased Ndr2 expression in postmigratory forebrain neurons to study the consequences of an increased gene dosage of this Hippo pathway kinase on brain circuitry and cognitive functions. Our analysis reveals reduced terminal fields and synaptic transmission of hippocampal mossy fibers, altered hippocampal network activity, and deficits in mossy fiber-dependent behaviors. Reduced doublecortin expression and protein interactome analysis indicate that transgenic Ndr2 disturbs the maturation of granule cells in the dentate gyrus. Together, our data suggest that increased expression of Ndr2 may critically contribute to the development of intellectual disabilities upon gene amplification.
Collapse
Affiliation(s)
- Deniz A. Madencioglu
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Gürsel Çalışkan
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39102Magdeburg, Germany
| | - Pingan Yuanxiang
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39112Magdeburg, Germany
| | - Kati Rehberg
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Yunus E. Demiray
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Emre Kul
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Alexander Engler
- Institute of Experimental Internal Medicine, Otto-von-Guericke-University, 39120Magdeburg, Germany
| | - Hussam Hayani
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases, 39120Magdeburg, Germany
| | - Jorge R. Bergado-Acosta
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39102Magdeburg, Germany
| | - Anne Kummer
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
| | - Iris Müller
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39102Magdeburg, Germany
| | - Inseon Song
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases, 39120Magdeburg, Germany
| | - Alexander Dityatev
- Molecular Neuroplasticity Group, German Center for Neurodegenerative Diseases, 39120Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39102Magdeburg, Germany
- Medical Faculty, Otto-von-Guericke-University, 39120Magdeburg, Germany
| | - Thilo Kähne
- Institute of Experimental Internal Medicine, Otto-von-Guericke-University, 39120Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39102Magdeburg, Germany
| | - Michael R. Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39112Magdeburg, Germany
- Leibniz Group 'Dendritic Organelles and Synaptic Function', University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology, ZMNH, 20251Hamburg, Germany
- Center for Behavioral Brain Sciences, 39102Magdeburg, Germany
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39102Magdeburg, Germany
| |
Collapse
|
7
|
Mak T, Jones AW, Nurse P. The TOR-dependent phosphoproteome and regulation of cellular protein synthesis. EMBO J 2021; 40:e107911. [PMID: 34296454 PMCID: PMC8365262 DOI: 10.15252/embj.2021107911] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/28/2021] [Accepted: 06/09/2021] [Indexed: 01/21/2023] Open
Abstract
Cell growth is orchestrated by a number of interlinking cellular processes. Components of the TOR pathway have been proposed as potential regulators of cell growth, but little is known about their immediate effects on protein synthesis in response to TOR‐dependent growth inhibition. Here, we present a resource providing an in‐depth characterisation of Schizosaccharomyces pombe phosphoproteome in relation to changes observed in global cellular protein synthesis upon TOR inhibition. We find that after TOR inhibition, the rate of protein synthesis is rapidly reduced and that notable phosphorylation changes are observed in proteins involved in a range of cellular processes. We show that this reduction in protein synthesis rates upon TOR inhibition is not dependent on S6K activity, but is partially dependent on the S. pombe homologue of eIF4G, Tif471. Our study demonstrates the impact of TOR‐dependent phospho‐regulation on the rate of protein synthesis and establishes a foundational resource for further investigation of additional TOR‐regulated targets both in fission yeast and other eukaryotes.
Collapse
Affiliation(s)
- Tiffany Mak
- Cell Cycle Laboratory, The Francis Crick Institute, London, UK
| | - Andrew W Jones
- Cell Cycle Laboratory, The Francis Crick Institute, London, UK.,Protein Analysis and Proteomics Platform, The Francis Crick Institute, London, UK
| | - Paul Nurse
- Cell Cycle Laboratory, The Francis Crick Institute, London, UK.,Laboratory of Yeast Genetics and Cell Biology, Rockefeller University, New York, NY, USA
| |
Collapse
|
8
|
Edreira T, Celador R, Manjón E, Sánchez Y. A novel checkpoint pathway controls actomyosin ring constriction trigger in fission yeast. eLife 2020; 9:59333. [PMID: 33103994 PMCID: PMC7661037 DOI: 10.7554/elife.59333] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 10/24/2020] [Indexed: 12/12/2022] Open
Abstract
In fission yeast, the septation initiation network (SIN) ensures temporal coordination between actomyosin ring (CAR) constriction with membrane ingression and septum synthesis. However, questions remain about CAR regulation under stress conditions. We show that Rgf1p (Rho1p GEF), participates in a delay of cytokinesis under cell wall stress (blankophor, BP). BP did not interfere with CAR assembly or the rate of CAR constriction, but did delay the onset of constriction in the wild type cells but not in the rgf1Δ cells. This delay was also abolished in the absence of Pmk1p, the MAPK of the cell integrity pathway (CIP), leading to premature abscission and a multi-septated phenotype. Moreover, cytokinesis delay correlates with maintained SIN signaling and depends on the SIN to be achieved. Thus, we propose that the CIP participates in a checkpoint, capable of triggering a CAR constriction delay through the SIN pathway to ensure that cytokinesis terminates successfully.
Collapse
Affiliation(s)
- Tomás Edreira
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Rubén Celador
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Elvira Manjón
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| | - Yolanda Sánchez
- Instituto de Biología Funcional y Genómica, CSIC/Universidad de Salamanca and Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
| |
Collapse
|
9
|
Kume K. Control of cellular organization and its coordination with the cell cycle. Biosci Biotechnol Biochem 2020; 84:869-875. [PMID: 31987003 DOI: 10.1080/09168451.2020.1717926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Cells organize themselves to maintain proper shape, structure, and size during growth and division for their cellular functions. However, how these cellular organizations coordinate with the cell cycle is not well understood. This review focuses on cell morphogenesis and size of the membrane-bound nucleus in the fission yeast Schizosaccharomyces pombe. Growth polarity, an important factor for cell morphogenesis, in rod-shaped fission yeast is restricted to the cell tips and dynamically changes depending on the cell cycle stage. Furthermore, nuclear size in fission yeast is proportional to the cell size, resulting in a constant ratio between nuclear volume and cellular volume (N/C ratio). This review summarizes the signaling pathway(s) involved in growth polarity control and key factors involved in N/C ratio control and provides their roles in coordination between cell organization and the cell cycle.
Collapse
Affiliation(s)
- Kazunori Kume
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Japan
| |
Collapse
|
10
|
Swaffer MP, Jones AW, Flynn HR, Snijders AP, Nurse P. Quantitative Phosphoproteomics Reveals the Signaling Dynamics of Cell-Cycle Kinases in the Fission Yeast Schizosaccharomyces pombe. Cell Rep 2019; 24:503-514. [PMID: 29996109 PMCID: PMC6057490 DOI: 10.1016/j.celrep.2018.06.036] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 04/16/2018] [Accepted: 06/08/2018] [Indexed: 11/19/2022] Open
Abstract
Multiple protein kinases regulate cell-cycle progression, of which the cyclin-dependent kinases (CDKs) are thought to act as upstream master regulators. We have used quantitative phosphoproteomics to analyze the fission yeast cell cycle at sufficiently high temporal resolution to distinguish fine-grain differences in substrate phosphorylation dynamics on a proteome-wide scale. This dataset provides a useful resource for investigating the regulatory dynamics of cell-cycle kinases and their substrates. For example, our analysis indicates that the substrates of different mitotic kinases (CDK, NIMA-related, Polo-like, and Aurora) are phosphorylated in sequential, kinase-specific waves during mitosis. Phosphoproteomics analysis after chemical-genetic manipulation of CDK activity suggests that the timing of these waves is established by the differential dependency of the downstream kinases on upstream CDK. We have also examined the temporal organization of phosphorylation during G1/S, as well as the coordination between the NDR-related kinase Orb6, which controls polarized growth, and other cell-cycle kinases. Global analysis of phosphorylation dynamics during the fission yeast cell cycle Reveals kinase-specific waves of phosphorylation throughout interphase and mitosis Mitotic kinases show significantly different dependencies on upstream CDK activity Kinases directly downstream of CDK mediate earlier waves of mitotic phosphorylation
Collapse
Affiliation(s)
- Matthew P Swaffer
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
| | - Andrew W Jones
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Protein Analysis and Proteomics Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Helen R Flynn
- Protein Analysis and Proteomics Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Ambrosius P Snijders
- Protein Analysis and Proteomics Platform, The Francis Crick Institute, London NW1 1AT, UK
| | - Paul Nurse
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, UK; Laboratory of Yeast Genetics and Cell Biology, Rockefeller University, New York, NY 10065, USA
| |
Collapse
|
11
|
Willet AH, DeWitt AK, Beckley JR, Clifford DM, Gould KL. NDR Kinase Sid2 Drives Anillin-like Mid1 from the Membrane to Promote Cytokinesis and Medial Division Site Placement. Curr Biol 2019; 29:1055-1063.e2. [PMID: 30853434 DOI: 10.1016/j.cub.2019.01.075] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 01/09/2019] [Accepted: 01/29/2019] [Indexed: 11/18/2022]
Abstract
In animals and fungi, cytokinesis is facilitated by the constriction of an actomyosin contractile ring (CR) [1]. In Schizosaccharomyces pombe, the CR forms mid-cell during mitosis from clusters of proteins at the medial cell cortex called nodes [2]. The anillin-like protein Mid1 localizes to nodes and is required for CR assembly at mid-cell [3]. When CR constriction begins, Mid1 leaves the division site. How Mid1 disassociates and whether this step is important for cytokinetic progression has been unknown. The septation initiation network (SIN), analogous to the Hippo pathway of multicellular organisms, is a signaling cascade that triggers node dispersal, CR assembly and constriction, and septum formation [4, 5]. We report that the terminal SIN kinase, Sid2 [6], phosphorylates Mid1 to drive its removal from the cortex at CR constriction onset. A Mid1 mutant that cannot be phosphorylated by Sid2 remains cortical during cytokinesis, over-accumulates in interphase nodes following cell division in a manner dependent on the SAD kinase Cdr2, advances the G2/M transition, precociously recruits other CR components to nodes, pulls Cdr2 aberrantly into the CR, and reduces rates of CR maturation and constriction. When combined with cdr2 mutants that affect node assembly or disassembly, gross defects in division site positioning result. Our findings identify Mid1 as a key Sid2 substrate for SIN-mediated remodeling of the division site for efficient cytokinesis and provide evidence that nodes serve to integrate signals coordinating cell cycle progression and cytokinesis.
Collapse
Affiliation(s)
- Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Ashley K DeWitt
- Grand Valley State University, Department of Cell and Molecular Biology, Allendale, MI 49401, USA
| | - Janel R Beckley
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Dawn M Clifford
- Grand Valley State University, Department of Cell and Molecular Biology, Allendale, MI 49401, USA
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| |
Collapse
|
12
|
Kwon L, Magee EM, Crayton A, Goss JW. Fission yeast type 2 node proteins Blt1p and Gef2p cooperate to ensure timely completion of cytokinesis. BMC Mol Cell Biol 2019; 20:1. [PMID: 31041892 PMCID: PMC6446504 DOI: 10.1186/s12860-018-0182-z] [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: 06/01/2018] [Accepted: 12/14/2018] [Indexed: 12/01/2022] Open
Abstract
Background The conserved NDR-family kinase Sid2p localizes to the contractile ring during fission yeast cytokinesis to promote ring constriction, septation, and completion of cell division. Previous studies have found that the Type 2 interphase node proteins Blt1p and Gef2p contribute to localization of Sid2p and its regulatory protein Mob1p at the division site. However, their relative contributions and whether they operate in the same or parallel pathways has been unclear. In this study, we quantify the respective roles of Blt1p and Gef2p in Sid2p/Mob1p recruitment and characterize the effect of single and double deletion mutants on contractile ring dynamics and completion of cell division. Results Using quantitative confocal fluorescence microscopy, we measured Sid2p and Mob1p recruitment to the division site in blt1∆, gef2∆, and blt1∆/gef2∆ mutant cells. We observed an equivalent decrease in Sid2p/Mob1p localization for both single and double mutants. Though assembly of the contractile ring is normal in these mutants, the reduction in Sid2p/Mob1p at the division site delayed the onset of contractile ring constriction and completion of division. We quantified localization of Blt1p and Gef2p at the medial cortex throughout the cell cycle and found that Blt1p localization to interphase nodes and the contractile ring is independent of Gef2p. However, Gef2p localization to the contractile ring is decreased in blt1∆ mutants. Conclusions Blt1p and Gef2p work in the same pathway, rather than in parallel, to localize the NDR-family kinase Sid2p and its regulatory partner Mob1p to the division site, thereby promoting timely completion of cell division. Future studies are necessary to understand how additional fission yeast cytokinesis proteins work with these Type 2 interphase node components to promote Sid2p/Mob1p recruitment. Electronic supplementary material The online version of this article (10.1186/s12860-018-0182-z) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Lois Kwon
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA, 02481, USA
| | - Emma M Magee
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA, 02481, USA
| | - Alexis Crayton
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA, 02481, USA
| | - John W Goss
- Department of Biological Sciences, Wellesley College, 106 Central Street, Wellesley, MA, 02481, USA.
| |
Collapse
|
13
|
Zheng S, Dong F, Rasul F, Yao X, Jin QW, Zheng F, Fu C. Septins regulate the equatorial dynamics of the separation initiation network kinase Sid2p and glucan synthases to ensure proper cytokinesis. FEBS J 2018; 285:2468-2480. [PMID: 29722930 DOI: 10.1111/febs.14487] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/18/2018] [Accepted: 04/24/2018] [Indexed: 12/31/2022]
Abstract
Septins generally function as scaffolds and as cortical barriers to restrict the diffusion of membrane proteins. In the fission yeast Schizosaccharomyces pombe, septins form a ring structure at the septum after spindle breakdown during the constriction of the contractile actomyosin ring (CAR) and serve as a scaffold to recruit glucanases to mediate ultimate daughter cell separation. Despite this, it remains unclear if septins play any significant roles before the cell separation during cytokinesis. Employing live cell microscopy, we carefully examined SIN (Septation Initiation Network) signaling and glucan synthases, two key factors ensuring proper function of the CAR. In the absence of the core septin component Spn1p, the formation of a compact CAR is advanced and the CAR constriction rate is slightly but significantly decreased. Moreover, the SIN kinase Sid2p and the glucan synthases Bgs1p and Ags1p form an equatorial ring quite prematurely, but their maintenance at the equatorial region is diminished spn1Δ cells. These findings suggest that septins act as key players in an accurate establishment and the maintenance of CAR by orchestrating the equatorial dynamics of Sid2p and glucan synthases. Hence, this work demonstrates that, in addition to their function during ultimate cell septation, septins have important roles in regulating earlier cytokinetic events, including CAR assembly and constriction, SIN signaling, and the cortical dynamics of the glucan synthases.
Collapse
Affiliation(s)
- Shengnan Zheng
- Chinese Academy of Sciences Center for Excellence in Molecular Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.,Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Fenfen Dong
- Chinese Academy of Sciences Center for Excellence in Molecular Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.,Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Faiz Rasul
- Chinese Academy of Sciences Center for Excellence in Molecular Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.,Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Xuebiao Yao
- Chinese Academy of Sciences Center for Excellence in Molecular Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.,Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Quan-Wen Jin
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Fujian, China
| | - Fan Zheng
- Chinese Academy of Sciences Center for Excellence in Molecular Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.,Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Chuanhai Fu
- Chinese Academy of Sciences Center for Excellence in Molecular Cell Biology, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.,Anhui Key Laboratory for Cellular Dynamics & Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| |
Collapse
|
14
|
Keough MT, Penniston TL, Vilhena-Churchill N, Michael Bagby R, Quilty LC. Depression symptoms and reasons for gambling sequentially mediate the associations between insecure attachment styles and problem gambling. Addict Behav 2018; 78:166-172. [PMID: 29175293 DOI: 10.1016/j.addbeh.2017.11.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/09/2017] [Accepted: 11/09/2017] [Indexed: 11/28/2022]
Abstract
One of the central pathways to problem gambling (PG) is gambling to cope with negative moods, which is a cardinal feature of depression. Insecure attachment styles are also etiologically related to depression; and, therefore, by extension, those who are insecurely attached may engage in excessive gambling behaviors to cope with depression. In this study, we aimed to evaluate this and to this end predicted that depression severity and coping motives for gambling would conjointly mediate the relations between insecure attachment styles and PG. Data came from a larger investigation of PG within mood disorders. Participants exhibited a lifetime depressive or bipolar disorder and endorsed a mood episode within the past ten years. Participants (N=275) completed self-report measures during a two-day assessment. Path analysis supported two main indirect effects. First, anxious attachment predicted elevated depression, which in turn predicted increased coping motives for gambling, which subsequently predicted greater PG severity. Second, this double mediational pathway was also observed for avoidant attachment. Results suggest that insecure attachment relates to PG via depressive symptoms and coping-related gambling motives. Mood symptoms and associated gambling motives are malleable and are promising targets of gambling interventions for insecurely attached individuals.
Collapse
Affiliation(s)
- Matthew T Keough
- University of Manitoba, Department of Psychology, 190 Dysart Road, P314 Duff Roblin Building, Winnipeg, MB R3T 2N2, Canada.
| | - Trinda L Penniston
- University of Manitoba, Department of Psychology, 190 Dysart Road, P314 Duff Roblin Building, Winnipeg, MB R3T 2N2, Canada
| | - Natalie Vilhena-Churchill
- Altum Health, University Health Network, Krembil Discovery Tower, 399, Bathurst St., Toronto, Ontario M5T 2S8, Canada
| | - R Michael Bagby
- University of Toronto, Departments of Psychology and Psychiatry, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Lena C Quilty
- Centre for Addiction and Mental Health, Campbell Family Mental Health Research Institute, 100 Stokes Street, Bell Gateway Building, Toronto, Ontario M6J 1H4, Canada; University of Toronto, Department of Psychiatry, 250 College St., Toronto, Ontario M5T 1R8, Canada
| |
Collapse
|
15
|
Abstract
A conserved molecular machinery centered on the Cdc42 GTPase regulates cell polarity in diverse organisms. Here we review findings from budding and fission yeasts that reveal both a conserved core polarity circuit and several adaptations that each organism exploits to fulfill the needs of its lifestyle. The core circuit involves positive feedback by local activation of Cdc42 to generate a cluster of concentrated GTP-Cdc42 at the membrane. Species-specific pathways regulate the timing of polarization during the cell cycle, as well as the location and number of polarity sites.
Collapse
Affiliation(s)
- Jian-Geng Chiou
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710;
| | - Mohan K Balasubramanian
- Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Daniel J Lew
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710;
| |
Collapse
|
16
|
McDonald NA, Lind AL, Smith SE, Li R, Gould KL. Nanoscale architecture of the Schizosaccharomyces pombe contractile ring. eLife 2017; 6:28865. [PMID: 28914606 PMCID: PMC5779233 DOI: 10.7554/elife.28865] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/14/2017] [Indexed: 12/13/2022] Open
Abstract
The contractile ring is a complex molecular apparatus which physically divides many eukaryotic cells. Despite knowledge of its protein composition, the molecular architecture of the ring is not known. Here we have applied super-resolution microscopy and FRET to determine the nanoscale spatial organization of Schizosaccharomyces pombe contractile ring components relative to the plasma membrane. Similar to other membrane-tethered actin structures, we find proteins localize in specific layers relative to the membrane. The most membrane-proximal layer (0–80 nm) is composed of membrane-binding scaffolds, formin, and the tail of the essential myosin-II. An intermediate layer (80–160 nm) consists of a network of cytokinesis accessory proteins as well as multiple signaling components which influence cell division. Farthest from the membrane (160–350 nm) we find F-actin, the motor domains of myosins, and a major F-actin crosslinker. Circumferentially within the ring, multiple proteins proximal to the membrane form clusters of different sizes, while components farther from the membrane are uniformly distributed. This comprehensive organizational map provides a framework for understanding contractile ring function.
Collapse
Affiliation(s)
- Nathan A McDonald
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| | - Abigail L Lind
- Department of Biomedical Informatics, Vanderbilt University Medical Center, Nashville, United States
| | - Sarah E Smith
- Stowers Institute for Medical Research, Kansas City, United States
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
| |
Collapse
|
17
|
Rincon SA, Estravis M, Dingli F, Loew D, Tran PT, Paoletti A. SIN-Dependent Dissociation of the SAD Kinase Cdr2 from the Cell Cortex Resets the Division Plane. Curr Biol 2017; 27:534-542. [PMID: 28162898 DOI: 10.1016/j.cub.2016.12.050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 11/28/2016] [Accepted: 12/22/2016] [Indexed: 11/16/2022]
Abstract
Proper division plane positioning is crucial for faithful chromosome segregation but also influences cell size, position, or fate [1]. In fission yeast, medial division is controlled through negative signaling by the cell tips during interphase and positive signaling by the centrally placed nucleus at mitotic entry [2-4]: the cell geometry network (CGN), controlled by the inhibitory cortical gradient of the DYRK kinase Pom1 emanating from the cell tips, first promotes the medial localization of cytokinetic ring precursors organized by the SAD kinase Cdr2 to pre-define the division plane [5-8]; then, massive nuclear export of the anillin-like protein Mid1 at mitosis entry confirms or readjusts the division plane according to nuclear position and triggers the assembly of a medial contractile ring [5, 9-11]. Strikingly, the Hippo-like septation initiation network (SIN) induces Cdr2 dissociation from cytokinetic precursors at this stage [12-14]. We show here that SIN-dependent phosphorylation of Cdr2 promotes its interaction with the 14-3-3 protein Rad24 that sequesters it in the cytoplasm during cell division. If this interaction is compromised, cytokinetic precursors are asymmetrically distributed in the cortex of newborn cells, leading to asymmetrical division if nuclear signaling is abolished. We conclude that, through this new function, the SIN resets the division plane in newborn cells to ensure medial division.
Collapse
Affiliation(s)
- Sergio A Rincon
- Institut Curie, PSL Research University, CNRS, UMR 144, 75005 Paris, France.
| | - Miguel Estravis
- Institute of Genetics and Development of Rennes, CNRS, UMR 6290, 35043 Rennes Cedex, France
| | - Florent Dingli
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, PSL Research University, 75005 Paris, France
| | - Damarys Loew
- Laboratoire de Spectrométrie de Masse Protéomique, Institut Curie, PSL Research University, 75005 Paris, France
| | - Phong T Tran
- Institut Curie, PSL Research University, CNRS, UMR 144, 75005 Paris, France; Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anne Paoletti
- Institut Curie, PSL Research University, CNRS, UMR 144, 75005 Paris, France.
| |
Collapse
|
18
|
Abstract
SUMMARYAll eukaryotic cells prepare for cell division by forming a "mitotic spindle"-a bipolar machine made from microtubules (MTs) and many associated proteins. This device organizes the already duplicated DNA so one copy of each chromosome attaches to each end of the spindle. Both formation and function of the spindle require controlled MT dynamics, as well as the actions of multiple motor enzymes. Spindle-driven motions separate the duplicated chromosomes into two distinct sets that are then moved toward opposite ends of the cell. The two cells that subsequently form by cytokinesis, therefore, contain all the genes needed to grow and divide again.
Collapse
Affiliation(s)
- J Richard McIntosh
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309-0347
| |
Collapse
|
19
|
Nuñez I, Rodriguez Pino M, Wiley DJ, Das ME, Chen C, Goshima T, Kume K, Hirata D, Toda T, Verde F. Spatial control of translation repression and polarized growth by conserved NDR kinase Orb6 and RNA-binding protein Sts5. eLife 2016; 5. [PMID: 27474797 PMCID: PMC5011436 DOI: 10.7554/elife.14216] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 07/28/2016] [Indexed: 12/18/2022] Open
Abstract
RNA-binding proteins contribute to the formation of ribonucleoprotein (RNP) granules by phase transition, but regulatory mechanisms are not fully understood. Conserved fission yeast NDR (Nuclear Dbf2-Related) kinase Orb6 governs cell morphogenesis in part by spatially controlling Cdc42 GTPase. Here we describe a novel, independent function for Orb6 kinase in negatively regulating the recruitment of RNA-binding protein Sts5 into RNPs to promote polarized cell growth. We find that Orb6 kinase inhibits Sts5 recruitment into granules, its association with processing (P) bodies, and degradation of Sts5-bound mRNAs by promoting Sts5 interaction with 14-3-3 protein Rad24. Many Sts5-bound mRNAs encode essential factors for polarized cell growth, and Orb6 kinase spatially and temporally controls the extent of Sts5 granule formation. Disruption of this control system affects cell morphology and alters the pattern of polarized cell growth, revealing a role for Orb6 kinase in the spatial control of translational repression that enables normal cell morphogenesis.
Collapse
Affiliation(s)
- Illyce Nuñez
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
| | - Marbelys Rodriguez Pino
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
| | - David J Wiley
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
| | - Maitreyi E Das
- Department of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, United States
| | - Chuan Chen
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States
| | - Tetsuya Goshima
- National Research Institute of Brewing, Higashi-Hiroshima, Japan
| | - Kazunori Kume
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan
| | - Dai Hirata
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan
| | - Takashi Toda
- Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan.,The Francis Crick Institute, Lincoln's Inn Fields Laboratory, London, United Kingdom
| | - Fulvia Verde
- Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, United States.,Marine Biological Laboratory, Woods Hole, United States
| |
Collapse
|
20
|
Hergovich A. The Roles of NDR Protein Kinases in Hippo Signalling. Genes (Basel) 2016; 7:genes7050021. [PMID: 27213455 PMCID: PMC4880841 DOI: 10.3390/genes7050021] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/09/2016] [Accepted: 05/10/2016] [Indexed: 12/31/2022] Open
Abstract
The Hippo tumour suppressor pathway has emerged as a critical regulator of tissue growth through controlling cellular processes such as cell proliferation, death, differentiation and stemness. Traditionally, the core cassette of the Hippo pathway includes the MST1/2 protein kinases, the LATS1/2 protein kinases, and the MOB1 scaffold signal transducer, which together regulate the transcriptional co-activator functions of the proto-oncoproteins YAP and TAZ through LATS1/2-mediated phosphorylation of YAP/TAZ. Recent research has identified additional kinases, such as NDR1/2 (also known as STK38/STK38L) and MAP4Ks, which should be considered as novel members of the Hippo core cassette. While these efforts helped to expand our understanding of Hippo core signalling, they also began to provide insights into the complexity and redundancy of the Hippo signalling network. Here, we focus on summarising our current knowledge of the regulation and functions of mammalian NDR kinases, discussing parallels between the NDR pathways in Drosophila and mammals. Initially, we provide a general overview of the cellular functions of NDR kinases in cell cycle progression, centrosome biology, apoptosis, autophagy, DNA damage signalling, immunology and neurobiology. Finally, we put particular emphasis on discussing NDR1/2 as YAP kinases downstream of MST1/2 and MOB1 signalling in Hippo signalling.
Collapse
Affiliation(s)
- Alexander Hergovich
- Cancer Institute, University College London, Paul O'Gorman building, 72 Huntley Street, London WC1E 6BT, UK.
| |
Collapse
|
21
|
Abstract
The mammalian MST kinase family, which is related to the Hippo kinase in Drosophila melanogaster, includes five related proteins: MST1 (also called STK4), MST2 (also called STK3), MST3 (also called STK24), MST4, and YSK1 (also called STK25 or SOK1). MST kinases are emerging as key signaling molecules that influence cell proliferation, organ size, cell migration, and cell polarity. Here we review the regulation and function of these kinases in normal physiology and pathologies, including cancer, endothelial malformations, and autoimmune disease.
Collapse
Affiliation(s)
| | - Erik Sahai
- The Francis Crick Institute, London WC2A 3LY, England, UK
| |
Collapse
|
22
|
Simanis V. Pombe's thirteen - control of fission yeast cell division by the septation initiation network. J Cell Sci 2015; 128:1465-74. [PMID: 25690009 DOI: 10.1242/jcs.094821] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The septation initiation network (SIN) regulates aspects of cell growth and division in Schizosaccharomyces pombe and is essential for cytokinesis. Insufficient signalling results in improper assembly of the contractile ring and failure of cytokinesis, generating multinucleated cells, whereas too much SIN signalling uncouples cytokinesis from the rest of the cell cycle. SIN signalling is therefore tightly controlled to coordinate cytokinesis with chromosome segregation. Signalling originates from the cytoplasmic face of the spindle pole body (SPB), and asymmetric localisation of some SIN proteins to one of the two SPBs during mitosis is important for regulation of the SIN. Recent studies have identified in vivo substrates of the SIN, which include components involved in mitotic control, those of the contractile ring and elements of the signalling pathway regulating polarised growth. The SIN is also required for spore formation following meiosis. This has provided insights into how the SIN performs its diverse functions in the cell cycle and shed new light on its regulation.
Collapse
Affiliation(s)
- Viesturs Simanis
- École Polytechnique Fédérale de Lausanne School of Life Sciences (EPFL-SV), Swiss Institute For Experimental Cancer Research (ISREC), UPSIM, SV2.1830, Station 19, CH-1015 Lausanne, Switzerland
| |
Collapse
|
23
|
Wachowicz P, Chasapi A, Krapp A, Cano Del Rosario E, Schmitter D, Sage D, Unser M, Xenarios I, Rougemont J, Simanis V. Analysis of S. pombe SIN protein association to the SPB reveals two genetically separable states of the SIN. J Cell Sci 2014; 128:741-54. [PMID: 25501816 DOI: 10.1242/jcs.160150] [Citation(s) in RCA: 10] [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
The Schizosaccharomyces pombe septation initiation network (SIN) regulates cytokinesis, and asymmetric association of SIN proteins with the mitotic spindle pole bodies (SPBs) is important for its regulation. Here, we have used semi-automated image analysis to study SIN proteins in large numbers of wild-type and mutant cells. Our principal conclusions are: first, that the association of Cdc7p with the SPBs in early mitosis is frequently asymmetric, with a bias in favour of the new SPB; second, that the early association of Cdc7p-GFP to the SPB depends on Plo1p but not Spg1p, and is unaffected by mutations that influence its asymmetry in anaphase; third, that Cdc7p asymmetry in anaphase B is delayed by Pom1p and by activation of the spindle assembly checkpoint, and is promoted by Rad24p; and fourth, that the length of the spindle, expressed as a fraction of the length of the cell, at which Cdc7p becomes asymmetric is similar in cells dividing at different sizes. These data reveal that multiple regulatory mechanisms control the SIN in mitosis and lead us to propose a two-state model to describe the SIN.
Collapse
Affiliation(s)
- Paulina Wachowicz
- Cell cycle control laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), SV-ISREC, 1015 Lausanne, Switzerland
| | - Anastasia Chasapi
- Swiss-Prot. Group and Vital-IT Group, Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland
| | - Andrea Krapp
- Cell cycle control laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), SV-ISREC, 1015 Lausanne, Switzerland
| | - Elena Cano Del Rosario
- Cell cycle control laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), SV-ISREC, 1015 Lausanne, Switzerland
| | - Daniel Schmitter
- Biomedical Imaging Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Daniel Sage
- Biomedical Imaging Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Michael Unser
- Biomedical Imaging Group, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ioannis Xenarios
- Swiss-Prot. Group and Vital-IT Group, Swiss Institute of Bioinformatics (SIB), 1015 Lausanne, Switzerland
| | - Jacques Rougemont
- Bioinformatics and Biostatistics Core Facility, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Viesturs Simanis
- Cell cycle control laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), SV-ISREC, 1015 Lausanne, Switzerland
| |
Collapse
|
24
|
Hasan A, Cotobal C, Duncan CDS, Mata J. Systematic analysis of the role of RNA-binding proteins in the regulation of RNA stability. PLoS Genet 2014; 10:e1004684. [PMID: 25375137 PMCID: PMC4222612 DOI: 10.1371/journal.pgen.1004684] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 08/18/2014] [Indexed: 01/18/2023] Open
Abstract
mRNA half-lives are transcript-specific and vary over a range of more than 100-fold in eukaryotic cells. mRNA stabilities can be regulated by sequence-specific RNA-binding proteins (RBPs), which bind to regulatory sequence elements and modulate the interaction of the mRNA with the cellular RNA degradation machinery. However, it is unclear if this kind of regulation is sufficient to explain the large range of mRNA stabilities. To address this question, we examined the transcriptome of 74 Schizosaccharomyces pombe strains carrying deletions in non-essential genes encoding predicted RBPs (86% of all such genes). We identified 25 strains that displayed changes in the levels of between 4 and 104 mRNAs. The putative targets of these RBPs formed biologically coherent groups, defining regulons involved in cell separation, ribosome biogenesis, meiotic progression, stress responses and mitochondrial function. Moreover, mRNAs in these groups were enriched in specific sequence motifs in their coding sequences and untranslated regions, suggesting that they are coregulated at the posttranscriptional level. We performed genome-wide RNA stability measurements for several RBP mutants, and confirmed that the altered mRNA levels were caused by changes in their stabilities. Although RBPs regulate the decay rates of multiple regulons, only 16% of all S. pombe mRNAs were affected in any of the 74 deletion strains. This suggests that other players or mechanisms are required to generate the observed range of RNA half-lives of a eukaryotic transcriptome.
Collapse
Affiliation(s)
- Ayesha Hasan
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Cristina Cotobal
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Caia D. S. Duncan
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Juan Mata
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
| |
Collapse
|
25
|
Cross talk between NDR kinase pathways coordinates cytokinesis with cell separation in Schizosaccharomyces pombe. EUKARYOTIC CELL 2014; 13:1104-12. [PMID: 24972934 DOI: 10.1128/ec.00129-14] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
NDR (nuclear Dbf-2-related) kinases constitute key regulatory nodes in signaling networks that control multiple biological processes such as growth, proliferation, mitotic exit, morphogenesis, and apoptosis. Two NDR pathways called the septation initiation network (SIN) and the morphogenesis Orb6 network (MOR) exist in the fission yeast Schizosaccharomyces pombe. The SIN promotes cytokinesis, and the MOR drives cell separation at the end of cytokinesis and polarized growth during interphase. We showed previously that cross talk exists between these two pathways, with the SIN inhibiting the MOR during cytokinesis through phosphorylation of the MOR component Nak1 by the SIN Sid2 kinase. The reason for this inhibition remained uncertain. We show here that failure to inhibit MOR signaling during cytokinesis results in cell lysis at the site of septum formation. Time-lapse analysis revealed that MOR signaling during cytokinesis causes cells to prematurely initiate septum degradation/cell separation. The cell lysis phenotype is due to premature initiation of cell separation because it can be rescued by mutations in genes required for cell separation/septum degradation. We also shed further light on how the SIN inhibits the MOR. Sid2 phosphorylation of the MOR proteins Sog2 and Nak1 is required to prevent cell lysis during cytokinesis. Together, these results show that SIN inhibition of the MOR enforces proper temporal ordering of cytokinetic events.
Collapse
|
26
|
Rachfall N, Johnson AE, Mehta S, Chen JS, Gould KL. Cdk1 promotes cytokinesis in fission yeast through activation of the septation initiation network. Mol Biol Cell 2014; 25:2250-9. [PMID: 24920823 PMCID: PMC4116299 DOI: 10.1091/mbc.e14-04-0936] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In Schizosaccharomyces pombe, late mitotic events are coordinated with cytokinesis by the septation initiation network (SIN), an essential spindle pole body (SPB)-associated kinase cascade, which controls the formation, maintenance, and constriction of the cytokinetic ring. It is not fully understood how SIN initiation is temporally regulated, but it depends on the activation of the GTPase Spg1, which is inhibited during interphase by the essential bipartite GTPase-activating protein Byr4-Cdc16. Cells are particularly sensitive to the modulation of Byr4, which undergoes cell cycle-dependent phosphorylation presumed to regulate its function. Polo-like kinase, which promotes SIN activation, is partially responsible for Byr4 phosphorylation. Here we show that Byr4 is also controlled by cyclin-dependent kinase (Cdk1)-mediated phosphorylation. A Cdk1 nonphosphorylatable Byr4 phosphomutant displays severe cell division defects, including the formation of elongated, multinucleate cells, failure to maintain the cytokinetic ring, and compromised SPB association of the SIN kinase Cdc7. Our analyses show that Cdk1-mediated phosphoregulation of Byr4 facilitates complete removal of Byr4 from metaphase SPBs in concert with Plo1, revealing an unexpected role for Cdk1 in promoting cytokinesis through activation of the SIN pathway.
Collapse
Affiliation(s)
- Nicole Rachfall
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Alyssa E Johnson
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Sapna Mehta
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| |
Collapse
|
27
|
Proper actin ring formation and septum constriction requires coordinated regulation of SIN and MOR pathways through the germinal centre kinase MST-1. PLoS Genet 2014; 10:e1004306. [PMID: 24762679 PMCID: PMC3998894 DOI: 10.1371/journal.pgen.1004306] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 02/25/2014] [Indexed: 12/17/2022] Open
Abstract
Nuclear DBF2p-related (NDR) kinases constitute a functionally conserved protein family of eukaryotic regulators that control cell division and polarity. In fungi, they function as effector kinases of the morphogenesis (MOR) and septation initiation (SIN) networks and are activated by pathway-specific germinal centre (GC) kinases. We characterized a third GC kinase, MST-1, that connects both kinase cascades. Genetic and biochemical interactions with SIN components and life cell imaging identify MST-1 as SIN-associated kinase that functions in parallel with the GC kinase SID-1 to activate the SIN-effector kinase DBF-2. SID-1 and MST-1 are both regulated by the upstream SIN kinase CDC-7, yet in an opposite manner. Aberrant cortical actomyosin rings are formed in Δmst-1, which resulted in mis-positioned septa and irregular spirals, indicating that MST-1-dependent regulation of the SIN is required for proper formation and constriction of the septal actomyosin ring. However, MST-1 also interacts with several components of the MOR network and modulates MOR activity at multiple levels. MST-1 functions as promiscuous enzyme and also activates the MOR effector kinase COT-1 through hydrophobic motif phosphorylation. In addition, MST-1 physically interacts with the MOR kinase POD-6, and dimerization of both proteins inactivates the GC kinase hetero-complex. These data specify an antagonistic relationship between the SIN and MOR during septum formation in the filamentous ascomycete model Neurospora crassa that is, at least in part, coordinated through the GC kinase MST-1. The similarity of the SIN and MOR pathways to the animal Hippo and Ndr pathways, respectively, suggests that intensive cross-communication between distinct NDR kinase modules may also be relevant for the homologous NDR kinases of higher eukaryotes. Cytokinesis is a fundamental cellular process essential for cell proliferation of uni- and multicellular organisms. The molecular pathways that regulate cytokinesis are highly complex and involve a large number of components that form elaborate interactive networks. The fungal septation initiation network (SIN) functions as tripartite kinase cascade that connects cell cycle progression with the control of cell division. Mis-regulation of the homologous Hippo pathway in animals results in excessive proliferation and formation of tumors, underscoring the conservation and importance of these kinase networks. A second morphogenesis (MOR) pathway involves homologous components and is controlling cell polarity in fungi and higher eukaryotes. Here we show that the promiscuous functioning Ste20-related kinase MST-1 has a dual role in regulating SIN and MOR network function. Moreover, SIN and MOR coordination through MST-1 can be achieved in an enzyme-independent manner through hetero-dimerization of germinal centre kinases, providing an additional level for activity regulation of signaling networks that is not dependent on phosphate transfer. Given the functional conservation of NDR kinase signaling modules and their regulation, our work may define general mechanisms by which NDR kinase pathway are coordinated in fungi and higher eukaryotes.
Collapse
|
28
|
McCormick CD, Akamatsu MS, Ti SC, Pollard TD. Measuring affinities of fission yeast spindle pole body proteins in live cells across the cell cycle. Biophys J 2014; 105:1324-35. [PMID: 24047983 DOI: 10.1016/j.bpj.2013.08.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 08/12/2013] [Accepted: 08/14/2013] [Indexed: 12/22/2022] Open
Abstract
Characterizing protein-protein interactions is essential for understanding molecular mechanisms, although reproducing cellular conditions in vitro is challenging and some proteins are difficult to purify. We developed a method to measure binding to cellular structures using fission yeast cells as reaction vessels. We varied the concentrations of Sid2p and Mob1p (proteins of the septation initiation network) and measured their binding to spindle pole bodies (SPBs), the centrosome equivalent of yeast. From our measurements we infer that Sid2p and Mob1p both exist as monomeric, heterodimeric, and homodimeric species throughout the cell cycle. During interphase these species have widely different affinities for their common receptor Cdc11p on the SPB. The data support a model with a subset of Cdc11p binding the heterodimeric species with a Kd < 0.1 μM when Sid2p binds Mob1p-Cdc11p and Kd in the micromolar range when Mob1p binds Sid2p-Cdc11p. During mitosis an additional species presumed to be the phosphorylated Sid2p-Mob1p heterodimer binds SPBs with a lower affinity. Homodimers of Sid2p or Mob1p bind to the rest of Cdc11p at SPBs with lower affinity: Kds > 10 μM during interphase and somewhat stronger during mitosis. These measurements allowed us to account for the fluctuations in Sid2p binding to SPBs throughout the cell cycle.
Collapse
Affiliation(s)
- Chad D McCormick
- Departments of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
| | | | | | | |
Collapse
|
29
|
Muñoz S, Manjón E, García P, Sunnerhagen P, Sánchez Y. The checkpoint-dependent nuclear accumulation of Rho1p exchange factor Rgf1p is important for tolerance to chronic replication stress. Mol Biol Cell 2014; 25:1137-50. [PMID: 24478458 PMCID: PMC3967976 DOI: 10.1091/mbc.e13-11-0689] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Guanine nucleotide exchange factors control many aspects of cell morphogenesis by turning on Rho-GTPases. The fission yeast exchange factor Rgf1p (Rho gef1) specifically regulates Rho1p during polarized growth and localizes to cortical sites. Here we report that Rgf1p is relocalized to the cell nucleus during the stalled replication caused by hydroxyurea (HU). Import to the nucleus is mediated by a nuclear localization sequence at the N-terminus of Rgf1p, whereas release into the cytoplasm requires two leucine-rich nuclear export sequences at the C-terminus. Moreover, Rgf1p nuclear accumulation during replication arrest depends on the 14-3-3 chaperone Rad24p and the DNA replication checkpoint kinase Cds1p. Both proteins control the nuclear accumulation of Rgf1p by inhibition of its nuclear export. A mutant, Rgf1p-9A, that substitutes nine serine potential phosphorylation Cds1p sites for alanine fails to accumulate in the nucleus in response to replication stress, and this correlates with a severe defect in survival in the presence of HU. In conclusion, we propose that the regulation of Rgf1p could be part of the mechanism by which Cds1p and Rad24p promote survival in the presence of chronic replication stress. It will be of general interest to understand whether the same is true for homologues of Rgf1p in budding yeast and higher eukaryotes.
Collapse
Affiliation(s)
- Sofía Muñoz
- Instituto de Biología Funcional y Genómica and Departamento de Microbiología y Genética, CSIC/Universidad de Salamanca, 37008 Salamanca, Spain Department of Chemistry and Molecular Biology, Lundberg Laboratory, University of Gothenburg, S-405 30 Gothenburg, Sweden
| | | | | | | | | |
Collapse
|
30
|
Krapp A, Simanis V. Dma1-dependent degradation of Septation Initiation Network proteins during meiosis in Schizosaccharomyces pombe. J Cell Sci 2014; 127:3149-61. [DOI: 10.1242/jcs.148585] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Schizosaccharomyces pombe septation initiation network (SIN) is required for cytokinesis during vegetative growth and spore formation during meiosis. Regulation of the SIN during mitosis has been studied extensively, but less is known about its meiotic regulation. Here, we show that several aspects of the SIN regulation differ between mitosis and meiosis. First, the presence of GTP-bound spg1p is not the main determinant of the timing of cdc7p and sid1p association with the SPB during meiosis. Second, the localisation dependencies of SIN proteins differ from those in mitotic cells, suggesting a modified functional organisation of the SIN during meiosis. Third, there is stage-specific degradation of SIN components in meiosis; byr4p is degraded after meiosis I, while the degradation of cdc7p, cdc11p and sid4p occurs after the second meiotic division and depends upon the ubiquitin ligase dma1p. Finally, dma1p-dependent degradation is not restricted to the SIN, for we show that dma1p is needed for the degradation of mcp6p/hrs1p in meiosis I. Together, these data suggest that stage-specific targetted proteolysis will play an important role in regulating meiotic progression.
Collapse
|
31
|
Abstract
In Schizosaccharomyces pombe, the septation initiation network (SIN) controls cytokinetic ring (CR) formation, maintenance, and constriction. Bohnert et al. identify Cdc12 as a key CR substrate of SIN kinase Sid2. Eliminating Sid2-mediated Cdc12 phosphorylation allows multimerization of a domain that confers F-actin bundling activity, which leads to persistent Cdc12 clustering, causing CRs to collapse when cytokinesis is delayed. These findings identify a SIN-triggered oligomeric switch that modulates cytokinetic formin function, revealing a novel mechanism of actin cytoskeleton regulation during cell division. Many eukaryotes accomplish cell division by building and constricting a medial actomyosin-based cytokinetic ring (CR). In Schizosaccharomyces pombe, a Hippo-related signaling pathway termed the septation initiation network (SIN) controls CR formation, maintenance, and constriction. However, how the SIN regulates integral CR components was unknown. Here, we identify the essential cytokinetic formin Cdc12 as a key CR substrate of SIN kinase Sid2. Eliminating Sid2-mediated Cdc12 phosphorylation leads to persistent Cdc12 clustering, which prevents CR assembly in the absence of anillin-like Mid1 and causes CRs to collapse when cytokinesis is delayed. Molecularly, Sid2 phosphorylation of Cdc12 abrogates multimerization of a previously unrecognized Cdc12 domain that confers F-actin bundling activity. Taken together, our findings identify a SIN-triggered oligomeric switch that modulates cytokinetic formin function, revealing a novel mechanism of actin cytoskeleton regulation during cell division.
Collapse
|
32
|
Hsu J, Weiss EL. Cell cycle regulated interaction of a yeast Hippo kinase and its activator MO25/Hym1. PLoS One 2013; 8:e78334. [PMID: 24205201 PMCID: PMC3804511 DOI: 10.1371/journal.pone.0078334] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 09/20/2013] [Indexed: 01/12/2023] Open
Abstract
Hippo pathways are ancient signaling systems that contribute to cell growth and proliferation in a wide diversity of eukaryotes, and have emerged as a conserved regulator of organ size control in metazoans. In budding yeast, a Hippo signaling pathway called the Regulation of Ace2 and Morphogenesis (RAM) network promotes polarized cell growth and the final event in the separation of mother and daughter cells. A crucial regulatory input for RAM network control of cell separation is phosphorylation of a conserved hydrophobic motif (HM) site on the NDR/LATS family kinase Cbk1. Here we provide the first direct evidence that the Hippo-like kinase Kic1 in fact phosphorylates the HM site of Cbk1, and show that Kic1 is allosterically activated by Hym1, a highly conserved protein related to mammalian MO25. Using the structure of mammalian MO25 in complex with the Kic1-related pseudokinase STRAD, we identified conserved residues on Kic1 that are required for interaction with Hym1. We find that Kic1 and Hym1 protein levels remain constant throughout the cell cycle but the proteins’ association is regulated, with maximal interaction coinciding with peak Cbk1 HM site phosphorylation. We show that this association is necessary but not sufficient for this phosphorylation, suggesting another level of regulation is required to promote the complex to act upon its substrates. This work presents a previously undiscovered cell cycle regulated interaction between a Hippo kinase and a broadly conserved allosteric activator. Because of the conserved nature of this pathway in higher eukaryotes, this work may also provide insight into the modularity of Hippo signaling pathways.
Collapse
Affiliation(s)
- Jonathan Hsu
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
| | - Eric L. Weiss
- Department of Molecular Biosciences, Northwestern University, Evanston, Illinois, United States of America
- * E-mail:
| |
Collapse
|
33
|
Hergovich A. Regulation and functions of mammalian LATS/NDR kinases: looking beyond canonical Hippo signalling. Cell Biosci 2013; 3:32. [PMID: 23985307 PMCID: PMC3849777 DOI: 10.1186/2045-3701-3-32] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 06/30/2013] [Indexed: 02/08/2023] Open
Abstract
The metazoan Hippo pathway is an essential tumour suppressor signalling cascade that ensures normal tissue growth by co-ordinating cell proliferation, cell death and cell differentiation. Over the past years, various genetic and biochemical studies in Drosophila and mammals have defined a conserved core Hippo signalling module, composed of members of the Ste20-like kinase, the MOB co-activator and the AGC kinase families. In Drosophila, stimulated Hippo kinase phosphorylates and thereby activates the Mats/Warts complex, which consequently phosphorylates and inactivates the transcriptional co-activator Yorkie. In mammals, the counterparts of the Hippo/Mats/Warts/Yorkie cascade, namely MST1/2, MOB1A/B, LATS1/2 and YAP/TAZ, function in a similar fashion. These canonical Hippo pathways are so highly conserved that human MST2, hMOB1A and LATS1 can compensate for the loss of Hippo, Mats and Warts in flies. However, recent reports have shown that Hippo signalling is more diverse and complex, in particular in mammals. In this review, we summarize our current understanding of mammalian LATS1/2 kinases together with their closest relatives, the NDR1/2 kinases. The regulation of the LATS/NDR family of kinases will be discussed, followed by a summary of all currently known LATS/NDR substrates. Last, but not least, the biological roles of LATS/NDR kinases will be reviewed with specific emphasis on recent discoveries of canonical and non-canonical LATS/NDR functions in the extended Hippo pathway.
Collapse
Affiliation(s)
- Alexander Hergovich
- Tumour Suppressor Signalling Networks laboratory, UCL Cancer Institute, University College London, London WC1E 6BT, UK.
| |
Collapse
|
34
|
Cipak L, Gupta S, Rajovic I, Jin QW, Anrather D, Ammerer G, McCollum D, Gregan J. Crosstalk between casein kinase II and Ste20-related kinase Nak1. Cell Cycle 2013; 12:884-8. [PMID: 23462181 PMCID: PMC3637346 DOI: 10.4161/cc.24095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Although the sterile 20 (Ste20) serine/threonine protein kinase was originally identified as a component of the S. cerevisiae mating pathway, it has homologs in higher eukaryotes and is part of a larger family of Ste20-like kinases. Ste20-like kinases are involved in multiple cellular processes, such as cell growth, morphogenesis, apoptosis and immune response. Carrying out such a diverse array of biological functions requires numerous regulatory inputs and outputs in the form of protein-protein interactions and post-translational modifications. Hence, a thorough knowledge of Ste20-like kinase binding partners and phosphorylation sites will be essential for understanding the various roles of these kinases. Our recent study revealed that Schizosaccharomyces pombe Nak1 (a conserved member of the GC-kinase sub-family of Ste20-like kinases) is in a complex with the leucine-rich repeat-containing protein Sog2. Here, we show a novel and unexpected interaction between the Nak1-Sog2 kinase complex and Casein kinase 2 (Cka1, Ckb1 and Ckb2) using tandem-affinity purification followed by mass spectrometric analysis. In addition, we identify unique phosphosites on Nak1, Sog2 and the catalytic subunit of casein kinase 2, Cka1. Given the conserved nature of these kinases, we expect this work will shed light on the functions of these proteins both in yeast and higher eukaryotes.
Collapse
Affiliation(s)
- Lubos Cipak
- Max F. Perutz Laboratories, Department of Chromosome Biology, University of Vienna, Vienna, Austria
| | | | | | | | | | | | | | | |
Collapse
|