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Elkholi IE, Boulais J, Thibault MP, Phan HD, Robert A, Lai LB, Faubert D, Smith MJ, Gopalan V, Côté JF. Mapping the MOB proteins' proximity network reveals a unique interaction between human MOB3C and the RNase P complex. J Biol Chem 2023; 299:105123. [PMID: 37536630 PMCID: PMC10480535 DOI: 10.1016/j.jbc.2023.105123] [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: 05/09/2023] [Revised: 07/20/2023] [Accepted: 07/23/2023] [Indexed: 08/05/2023] Open
Abstract
Distinct functions mediated by members of the monopolar spindle-one-binder (MOB) family of proteins remain elusive beyond the evolutionarily conserved and well-established roles of MOB1 (MOB1A/B) in regulating tissue homeostasis within the Hippo pathway. Since MOB proteins are adaptors, understanding how they engage in protein-protein interactions and help assemble complexes is essential to define the full scope of their biological functions. To address this, we undertook a proximity-dependent biotin identification approach to define the interactomes of all seven human MOB proteins in HeLa and human embryonic kidney 293 cell lines. We uncovered >200 interactions, of which at least 70% are unreported on BioGrid. The generated dataset reliably recalled the bona fide interactors of the well-studied MOBs. We further defined the common and differential interactome between different MOBs on a subfamily and an individual level. We discovered a unique association between MOB3C and 7 of 10 protein subunits of the RNase P complex, an endonuclease that catalyzes tRNA 5' maturation. As a proof of principle for the robustness of the generated dataset, we validated the specific interaction of MOB3C with catalytically active RNase P by using affinity purification-mass spectrometry and pre-tRNA cleavage assays of MOB3C pulldowns. In summary, our data provide novel insights into the biology of MOB proteins and reveal the first interactors of MOB3C, components of the RNase P complex, and hence an exciting nexus with RNA biology.
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Affiliation(s)
- Islam E Elkholi
- Montreal Clinical Research Institute (IRCM), Montreal, Quebec, Canada; Molecular Biology Programs, Université de Montréal, Montreal, Quebec, Canada; Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada.
| | - Jonathan Boulais
- Montreal Clinical Research Institute (IRCM), Montreal, Quebec, Canada
| | | | - Hong-Duc Phan
- Department of Chemistry & Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Amélie Robert
- Montreal Clinical Research Institute (IRCM), Montreal, Quebec, Canada
| | - Lien B Lai
- Department of Chemistry & Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Denis Faubert
- Montreal Clinical Research Institute (IRCM), Montreal, Quebec, Canada
| | - Matthew J Smith
- Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada
| | - Venkat Gopalan
- Department of Chemistry & Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA
| | - Jean-Franҫois Côté
- Montreal Clinical Research Institute (IRCM), Montreal, Quebec, Canada; Molecular Biology Programs, Université de Montréal, Montreal, Quebec, Canada; Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada; Department of Biochemistry and Molecular Medicine, Université de Montréal, Montreal, Quebec, Canada.
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SIN-like Pathway Kinases Regulate the End of Mitosis in the Methylotrophic Yeast Ogataea polymorpha. Cells 2022; 11:cells11091519. [PMID: 35563825 PMCID: PMC9105162 DOI: 10.3390/cells11091519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 02/01/2023] Open
Abstract
The mitotic exit network (MEN) is a conserved signalling pathway essential for the termination of mitosis in the budding yeast Saccharomyces cerevisiae. All MEN components are highly conserved in the methylotrophic budding yeast Ogataea polymorpha, except for Cdc15 kinase. Instead, we identified two essential kinases OpHcd1 and OpHcd2 (homologue candidate of ScCdc15) that are homologous to SpSid1 and SpCdc7, respectively, components of the septation initiation network (SIN) of the fission yeast Schizosaccharomyces pombe. Conditional mutants for OpHCD1 and OpHCD2 exhibited significant delay in late anaphase and defective cell separation, suggesting that both genes have roles in mitotic exit and cytokinesis. Unlike Cdc15 in S. cerevisiae, the association of OpHcd1 and OpHcd2 with the yeast centrosomes (named spindle pole bodies, SPBs) is restricted to the SPB in the mother cell body. SPB localisation of OpHcd2 is regulated by the status of OpTem1 GTPase, while OpHcd1 requires the polo-like kinase OpCdc5 as well as active Tem1 to ensure the coordination of mitotic exit (ME) signalling and cell cycle progression. Our study suggests that the divergence of molecular mechanisms to control the ME-signalling pathway as well as the loss of Sid1/Hcd1 kinase in the MEN occurred relatively recently during the evolution of budding yeast.
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Cole E, Gaertig J. Anterior-posterior pattern formation in ciliates. J Eukaryot Microbiol 2022; 69:e12890. [PMID: 35075744 PMCID: PMC9309198 DOI: 10.1111/jeu.12890] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/06/2022] [Accepted: 01/17/2022] [Indexed: 11/29/2022]
Abstract
As single cells, ciliates build, duplicate, and even regenerate complex cortical patterns by largely unknown mechanisms that precisely position organelles along two cell‐wide axes: anterior–posterior and circumferential (left–right). We review our current understanding of intracellular patterning along the anterior–posterior axis in ciliates, with emphasis on how the new pattern emerges during cell division. We focus on the recent progress at the molecular level that has been driven by the discovery of genes whose mutations cause organelle positioning defects in the model ciliate Tetrahymena thermophila. These investigations have revealed a network of highly conserved kinases that are confined to either anterior or posterior domains in the cell cortex. These pattern‐regulating kinases create zones of cortical inhibition that by exclusion determine the precise placement of organelles. We discuss observations and models derived from classical microsurgical experiments in large ciliates (including Stentor) and interpret them in light of recent molecular findings in Tetrahymena. In particular, we address the involvement of intracellular gradients as vehicles for positioning organelles along the anterior‐posterior axis.
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Affiliation(s)
- Eric Cole
- Biology Department, St. Olaf College, Northfield, MN, USA
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
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4
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Vannini M, Mingione VR, Meyer A, Sniffen C, Whalen J, Seshan A. A Novel Hyperactive Nud1 Mitotic Exit Network Scaffold Causes Spindle Position Checkpoint Bypass in Budding Yeast. Cells 2021; 11:46. [PMID: 35011608 PMCID: PMC8750578 DOI: 10.3390/cells11010046] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/18/2021] [Accepted: 12/23/2021] [Indexed: 11/20/2022] Open
Abstract
Mitotic exit is a critical cell cycle transition that requires the careful coordination of nuclear positioning and cyclin B destruction in budding yeast for the maintenance of genome integrity. The mitotic exit network (MEN) is a Ras-like signal transduction pathway that promotes this process during anaphase. A crucial step in MEN activation occurs when the Dbf2-Mob1 protein kinase complex associates with the Nud1 scaffold protein at the yeast spindle pole bodies (SPBs; centrosome equivalents) and thereby becomes activated. This requires prior priming phosphorylation of Nud1 by Cdc15 at SPBs. Cdc15 activation, in turn, requires both the Tem1 GTPase and the Polo kinase Cdc5, but how Cdc15 associates with SPBs is not well understood. We have identified a hyperactive allele of NUD1, nud1-A308T, that recruits Cdc15 to SPBs in all stages of the cell cycle in a CDC5-independent manner. This allele leads to early recruitment of Dbf2-Mob1 during metaphase and requires known Cdc15 phospho-sites on Nud1. The presence of nud1-A308T leads to loss of coupling between nuclear position and mitotic exit in cells with mispositioned spindles. Our findings highlight the importance of scaffold regulation in signaling pathways to prevent improper activation.
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Affiliation(s)
- Michael Vannini
- Boston University School of Medicine, Boston, MA 02118, USA;
| | - Victoria R. Mingione
- Department of Pharmacological Sciences, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA;
| | | | - Courtney Sniffen
- Renaissance School of Medicine, Stony Brook University Hospital, Stony Brook, NY 11794, USA;
| | - Jenna Whalen
- Department of Molecular, Cell, and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605, USA;
| | - Anupama Seshan
- Department of Biology, Emmanuel College, Boston, MA 02115, USA
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Delgado ILS, Tavares A, Francisco S, Santos D, Coelho J, Basto AP, Zúquete S, Müller J, Hemphill A, Meissner M, Soares H, Leitão A, Nolasco S. Characterization of a MOB1 Homolog in the Apicomplexan Parasite Toxoplasma gondii. BIOLOGY 2021; 10:biology10121233. [PMID: 34943148 PMCID: PMC8698288 DOI: 10.3390/biology10121233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/19/2021] [Accepted: 11/23/2021] [Indexed: 01/11/2023]
Abstract
Simple Summary Monopolar spindle One Binder1 (MOB1) proteins regulate key cellular functions, namely cell multiplication and cell division. The unicellular parasite Toxoplasma gondii transitions between several morphological stages, with the need to control the number of parasites in its cellular environment. We hypothesized that MOB1 proteins could participate in the regulation of the T. gondii life cycle, having identified one MOB1 protein (TgMOB1) coded in its genome. However, this study shows that TgMOB1 presents divergent features. While in organisms studied to date the lack of MOB1 has led to cell division defects, this did not occur in T. gondii in vitro cultures where mob1 was not an essential gene. Additionally, the identification of TgMOB1 proximity interacting partners detected novel MOB1 interactors. Still, TgMOB1 localizes to the region between the new-forming nuclei during cell division, and T. gondii parasites multiply slower with TgMOB1 overexpression and faster when there is a lack of TgMOB1, indicating an intricate role for TgMOB1 in T. gondii. This study uncovers new features of the T. gondii biology, a zoonotic parasite and model organism for the phylum Apicomplexa, and highlights the complex roles MOB1 proteins may assume, with possible implications for disease processes. Abstract Monopolar spindle One Binder1 (MOB1) proteins are conserved components of the tumor-suppressing Hippo pathway, regulating cellular processes such as cytokinesis. Apicomplexan parasites present a life cycle that relies on the parasites’ ability to differentiate between stages and regulate their proliferation; thus, Hippo signaling pathways could play an important role in the regulation of the apicomplexan life cycle. Here, we report the identification of one MOB1 protein in the apicomplexan Toxoplasma gondii. To characterize the function of MOB1, we generated gain-of-function transgenic lines with a ligand-controlled destabilization domain, and loss-of-function clonal lines obtained through CRISPR/Cas9 technology. Contrary to what has been characterized in other eukaryotes, MOB1 is not essential for cytokinesis in T. gondii. However, this picture is complex since we found MOB1 localized between the newly individualized daughter nuclei at the end of mitosis. Moreover, we detected a significant delay in the replication of overexpressing tachyzoites, contrasting with increased replication rates in knockout tachyzoites. Finally, using the proximity-biotinylation method, BioID, we identified novel members of the MOB1 interactome, a probable consequence of the observed lack of conservation of some key amino acid residues. Altogether, the results point to a complex evolutionary history of MOB1 roles in apicomplexans, sharing properties with other eukaryotes but also with divergent features, possibly associated with their complex life cycle.
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Affiliation(s)
- Inês L. S. Delgado
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
- Faculdade de Medicina Veterinária, Universidade Lusófona, 1749-024 Lisboa, Portugal
| | - Alexandra Tavares
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Samuel Francisco
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Dulce Santos
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - João Coelho
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Afonso P. Basto
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Sara Zúquete
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Joachim Müller
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012 Bern, Switzerland; (J.M.); (A.H.)
| | - Andrew Hemphill
- Institute of Parasitology, Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggass-Strasse 122, CH-3012 Bern, Switzerland; (J.M.); (A.H.)
| | - Markus Meissner
- Institute for Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität Munich, D-82152 Munich, Germany;
| | - Helena Soares
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
- Centro de Química Estrutural–Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Alexandre Leitão
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
| | - Sofia Nolasco
- CIISA—Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); (A.T.); (S.F.); (D.S.); (J.C.); (A.P.B.); (S.Z.); (A.L.)
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
- Correspondence: or
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Jahan M, Iwasa H, Kuroyanagi H, Hata Y. Loss of Caenorhabditis elegans homologue of human MOB4 compromises life span, health life span and thermotolerance. Genes Cells 2021; 26:798-806. [PMID: 34428327 DOI: 10.1111/gtc.12891] [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: 07/12/2021] [Revised: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 11/29/2022]
Abstract
Mob1/phocein family proteins are conserved from yeast to mammals. Human has four MOB genes, MOB1, 2, 3 and 4. Human MOB1 protein, which is a component of the Hippo pathway, is involved in the inhibition of yes-associated protein (YAP1) through large tumor suppressor (LATS) kinases and plays a tumor suppressive role. In contrast, MOB4 activates YAP1. Caernorhabditis elegans (C. elegans) also has four MOB genes. Moreover, C. elegans has homologues of YAP1 (Ce_YAP-1) and LATS kinases (WTS-1). Nevertheless, our previous study revealed that the Hippo pathway is not conserved in C. elegans and that heat shock activates Ce_YAP-1. We also reported that Ce_YAP-1 is involved in the regulation of life span, healthy lifespan and thermotolerance. In this study, we raised a question whether and how C. elegans homologue of MOB4 (Ce_MOB-4) is involved in the regulation of Ce_YAP-1. Ce_MOB-4 is ubiquitously expressed in adult worms. This expression pattern is similar to that of Ce_YAP-1. mob-4 loss-of-function mutants show short life span, short health life span and compromise thermotolerance. However, heat shock activates Ce_YAP-1 in mob-4 mutant. In conclusion, the role of MOB4 in the activation of YAP1 is not conserved in C. elegans.
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Affiliation(s)
- Momotaj Jahan
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroaki Iwasa
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hidehito Kuroyanagi
- Department of Biochemistry, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Yutaka Hata
- Department of Medical Biochemistry, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.,Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo, Japan
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A Review of Unreduced Gametes and Neopolyploids in Alfalfa: How to Fill the Gap between Well-Established Meiotic Mutants and Next-Generation Genomic Resources. PLANTS 2021; 10:plants10050999. [PMID: 34067689 PMCID: PMC8156078 DOI: 10.3390/plants10050999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/03/2021] [Accepted: 05/12/2021] [Indexed: 01/11/2023]
Abstract
The gene flow mediated by unreduced gametes between diploid and tetraploid plants of the Medicagosativa-coerulea-falcata complex is pivotal for alfalfa breeding. Sexually tetraploidized hybrids could represent the best way to exploit progressive heterosis simultaneously derived from gene diversity, heterozygosity, and polyploidy. Moreover, unreduced gametes combined with parthenogenesis (i.e., apomixis) would enable the cloning of plants through seeds, providing a unique opportunity for the selection of superior genotypes with permanently fixed heterosis. This reproductive strategy has never been detected in the genus Medicago, but features of apomixis, such as restitutional apomeiosis and haploid parthenogenesis, have been reported. By means of an original case study, we demonstrated that sexually tetraploidized plants maintain apomeiosis, but this trait is developmentally independent from parthenogenesis. Alfalfa meiotic mutants producing unreduced egg cells revealed a null or very low capacity for parthenogenesis. The overall achievements reached so far are reviewed and discussed along with the efforts and strategies made for exploiting reproductive mutants that express apomictic elements in alfalfa breeding programs. Although several studies have investigated the cytological mechanisms responsible for 2n gamete formation and the inheritance of this trait, only a very small number of molecular markers and candidate genes putatively linked to unreduced gamete formation have been identified. Furthermore, this scenario has remained almost unchanged over the last two decades. Here, we propose a reverse genetics approach, by exploiting the genomic and transcriptomic resources available in alfalfa. Through a comparison with 9 proteins belonging to Arabidopsis thaliana known for their involvement in 2n gamete production, we identified 47 orthologous genes and evaluated their expression in several tissues, paving the way for novel candidate gene characterization studies. An overall view on strategies suitable to fill the gap between well-established meiotic mutants and next-generation genomic resources is presented and discussed.
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Chen J, Xiong Z, Miller DE, Yu Z, McCroskey S, Bradford WD, Cavanaugh AM, Jaspersen SL. The role of gene dosage in budding yeast centrosome scaling and spontaneous diploidization. PLoS Genet 2020; 16:e1008911. [PMID: 33332348 PMCID: PMC7775121 DOI: 10.1371/journal.pgen.1008911] [Citation(s) in RCA: 5] [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: 05/30/2020] [Revised: 12/31/2020] [Accepted: 11/03/2020] [Indexed: 12/12/2022] Open
Abstract
Ploidy is the number of whole sets of chromosomes in a species. Ploidy is typically a stable cellular feature that is critical for survival. Polyploidization is a route recognized to increase gene dosage, improve fitness under stressful conditions and promote evolutionary diversity. However, the mechanism of regulation and maintenance of ploidy is not well characterized. Here, we examine the spontaneous diploidization associated with mutations in components of the Saccharomyces cerevisiae centrosome, known as the spindle pole body (SPB). Although SPB mutants are associated with defects in spindle formation, we show that two copies of the mutant in a haploid yeast favors diploidization in some cases, leading us to speculate that the increased gene dosage in diploids ‘rescues’ SPB duplication defects, allowing cells to successfully propagate with a stable diploid karyotype. This copy number-based rescue is linked to SPB scaling: certain SPB subcomplexes do not scale or only minimally scale with ploidy. We hypothesize that lesions in structures with incompatible allometries such as the centrosome may drive changes such as whole genome duplication, which have shaped the evolutionary landscape of many eukaryotes. Ploidy is the number of whole sets of chromosomes in a species. Most eukaryotes alternate between a diploid (two copy) and haploid (one copy) state during their life and sexual cycle. However, as part of normal human development, specific tissues increase their DNA content. This gain of entire sets of chromosomes is known as polyploidization, and it is observed in invertebrates, plants and fungi, as well. Polyploidy is thought to improve fitness under stressful conditions and promote evolutionary diversity, but how ploidy is determined is poorly understood. Here, we use budding yeast to investigate mechanisms underlying the ploidy of wild-type cells and specific mutants that affect the centrosome, a conserved structure involved in chromosome segregation during cell division. Our work suggests that different scaling relationships (allometry) between the genome and cellular structures underlies alterations in ploidy. Furthermore, mutations in cellular structures with incompatible allometric relationships with the genome may drive genomic changes such duplications, which are underly the evolution of many species including both yeasts and humans.
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Affiliation(s)
- Jingjing Chen
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Zhiyong Xiong
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Danny E. Miller
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Zulin Yu
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Scott McCroskey
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - William D. Bradford
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Ann M. Cavanaugh
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Sue L. Jaspersen
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, United States of America
- * E-mail:
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9
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Delgado ILS, Carmona B, Nolasco S, Santos D, Leitão A, Soares H. MOB: Pivotal Conserved Proteins in Cytokinesis, Cell Architecture and Tissue Homeostasis. BIOLOGY 2020; 9:biology9120413. [PMID: 33255245 PMCID: PMC7761452 DOI: 10.3390/biology9120413] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/20/2020] [Accepted: 11/21/2020] [Indexed: 01/08/2023]
Abstract
The MOB family proteins are constituted by highly conserved eukaryote kinase signal adaptors that are often essential both for cell and organism survival. Historically, MOB family proteins have been described as kinase activators participating in Hippo and Mitotic Exit Network/ Septation Initiation Network (MEN/SIN) signaling pathways that have central roles in regulating cytokinesis, cell polarity, cell proliferation and cell fate to control organ growth and regeneration. In metazoans, MOB proteins act as central signal adaptors of the core kinase module MST1/2, LATS1/2, and NDR1/2 kinases that phosphorylate the YAP/TAZ transcriptional co-activators, effectors of the Hippo signaling pathway. More recently, MOBs have been shown to also have non-kinase partners and to be involved in cilia biology, indicating that its activity and regulation is more diverse than expected. In this review, we explore the possible ancestral role of MEN/SIN pathways on the built-in nature of a more complex and functionally expanded Hippo pathway, by focusing on the most conserved components of these pathways, the MOB proteins. We discuss the current knowledge of MOBs-regulated signaling, with emphasis on its evolutionary history and role in morphogenesis, cytokinesis, and cell polarity from unicellular to multicellular organisms.
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Affiliation(s)
- Inês L. S. Delgado
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); or (S.N.); (D.S.); (A.L.)
- Faculdade de Medicina Veterinária, Universidade Lusófona de Humanidades e Tecnologias, 1749-024 Lisboa, Portugal
| | - Bruno Carmona
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
- Centro de Química Estrutural–Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Sofia Nolasco
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); or (S.N.); (D.S.); (A.L.)
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
| | - Dulce Santos
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); or (S.N.); (D.S.); (A.L.)
| | - Alexandre Leitão
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, 1300-477 Lisboa, Portugal or (I.L.S.D.); or (S.N.); (D.S.); (A.L.)
| | - Helena Soares
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, 1990-096 Lisboa, Portugal; or
- Centro de Química Estrutural–Faculdade de Ciências da Universidade de Lisboa, 1749-016 Lisboa, Portugal
- Correspondence: or
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10
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Huang Y, Ma FT, Ren Q. Function of the MOB kinase activator-like 1 in the innate immune defense of the oriental river prawn (Macrobrachium nipponense). FISH & SHELLFISH IMMUNOLOGY 2020; 102:440-448. [PMID: 32418908 DOI: 10.1016/j.fsi.2020.04.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/25/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
The monopolar spindle one binder (MOB) protein, a key signal transducer of the Hippo signaling pathway, is involved in growth control and cancer. In this study, a new MOB kinase activator-like 1 of the oriental river prawns, Macrobrachium nipponense, (MnMOB1) was isolated and characterized. The open reading frame of MnMOB1 consisted of 651 nucleotides that encoded 216 amino acid residues and contained the Mob1_phocein domain. Phylogenetic analysis revealed that MnMOB1 clustered together with the MOB1 from Penaeus vannamei. The distribution of MnMOB1 expression in various tissues of normal prawn revealed that the MnMOB1 expression was highest in the hepatopancreas followed by those in the intestines, gill, heart, stomach, and hemocytes. In prawns challenged with Staphylococcus aureus and Vibrio parahaemolyticus, the expression levels of MnMOB1 in the hepatopancreas, gills, and intestine were upregulated. Furthermore, the expression levels of crustins and anti-lipopolysaccharide factors in prawn injected with S. aureus and V. parahaemolyticus and MnMOB1 knockdown were significantly decreased relative to those in the control group. These findings indicated that MnMOB1 is involved in the regulation of antimicrobial peptide expression and plays a crucial role in the innate immunity of M. nipponense.
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Affiliation(s)
- Ying Huang
- College of Oceanography, Hohai University, 1 Xikang Road, Nanjing, Jiangsu, 210098, China; Postdoctoral Innovation Practice Base, Jiangsu Shuixian Industrial Company Limited, 40 Tonghu Road, Baoying, Yangzhou, Jiangsu, 225800, China
| | - Fu-Tong Ma
- College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu, 210023, China
| | - Qian Ren
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, Jinan, Shandong, 250014, China; College of Marine Science and Engineering, Nanjing Normal University, 1 Wenyuan Road, Nanjing, Jiangsu, 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu, 222005, China.
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11
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Parker BW, Gogl G, Bálint M, Hetényi C, Reményi A, Weiss EL. Ndr/Lats Kinases Bind Specific Mob-Family Coactivators through a Conserved and Modular Interface. Biochemistry 2020; 59:1688-1700. [PMID: 32250593 DOI: 10.1021/acs.biochem.9b01096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Ndr/Lats kinases bind Mob coactivator proteins to form complexes that are essential and evolutionarily conserved components of "Hippo" signaling pathways, which control cell proliferation and morphogenesis in eukaryotes. All Ndr/Lats kinases have a characteristic N-terminal regulatory (NTR) region that binds a specific Mob cofactor: Lats kinases associate with Mob1 proteins, and Ndr kinases associate with Mob2 proteins. To better understand the significance of the association of Mob protein with Ndr/Lats kinases and selective binding of Ndr and Lats to distinct Mob cofactors, we determined crystal structures of Saccharomyces cerevisiae Cbk1NTR-Mob2 and Dbf2NTR-Mob1 and experimentally assessed determinants of Mob cofactor binding and specificity. This allowed a significant improvement in the previously determined structure of Cbk1 kinase bound to Mob2, presently the only crystallographic model of a full length Ndr/Lats kinase complexed with a Mob cofactor. Our analysis indicates that the Ndr/LatsNTR-Mob interface provides a distinctive kinase regulation mechanism, in which the Mob cofactor organizes the Ndr/Lats NTR to interact with the AGC kinase C-terminal hydrophobic motif (HM), which is involved in allosteric regulation. The Mob-organized NTR appears to mediate association of the HM with an allosteric site on the N-terminal kinase lobe. We also found that Cbk1 and Dbf2 associated specifically with Mob2 and Mob1, respectively. Alteration of residues in the Cbk1 NTR allows association of the noncognate Mob cofactor, indicating that cofactor specificity is restricted by discrete sites rather than being broadly distributed. Overall, our analysis provides a new picture of the functional role of Mob association and indicates that the Ndr/LatsNTR-Mob interface is largely a common structural platform that mediates kinase-cofactor binding.
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Affiliation(s)
- Benjamin W Parker
- Department of Biochemistry, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Gergo Gogl
- Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja, 1117 Budapest, Hungary.,Equipe Labellisee Ligue 2015, Department of Integrated Structural Biology, Institut de Genetique et de Biologie Moleculaire et Cellulaire (IGBMC), INSERM U1258/CNRS UMR 7104/Universite de Strasbourg, 1 rue Laurent Fries, BP 10142, F-67404 Illkirch, France
| | - Mónika Bálint
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - Csaba Hetényi
- Department of Pharmacology and Pharmacotherapy, Medical School, University of Pécs, Szigeti út 12, 7624 Pécs, Hungary
| | - Attila Reményi
- Institute of Organic Chemistry, Research Center for Natural Sciences, Magyar Tudósok körútja, 1117 Budapest, Hungary
| | - Eric L Weiss
- Molecular Biosciences, Northwestern University, Evanston, Illinois 60208, United States
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12
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Duhart JC, Raftery LA. Mob Family Proteins: Regulatory Partners in Hippo and Hippo-Like Intracellular Signaling Pathways. Front Cell Dev Biol 2020; 8:161. [PMID: 32266255 DOI: 10.3389/fcell.2020.00161/full] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 02/28/2020] [Indexed: 05/26/2023] Open
Abstract
Studies in yeast first delineated the function of Mob proteins in kinase pathways that regulate cell division and shape; in multicellular eukaryotes Mobs regulate tissue growth and morphogenesis. In animals, Mobs are adaptors in Hippo signaling, an intracellular signal-transduction pathway that restricts growth, impacting the development and homeostasis of animal organs. Central to Hippo signaling are the Nuclear Dbf2-Related (NDR) kinases, Warts and LATS1 and LATS2, in flies and mammals, respectively. A second Hippo-like signaling pathway has been uncovered in animals, which regulates cell and tissue morphogenesis. Central to this emergent pathway are the NDR kinases, Tricornered, STK38, and STK38L. In Hippo signaling, NDR kinase activation is controlled by three activating interactions with a conserved set of proteins. This review focuses on one co-activator family, the highly conserved, non-catalytic Mps1-binder-related (Mob) proteins. In this context, Mobs are allosteric activators of NDR kinases and adaptors that contribute to assembly of multiprotein NDR kinase activation complexes. In multicellular eukaryotes, the Mob family has expanded relative to model unicellular yeasts; accumulating evidence points to Mob functional diversification. A striking example comes from the most sequence-divergent class of Mobs, which are components of the highly conserved Striatin Interacting Phosphatase and Kinase (STRIPAK) complex, that antagonizes Hippo signaling. Mobs stand out for their potential to modulate the output from Hippo and Hippo-like kinases, through their roles both in activating NDR kinases and in antagonizing upstream Hippo or Hippo-like kinase activity. These opposing Mob functions suggest that they coordinate the relative activities of the Tricornered/STK38/STK38L and Warts/LATS kinases, and thus have potential to assemble nodes for pathway signaling output. We survey the different facets of Mob-dependent regulation of Hippo and Hippo-like signaling and highlight open questions that hinge on unresolved aspects of Mob functions.
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Affiliation(s)
- Juan Carlos Duhart
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Laurel A Raftery
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
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13
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Duhart JC, Raftery LA. Mob Family Proteins: Regulatory Partners in Hippo and Hippo-Like Intracellular Signaling Pathways. Front Cell Dev Biol 2020; 8:161. [PMID: 32266255 PMCID: PMC7096357 DOI: 10.3389/fcell.2020.00161] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 02/28/2020] [Indexed: 12/16/2022] Open
Abstract
Studies in yeast first delineated the function of Mob proteins in kinase pathways that regulate cell division and shape; in multicellular eukaryotes Mobs regulate tissue growth and morphogenesis. In animals, Mobs are adaptors in Hippo signaling, an intracellular signal-transduction pathway that restricts growth, impacting the development and homeostasis of animal organs. Central to Hippo signaling are the Nuclear Dbf2-Related (NDR) kinases, Warts and LATS1 and LATS2, in flies and mammals, respectively. A second Hippo-like signaling pathway has been uncovered in animals, which regulates cell and tissue morphogenesis. Central to this emergent pathway are the NDR kinases, Tricornered, STK38, and STK38L. In Hippo signaling, NDR kinase activation is controlled by three activating interactions with a conserved set of proteins. This review focuses on one co-activator family, the highly conserved, non-catalytic Mps1-binder-related (Mob) proteins. In this context, Mobs are allosteric activators of NDR kinases and adaptors that contribute to assembly of multiprotein NDR kinase activation complexes. In multicellular eukaryotes, the Mob family has expanded relative to model unicellular yeasts; accumulating evidence points to Mob functional diversification. A striking example comes from the most sequence-divergent class of Mobs, which are components of the highly conserved Striatin Interacting Phosphatase and Kinase (STRIPAK) complex, that antagonizes Hippo signaling. Mobs stand out for their potential to modulate the output from Hippo and Hippo-like kinases, through their roles both in activating NDR kinases and in antagonizing upstream Hippo or Hippo-like kinase activity. These opposing Mob functions suggest that they coordinate the relative activities of the Tricornered/STK38/STK38L and Warts/LATS kinases, and thus have potential to assemble nodes for pathway signaling output. We survey the different facets of Mob-dependent regulation of Hippo and Hippo-like signaling and highlight open questions that hinge on unresolved aspects of Mob functions.
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Affiliation(s)
| | - Laurel A. Raftery
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
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14
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Guo Z, Yue X, Cui X, Song L, Cheng Y. AtMOB1 Genes Regulate Jasmonate Accumulation and Plant Development. PLANT PHYSIOLOGY 2020; 182:1481-1493. [PMID: 31862839 PMCID: PMC7054864 DOI: 10.1104/pp.19.01434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
The MOB1 proteins are highly conserved in yeasts, animals, and plants. Previously, we showed that the Arabidopsis (Arabidopsis thaliana) MOB1A gene (AtMOB1A/NCP1) plays critical roles in auxin-mediated plant development. Here, we report that AtMOB1A and AtMOB1B redundantly and negatively regulate jasmonate (JA) accumulation and function in Arabidopsis development. The two MOB1 genes exhibited similar expression patterns, and the MOB1 proteins displayed similar subcellular localizations and physically interacted in vivo. Furthermore, the atmob1a atmob1b (mob1a/1b) double mutant displayed severe developmental defects, which were much stronger than those of either single mutant. Interestingly, many JA-related genes were up-regulated in mob1a/1b, suggesting that AtMOB1A and AtMOB1B negatively regulate the JA pathways. mob1a/1b plants accumulated more JA and were hypersensitive to exogenous JA treatments. Disruption of MYC2, a key gene in JA signaling, in the mob1a/1b background partially alleviated the root defects and JA hypersensitivity observed in mob1a/1b. Moreover, the expression levels of the MYC2-repressed genes PLT1 and PLT2 were significantly decreased in the mob1a/1b double mutant. Our results showed that MOB1A/1B genetically interact with SIK1 and antagonistically modulate JA-related gene expression. Taken together, our findings indicate that AtMOB1A and AtMOB1B play important roles in regulating JA accumulation and Arabidopsis development.
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Affiliation(s)
- Zhiai Guo
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Xiaozhen Yue
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaona Cui
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lizhen Song
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Youfa Cheng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
- Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100101, China
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15
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Bae JS, Kim SM, Jeon Y, Sim J, Jang JY, Son J, Hong W, Park MK, Lee H. Loss of Mob1a/b impairs the differentiation of mouse embryonic stem cells into the three germ layer lineages. Exp Mol Med 2019; 51:1-12. [PMID: 31723125 PMCID: PMC6853965 DOI: 10.1038/s12276-019-0342-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 06/24/2019] [Accepted: 09/19/2019] [Indexed: 01/05/2023] Open
Abstract
The Hippo pathway plays a crucial role in cell proliferation and apoptosis and can regulate stem cell maintenance and embryonic development. MOB kinase activators 1A and 1B (Mob1a/b) are key components of the Hippo pathway, whose homozygous deletion in mice causes early embryonic lethality at the preimplantation stage. To investigate the role of Mob1a/b in stem cell maintenance and differentiation, an embryonic stem cell (ESC) clone in which Mob1a/b could be conditionally depleted was generated and characterized. Although Mob1a/b depletion did not affect the stemness or proliferation of mouse ESCs, this depletion caused defects in differentiation into the three germ layers. Yap knockdown rescued the in vitro and in vivo defects in differentiation caused by Mob1a/b depletion, suggesting that differentiation defects caused by Mob1a/b depletion were Yap-dependent. In teratoma experiments, Yap knockdown in Mob1a/b-depleted ESCs partially restored defects in differentiation, indicating that hyperactivation of Taz, another effector of the Hippo pathway, inhibited differentiation into the three germ layers. Taken together, these results suggest that Mob1a/b or Hippo signaling plays a critical role in the differentiation of mouse ESCs into the three germ layers, which is dependent on Yap. These close relationship of the Hippo pathway with the differentiation of stem cells supports its potential as a therapeutic target in regenerative medicine.
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Affiliation(s)
- June Sung Bae
- Research Institute, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea
| | - Sun Mi Kim
- Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea
| | - Yoon Jeon
- Research Institute, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea
| | - Juyeon Sim
- Research Institute, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea
| | - Ji Yun Jang
- Research Institute, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea
| | - Jaehyung Son
- Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea
| | - Woosol Hong
- Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea
| | - Mi Kyung Park
- Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea
| | - Ho Lee
- Research Institute, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea. .,Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Gyeonggi, 10408, Republic of Korea.
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16
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Gundogdu R, Hergovich A. MOB (Mps one Binder) Proteins in the Hippo Pathway and Cancer. Cells 2019; 8:cells8060569. [PMID: 31185650 PMCID: PMC6627106 DOI: 10.3390/cells8060569] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 12/22/2022] Open
Abstract
The family of MOBs (monopolar spindle-one-binder proteins) is highly conserved in the eukaryotic kingdom. MOBs represent globular scaffold proteins without any known enzymatic activities. They can act as signal transducers in essential intracellular pathways. MOBs have diverse cancer-associated cellular functions through regulatory interactions with members of the NDR/LATS kinase family. By forming additional complexes with serine/threonine protein kinases of the germinal centre kinase families, other enzymes and scaffolding factors, MOBs appear to be linked to an even broader disease spectrum. Here, we review our current understanding of this emerging protein family, with emphases on post-translational modifications, protein-protein interactions, and cellular processes that are possibly linked to cancer and other diseases. In particular, we summarise the roles of MOBs as core components of the Hippo tissue growth and regeneration pathway.
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Affiliation(s)
- Ramazan Gundogdu
- Vocational School of Health Services, Bingol University, 12000 Bingol, Turkey.
| | - Alexander Hergovich
- UCL Cancer Institute, University College London, WC1E 6BT, London, United Kingdom.
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17
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Two Antagonistic Hippo Signaling Circuits Set the Division Plane at the Medial Position in the Ciliate Tetrahymena. Genetics 2018; 211:651-663. [PMID: 30593491 DOI: 10.1534/genetics.118.301889] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 12/21/2018] [Indexed: 12/17/2022] Open
Abstract
In a single cell, ciliates maintain a complex pattern of cortical organelles that are arranged along the anteroposterior and circumferential axes. The underlying molecular mechanisms of intracellular pattern formation in ciliates are largely unknown. Ciliates divide by tandem duplication, a process that remodels the parental cell into two daughters aligned head-to-tail. In the elo1-1 mutant of Tetrahymena thermophila, the segmentation boundary/division plane forms too close to the posterior end of the parental cell, producing a large anterior and a small posterior daughter cell, respectively. We show that ELO1 encodes a Lats/NDR kinase that marks the posterior segment of the cell cortex, where the division plane does not form in the wild-type. Elo1 acts independently of CdaI, a Hippo/Mst kinase that marks the anterior half of the parental cell, and whose loss shifts the division plane anteriorly. We propose that, in Tetrahymena, two antagonistic Hippo circuits focus the segmentation boundary/division plane at the equatorial position, by excluding divisional morphogenesis from the cortical areas that are too close to cell ends.
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18
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Song Z, Han X, Zou H, Zhang B, Ding Y, Xu X, Zeng J, Liu J, Gong A. PTEN-GSK3β-MOB1 axis controls neurite outgrowth in vitro and in vivo. Cell Mol Life Sci 2018; 75:4445-4464. [PMID: 30069702 PMCID: PMC11105474 DOI: 10.1007/s00018-018-2890-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 07/23/2018] [Accepted: 07/25/2018] [Indexed: 12/14/2022]
Abstract
Mps One binder 1 (MOB1) is a core component of NDR/LATS kinase and a positive regulator of the Hippo signaling pathway. However, its role in neurite outgrowth still remains to be clarified. Here, we confirmed, for the first time, that MOB1 promoted neurite outgrowth and was involved in functional recovery after spinal cord injury (SCI) in mice. Mechanistically, we found that MOB1 stability was regulated by the PTEN-GSK3β axis. The MOB1 protein was significantly up-regulated in PTEN-knockdown neuronal cells. This effect was dependent on the lipid phosphatase activity of PTEN. Moreover, MOB1 was found to be a novel substrate for GSK3β that is phosphorylated on serine 146 and degraded via the ubiquitin-proteasome system (UPS). Finally, in vivo lentiviral-mediated silencing of PTEN promoted neurite outgrowth and functional recovery after SCI and this effect was reversed by down-regulation of MOB1. Taken together, this study provided mechanistic insight into how MOB1 acts as a novel and a necessary regulator in PTEN-GSK3β axis that controls neurite outgrowth after SCI.
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Affiliation(s)
- Zhiwen Song
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China
| | - Xiu Han
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Hongjun Zou
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China
| | - Bin Zhang
- Department of Laboratory Medicine, Affiliated Hospital of Jining Medical University, Jining, 272000, China
| | - Ya Ding
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China
| | - Xu Xu
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China
| | - Jian Zeng
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Jinbo Liu
- Department of Orthopaedics, School of Medicine, The Third Affiliated Hospital of Soochow University, Changzhou, 213000, China.
| | - Aihua Gong
- Department of Cell Biology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China.
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19
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Budding Yeast BFA1 Has Multiple Positive Roles in Directing Late Mitotic Events. G3-GENES GENOMES GENETICS 2018; 8:3397-3410. [PMID: 30166350 PMCID: PMC6222586 DOI: 10.1534/g3.118.200672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The proper regulation of cell cycle transitions is paramount to the maintenance of cellular genome integrity. In Saccharomyces cerevisiae, the mitotic exit network (MEN) is a Ras-like signaling cascade that effects the transition from M phase to G1 during the cell division cycle in budding yeast. MEN activation is tightly regulated. It occurs during anaphase and is coupled to mitotic spindle position by the spindle position checkpoint (SPoC). Bfa1 is a key component of the SPoC and functions as part of a two-component GAP complex along with Bub2 The GAP activity of Bfa1-Bub2 keeps the MEN GTPase Tem1 inactive in cells with mispositioned spindles, thereby preventing inappropriate mitotic exit and preserving genome integrity. Interestingly, a GAP-independent role for Bfa1 in mitotic exit regulation has been previously identified. However the nature of this Bub2-independent role and its biological significance are not understood. Here we show that Bfa1 also activates the MEN by promoting the localization of Tem1 primarily to the daughter spindle pole body (dSPB). We demonstrate that the overexpression of BFA1 is lethal due to defects in Tem1 localization, which is required for its activity. In addition, our studies demonstrate a Tem1-independent role for Bfa1 in promoting proper cytokinesis. Cells lacking TEM1, in which the essential mitotic exit function is bypassed, exhibit cytokinesis defects. These defects are suppressed by the overexpression of BFA1 We conclude that Bfa1 functions to both inhibit and activate late mitotic events.
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20
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Vitulo N, Vezzi A, Galla G, Citterio S, Marino G, Ruperti B, Zermiani M, Albertini E, Valle G, Barcaccia G. Characterization and Evolution of the Cell Cycle-Associated Mob Domain-Containing Proteins in Eukaryotes. Evol Bioinform Online 2017. [DOI: 10.1177/117693430700300007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The MOB family includes a group of cell cycle-associated proteins highly conserved throughout eukaryotes, whose founding members are implicated in mitotic exit and co-ordination of cell cycle progression with cell polarity and morphogenesis. Here we report the characterization and evolution of the MOB domain-containing proteins as inferred from the 43 eukaryotic genomes so far sequenced. We show that genes for Mob-like proteins are present in at least 41 of these genomes, confirming the universal distribution of this protein family and suggesting its prominent biological function. The phylogenetic analysis reveals five distinct MOB domain classes, showing a progressive expansion of this family from unicellular to multicellular organisms, reaching the highest number in mammals. Plant Mob genes appear to have evolved from a single ancestor, most likely after the loss of one or more genes during the early stage of Viridiplantae evolutionary history. Three of the Mob classes are widespread among most of the analyzed organisms. The possible biological and molecular function of Mob proteins and their role in conserved signaling pathways related to cell proliferation, cell death and cell polarity are also presented and critically discussed.
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Affiliation(s)
- Nicola Vitulo
- Dipartimento di Biologia, University of Padova, Viale G. Colombo 3, 35121, Padova
| | - Alessandro Vezzi
- Dipartimento di Biologia, University of Padova, Viale G. Colombo 3, 35121, Padova
| | - Giulio Galla
- Dipartimento di Agronomia Ambientale e Produzioni Vegetali, University of Padova - Agripolis, Viale dell'Università 16, 35020, Legnaro, Padova, Italy
| | - Sandra Citterio
- Dipartimento di Scienze dell'Ambiente e del Territorio, University of Milano - Bicocca, Piazza della Scienza 1, 20126, Milano, Italy
| | - Giada Marino
- Dipartimento di Scienze dell'Ambiente e del Territorio, University of Milano - Bicocca, Piazza della Scienza 1, 20126, Milano, Italy
| | - Benedetto Ruperti
- Dipartimento di Scienze Agrarie e Ambientali, University of Udine, Via delle Scienze 208, 33100, Udine, Italy
| | - Monica Zermiani
- Dipartimento di Scienze Agrarie e Ambientali, University of Udine, Via delle Scienze 208, 33100, Udine, Italy
| | - Emidio Albertini
- Dipartimento di Biologia Vegetale e Biotecnologie Agroambientali e Zootecniche, Borgo XX Giugno, 06121, Perugia, Italy
| | - Giorgio Valle
- Dipartimento di Biologia, University of Padova, Viale G. Colombo 3, 35121, Padova
| | - Gianni Barcaccia
- Dipartimento di Agronomia Ambientale e Produzioni Vegetali, University of Padova - Agripolis, Viale dell'Università 16, 35020, Legnaro, Padova, Italy
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21
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Jiang YY, Maier W, Baumeister R, Minevich G, Joachimiak E, Ruan Z, Kannan N, Clarke D, Frankel J, Gaertig J. The Hippo Pathway Maintains the Equatorial Division Plane in the Ciliate Tetrahymena. Genetics 2017; 206:873-888. [PMID: 28413159 PMCID: PMC5499192 DOI: 10.1534/genetics.117.200766] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/29/2017] [Indexed: 12/30/2022] Open
Abstract
The mechanisms that govern pattern formation within the cell are poorly understood. Ciliates carry on their surface an elaborate pattern of cortical organelles that are arranged along the anteroposterior and circumferential axes by largely unknown mechanisms. Ciliates divide by tandem duplication: the cortex of the predivision cell is remodeled into two similarly sized and complete daughters. In the conditional cdaI-1 mutant of Tetrahymena thermophila, the division plane migrates from its initially correct equatorial position toward the cell's anterior, resulting in unequal cell division, and defects in nuclear divisions and cytokinesis. We used comparative whole genome sequencing to identify the cause of cdaI-1 as a mutation in a Hippo/Mst kinase. CdaI is a cortical protein with a cell cycle-dependent, highly polarized localization. Early in cell division, CdaI marks the anterior half of the cell, and later concentrates at the posterior end of the emerging anterior daughter. Despite the strong association of CdaI with the new posterior cell end, the cdaI-1 mutation does not affect the patterning of the new posterior cortical organelles. We conclude that, in Tetrahymena, the Hippo pathway maintains an equatorial position of the fission zone, and, by this activity, specifies the relative dimensions of the anterior and posterior daughter cell.
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Affiliation(s)
- Yu-Yang Jiang
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | - Wolfgang Maier
- Bio3/Bioinformatics and Molecular Genetics (Faculty of Biology) and ZMBZ (Faculty of Medicine)
| | - Ralf Baumeister
- Bio3/Bioinformatics and Molecular Genetics (Faculty of Biology) and ZMBZ (Faculty of Medicine)
- Centre for Biological Signalling Studies (BIOSS), Albert-Ludwigs-University of Freiburg, 79104 Germany
| | - Gregory Minevich
- Department of Biochemistry and Molecular Biophysics, Columbia University Medical Center, New York, New York 10032
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - Zheng Ruan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602
| | - Diamond Clarke
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
| | - Joseph Frankel
- Department of Biology, University of Iowa, Iowa City, Iowa 52242
| | - Jacek Gaertig
- Department of Cellular Biology, University of Georgia, Athens, Georgia 30602
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22
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Nakatani K, Maehama T, Nishio M, Goto H, Kato W, Omori H, Miyachi Y, Togashi H, Shimono Y, Suzuki A. Targeting the Hippo signalling pathway for cancer treatment. J Biochem 2017; 161:237-244. [PMID: 28003431 DOI: 10.1093/jb/mvw074] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/06/2016] [Indexed: 12/14/2022] Open
Abstract
The Hippo signalling pathway monitors cell-cell contact and external factors that shape tissue structure. In mice, tumourigenesis and developmental abnormalities are common consequences of dysregulated Hippo signalling. Expression of Hippo pathway components is also frequently altered in human tumours and correlates with poor prognosis and reduced patient survival. Thus, the Hippo pathway is an attractive anti-cancer target. Here, we provide an overview of the function and regulation of Hippo signalling components and summarize progress to date on the development of agents able to regulate Hippo signalling for cancer therapy.
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Affiliation(s)
- Keisuke Nakatani
- Division of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.,Division of Cancer Genetics, Medical Institute of Bioregulation Kyushu University, Fukuoka, Japan
| | - Tomohiko Maehama
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Miki Nishio
- Division of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.,Division of Cancer Genetics, Medical Institute of Bioregulation Kyushu University, Fukuoka, Japan
| | - Hiroki Goto
- Division of Cancer Genetics, Medical Institute of Bioregulation Kyushu University, Fukuoka, Japan
| | - Wakako Kato
- Division of Cancer Genetics, Medical Institute of Bioregulation Kyushu University, Fukuoka, Japan
| | - Hirofumi Omori
- Division of Cancer Genetics, Medical Institute of Bioregulation Kyushu University, Fukuoka, Japan
| | - Yosuke Miyachi
- Division of Cancer Genetics, Medical Institute of Bioregulation Kyushu University, Fukuoka, Japan
| | - Hideru Togashi
- Division of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Yohei Shimono
- Division of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Akira Suzuki
- Division of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.,Division of Cancer Genetics, Medical Institute of Bioregulation Kyushu University, Fukuoka, Japan
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23
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The Mitotic Exit Network Regulates Spindle Pole Body Selection During Sporulation of Saccharomyces cerevisiae. Genetics 2017; 206:919-937. [PMID: 28450458 DOI: 10.1534/genetics.116.194522] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 04/11/2017] [Indexed: 01/11/2023] Open
Abstract
Age-based inheritance of centrosomes in eukaryotic cells is associated with faithful chromosome distribution in asymmetric cell divisions. During Saccharomyces cerevisiae ascospore formation, such an inheritance mechanism targets the yeast centrosome equivalents, the spindle pole bodies (SPBs) at meiosis II onset. Decreased nutrient availability causes initiation of spore formation at only the younger SPBs and their associated genomes. This mechanism ensures encapsulation of nonsister genomes, which preserves genetic diversity and provides a fitness advantage at the population level. Here, by usage of an enhanced system for sporulation-induced protein depletion, we demonstrate that the core mitotic exit network (MEN) is involved in age-based SPB selection. Moreover, efficient genome inheritance requires Dbf2/20-Mob1 during a late step in spore maturation. We provide evidence that the meiotic functions of the MEN are more complex than previously thought. In contrast to mitosis, completion of the meiotic divisions does not strictly rely on the MEN whereas its activity is required at different time points during spore development. This is reminiscent of vegetative MEN functions in spindle polarity establishment, mitotic exit, and cytokinesis. In summary, our investigation contributes to the understanding of age-based SPB inheritance during sporulation of S. cerevisiae and provides general insights on network plasticity in the context of a specialized developmental program. Moreover, the improved system for a developmental-specific tool to induce protein depletion will be useful in other biological contexts.
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24
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Xiong S, Couzens AL, Kean MJ, Mao DY, Guettler S, Kurinov I, Gingras AC, Sicheri F. Regulation of Protein Interactions by Mps One Binder (MOB1) Phosphorylation. Mol Cell Proteomics 2017; 16:1111-1125. [PMID: 28373297 DOI: 10.1074/mcp.m117.068130] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/27/2017] [Indexed: 12/22/2022] Open
Abstract
MOB1 is a multifunctional protein best characterized for its integrative role in regulating Hippo and NDR pathway signaling in metazoans and the Mitotic Exit Network in yeast. Human MOB1 binds both the upstream kinases MST1 and MST2 and the downstream AGC group kinases LATS1, LATS2, NDR1, and NDR2. Binding of MOB1 to MST1 and MST2 is mediated by its phosphopeptide-binding infrastructure, the specificity of which matches the phosphorylation consensus of MST1 and MST2. On the other hand, binding of MOB1 to the LATS and NDR kinases is mediated by a distinct interaction surface on MOB1. By assembling both upstream and downstream kinases into a single complex, MOB1 facilitates the activation of the latter by the former through a trans-phosphorylation event. Binding of MOB1 to its upstream partners also renders MOB1 a substrate, which serves to differentially regulate its two protein interaction activities (at least in vitro). Our previous interaction proteomics analysis revealed that beyond associating with MST1 (and MST2), MOB1A and MOB1B can associate in a phosphorylation-dependent manner with at least two other signaling complexes, one containing the Rho guanine exchange factors (DOCK6-8) and the other containing the serine/threonine phosphatase PP6. Whether these complexes are recruited through the same mode of interaction as MST1 and MST2 remains unknown. Here, through a comprehensive set of biochemical, biophysical, mutational and structural studies, we quantitatively assess how phosphorylation of MOB1A regulates its interaction with both MST kinases and LATS/NDR family kinases in vitro Using interaction proteomics, we validate the significance of our in vitro studies and also discover that the phosphorylation-dependent recruitment of PP6 phosphatase and Rho guanine exchange factor protein complexes differ in key respects from that elucidated for MST1 and MST2. Together our studies confirm and extend previous work to delineate the intricate regulatory steps in key signaling pathways.
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Affiliation(s)
- Shawn Xiong
- From the ‡Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada, M5G 1X5.,§Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
| | - Amber L Couzens
- From the ‡Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada, M5G 1X5
| | - Michelle J Kean
- From the ‡Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada, M5G 1X5
| | - Daniel Y Mao
- From the ‡Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada, M5G 1X5
| | - Sebastian Guettler
- From the ‡Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada, M5G 1X5.,¶The Institute of Cancer Research, Divisions of Structural Biology and Cancer Biology, London, UK, SW7 3RP
| | - Igor Kurinov
- ‖NE-CAT APS, Building 436E, Argonne National Lab, 9700 S. Cass Avenue, Argonne, Illinois 60439
| | - Anne-Claude Gingras
- From the ‡Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada, M5G 1X5; .,**Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
| | - Frank Sicheri
- From the ‡Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada, M5G 1X5; .,§Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada, M5S 1A8.,**Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
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25
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Schmidpeter J, Dahl M, Hofmann J, Koch C. ChMob2 binds to ChCbk1 and promotes virulence and conidiation of the fungal pathogen Colletotrichum higginsianum. BMC Microbiol 2017; 17:22. [PMID: 28103800 PMCID: PMC5248491 DOI: 10.1186/s12866-017-0932-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/12/2017] [Indexed: 01/11/2023] Open
Abstract
Background Mob family proteins are conserved between animals, plants and fungi and are essential for the activation of NDR kinases that control crucial cellular processes like cytokinesis, proliferation and morphology. Results We identified a hypomorphic allele of ChMOB2 in a random insertional mutant (vir-88) of the hemibiotrophic ascomycete fungus Colletotrichum higginsianum. The mutant is impaired in conidiation, host penetration and virulence on Arabidopsis thaliana. ChMob2 binds to and co-localizes with the NDR/LATS kinase homolog ChCbk1. Mutants in the two potential ChCbk1 downstream targets ChSSD1 and ChACE2 show defects in pathogenicity. The genome of C. higginsianum encodes two more Mob proteins. While we could not detect any effect on pathogenicity in ΔChmob3 mutants, ChMob1 is involved in conidiation, septae formation and virulence. Conclusion This study shows that ChMob2 binds to the conserved NDR/LATS Kinase ChCbk1 and plays an important role in pathogenicity of Colletotrichum higginsianum on Arabidopsis thaliana. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-0932-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Johannes Schmidpeter
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Marlis Dahl
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Jörg Hofmann
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany
| | - Christian Koch
- Department of Biology, Division of Biochemistry, Friedrich-Alexander University Erlangen-Nuremberg, Staudtstrasse 5, 91058, Erlangen, Germany.
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26
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Saputo S, Norman KL, Murante T, Horton BN, Diaz JDLC, DiDone L, Colquhoun J, Schroeder JW, Simmons LA, Kumar A, Krysan DJ. Complex Haploinsufficiency-Based Genetic Analysis of the NDR/Lats Kinase Cbk1 Provides Insight into Its Multiple Functions in Candida albicans. Genetics 2016; 203:1217-33. [PMID: 27206715 PMCID: PMC4937472 DOI: 10.1534/genetics.116.188029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/11/2016] [Indexed: 01/11/2023] Open
Abstract
Although the analysis of genetic interactions and networks is a powerful approach to understanding biology, it has not been applied widely to the pathogenic yeast Candida albicans Here, we describe the use of both screening and directed genetic interaction studies based on complex haploinsufficiency to probe the function of the R: egulation of A: ce2 and M: orphogenesis (RAM) pathway in C. albicans A library of 5200 Tn7-mutagenized derivatives of a parental strain heterozygous at CBK1, the key kinase in the RAM pathway, was screened for alterations in serum-induced filamentation. Following confirmation of phenotypes and identification of insertion sites by sequencing, a set of 36 unique double heterozygous strains showing complex haploinsufficiency was obtained. In addition to a large set of genes regulated by the RAM transcription factor Ace2, genes related to cell wall biosynthesis, cell cycle, polarity, oxidative stress, and nitrogen utilization were identified. Follow-up analysis led to the first demonstration that the RAM pathway is required for oxidative stress tolerance in a manner related to the two-component-regulated kinase Chk1 and revealed a potential direct connection between the RAM pathway and the essential Mps1 spindle pole-related kinase. In addition, genetic interactions with CDC42-related genes MSB1, a putative scaffold protein, and RGD3, a putative Rho GTPase-activating protein (GAP) were identified. We also provide evidence that Rgd3 is a GAP for Cdc42 and show that its localization and phosphorylation are dependent on Cbk1.
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Affiliation(s)
- Sarah Saputo
- Department of Microbiology/Immunology University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Kaitlyn L Norman
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Thomas Murante
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Brooke N Horton
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Jacinto De La Cruz Diaz
- Department of Microbiology/Immunology University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Louis DiDone
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Jennifer Colquhoun
- Department of Microbiology/Immunology University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Jeremy W Schroeder
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Lyle A Simmons
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Anuj Kumar
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109
| | - Damian J Krysan
- Department of Microbiology/Immunology University of Rochester School of Medicine and Dentistry, Rochester, New York 14642 Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
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27
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Structural basis for autoinhibition and its relief of MOB1 in the Hippo pathway. Sci Rep 2016; 6:28488. [PMID: 27335147 PMCID: PMC4917820 DOI: 10.1038/srep28488] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 06/03/2016] [Indexed: 01/07/2023] Open
Abstract
MOB1 protein is a key regulator of large tumor suppressor 1/2 (LATS1/2) kinases in the Hippo pathway. MOB1 is present in an autoinhibited form and is activated by MST1/2-mediated phosphorylation, although the precise mechanisms responsible for autoinhibition and activation are unknown due to lack of an autoinhibited MOB1 structure. Here, we report on the crystal structure of full-length MOB1B in the autoinhibited form and a complex between the MOB1B core domain and the N-terminal regulation (NTR) domain of LATS1. The structure of full-length MOB1B shows that the N-terminal extension forms a short β-strand, the SN strand, followed by a long conformationally flexible positively-charged linker and α-helix, the Switch helix, which blocks the LATS1 binding surface of MOB1B. The Switch helix is stabilized by β-sheet formation of the SN strand with the S2 strand of the MOB1 core domain. Phosphorylation of Thr12 and Thr35 residues structurally accelerates dissociation of the Switch helix from the LATS1-binding surface by the "pull-the-string" mechanism, thereby enabling LATS1 binding.
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28
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Cui X, Guo Z, Song L, Wang Y, Cheng Y. NCP1/AtMOB1A Plays Key Roles in Auxin-Mediated Arabidopsis Development. PLoS Genet 2016; 12:e1005923. [PMID: 26942722 PMCID: PMC4778850 DOI: 10.1371/journal.pgen.1005923] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 02/16/2016] [Indexed: 12/31/2022] Open
Abstract
MOB1 protein is a core component of the Hippo signaling pathway in animals where it is involved in controlling tissue growth and tumor suppression. Plant MOB1 proteins display high sequence homology to animal MOB1 proteins, but little is known regarding their role in plant growth and development. Herein we report the critical roles of Arabidopsis MOB1 (AtMOB1A) in auxin-mediated development in Arabidopsis. We found that loss-of-function mutations in AtMOB1A completely eliminated the formation of cotyledons when combined with mutations in PINOID (PID), which encodes a Ser/Thr protein kinase that participates in auxin signaling and transport. We showed that atmob1a was fully rescued by its Drosophila counterpart, suggesting functional conservation. The atmob1a pid double mutants phenocopied several well-characterized mutant combinations that are defective in auxin biosynthesis or transport. Moreover, we demonstrated that atmob1a greatly enhanced several other known auxin mutants, suggesting that AtMOB1A plays a key role in auxin-mediated plant development. The atmob1a single mutant displayed defects in early embryogenesis and had shorter root and smaller flowers than wild type plants. AtMOB1A is uniformly expressed in embryos and suspensor cells during embryogenesis, consistent with its role in embryo development. AtMOB1A protein is localized to nucleus, cytoplasm, and associated to plasma membrane, suggesting that it plays roles in these subcellular localizations. Furthermore, we showed that disruption of AtMOB1A led to a reduced sensitivity to exogenous auxin. Our results demonstrated that AtMOB1A plays an important role in Arabidopsis development by promoting auxin signaling. MOB1 protein is a key component of the Hippo signaling pathway in animals, and it plays critical roles in organ size control. The plant hormone auxin regulates many aspects of plant growth and development including organogenesis. In this work, we showed that AtMOB1A, which is highly homologous to animal MOB1 proteins, plays an important role in plant organogenesis. Furthermore, we demonstrated that AtMOB1A synergistically interacts with auxin biosynthesis, transport, and signaling pathways to regulate Arabidopsis development. We further showed that AtMOB1A likely controls plant development by promoting auxin signaling. This work identified a new player in auxin-mediated plant development and lays a foundation for further dissection of the mechanisms by which auxin regulates organogenesis.
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Affiliation(s)
- Xiaona Cui
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Zhiai Guo
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Lizhen Song
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Yanli Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Youfa Cheng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
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29
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Miller DP, Hall H, Chaparian R, Mara M, Mueller A, Hall MC, Shannon KB. Dephosphorylation of Iqg1 by Cdc14 regulates cytokinesis in budding yeast. Mol Biol Cell 2015; 26:2913-26. [PMID: 26085509 PMCID: PMC4571329 DOI: 10.1091/mbc.e14-12-1637] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 06/08/2015] [Accepted: 06/09/2015] [Indexed: 01/11/2023] Open
Abstract
Cytokinesis separates cells by contraction of a ring composed of filamentous actin (F-actin) and type II myosin. Iqg1, an IQGAP family member, is an essential protein in Saccharomyces cerevisiae required for assembly and contraction of the actomyosin ring. Localization of F-actin to the ring occurs only after anaphase and is mediated by the calponin homology domain (CHD) of Iqg1, but the regulatory mechanisms that temporally restrict actin ring assembly are not well defined. We tested the hypothesis that dephosphorylation of four perfect cyclin-dependent kinase (Cdk) sites flanking the CHD promotes actin ring formation, using site-specific alanine mutants. Cells expressing the nonphosphorylatable iqg1-4A allele formed actin rings before anaphase and exhibited defects in myosin contraction and cytokinesis. The Cdc14 phosphatase is required for normal cytokinesis and acts on specific Cdk phosphorylation sites. Overexpression of Cdc14 resulted in premature actin ring assembly, whereas inhibition of Cdc14 function prevented actin ring formation. Cdc14 associated with Iqg1, dependent on several CHD-flanking Cdk sites, and efficiently dephosphorylated these sites in vitro. Of importance, the iqg1-4A mutant rescued the inability of cdc14-1 cells to form actin rings. Our data support a model in which dephosphorylation of Cdk sites around the Iqg1 CHD by Cdc14 is both necessary and sufficient to promote actin ring formation. Temporal control of actin ring assembly by Cdk and Cdc14 may help to ensure that cytokinesis onset occurs after nuclear division is complete.
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Affiliation(s)
- Daniel P. Miller
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65401
| | - Hana Hall
- Department of Biochemistry, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Ryan Chaparian
- Department of Biochemistry, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Madison Mara
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65401
| | - Alison Mueller
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65401
| | - Mark C. Hall
- Department of Biochemistry, Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907
| | - Katie B. Shannon
- Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65401
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30
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Kaźmierczak-Barańska J, Pęczek Ł, Przygodzka P, Cieślak MJ. Downregulation of striatin leads to hyperphosphorylation of MAP2, induces depolymerization of microtubules and inhibits proliferation of HEK293T cells. FEBS Lett 2014; 589:222-30. [PMID: 25497017 DOI: 10.1016/j.febslet.2014.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 11/25/2014] [Accepted: 12/02/2014] [Indexed: 01/11/2023]
Abstract
Microtubules are tubular polymers of α/β-tubulin that are involved in the maintenance of cell shape, motility, and intracellular transport and in the segregation of chromosomes during cell division. Microtubules are dynamic structures, and their assembly is regulated by phosphoproteins called microtubule-associated proteins (MAPs). We propose that striatin, a protein belonging to the striatin family of proteins, is involved in regulation of microtubules. In HEK293T cells, striatin colocalizes with microtubules and stably associates with PP2Ac. Inhibition of striatin expression results in hyperphosphorylation of MAP2 and destabilizes microtubules. Striatin-induced destabilization of microtubules inhibited the proliferation of HEK293T cells and caused the accumulation of cells in the G0/G1 phase of the cell cycle. These results suggest that the PP2A/striatin complex modulates microtubule dynamics by regulating MAP2 phosphorylation.
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Affiliation(s)
- Julia Kaźmierczak-Barańska
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 112 Sienkiewicza St., 90-363 Lodz, Poland.
| | - Łukasz Pęczek
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 112 Sienkiewicza St., 90-363 Lodz, Poland
| | - Patrycja Przygodzka
- Institute for Medical Biology of the Polish Academy of Sciences, 106 Lodowa St., 93-232 Lodz, Poland.
| | - Marcin J Cieślak
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 112 Sienkiewicza St., 90-363 Lodz, Poland.
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31
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Abstract
The giant ciliated protozoan Stentor coeruleus is re-emerging as a model organism for morphogenesis and patterning in unicellular organisms. A new study provides evidence that cytokinesis and morphogenesis are mechanistically linked through the Mob1 protein.
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Affiliation(s)
- Douglas L Chalker
- Department of Biology, Washington University in St. Louis, 1 Brookings Drive, St. Louis, Missouri 63130, USA.
| | - Joseph Frankel
- Department of Biology, University of Iowa, 129 East Jefferson Street, Iowa City, Iowa 52242, USA
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32
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Tang F, Zhang L, Xue G, Hynx D, Wang Y, Cron PD, Hundsrucker C, Hergovich A, Frank S, Hemmings BA, Schmitz-Rohmer D. hMOB3 modulates MST1 apoptotic signaling and supports tumor growth in glioblastoma multiforme. Cancer Res 2014; 74:3779-89. [PMID: 24872389 PMCID: PMC4102567 DOI: 10.1158/0008-5472.can-13-3430] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
New therapeutic targets are needed that circumvent inherent therapeutic resistance of glioblastoma multiforme (GBM). Here, we report such a candidate target in the uncharacterized adaptor protein hMOB3, which we show is upregulated in GBM. In a search for its biochemical function, we found that hMOB3 specifically interacts with MST1 kinase in response to apoptotic stimuli and cell-cell contact. Moreover, hMOB3 negatively regulated apoptotic signaling by MST1 in GBM cells by inhibiting the MST1 cleavage-based activation process. Physical interaction between hMOB3 and MST1 was essential for this process. In vivo investigations established that hMOB3 sustains GBM cell growth at high cell density and promotes tumorigenesis. Our results suggest hMOB3 as a candidate therapeutic target for the treatment of malignant gliomas.
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Affiliation(s)
- Fengyuan Tang
- Authors' Affiliations: Friedrich Miescher Institute for Biomedical Research;
| | - Lei Zhang
- Authors' Affiliations: Friedrich Miescher Institute for Biomedical Research
| | - Gongda Xue
- Authors' Affiliations: Friedrich Miescher Institute for Biomedical Research
| | - Debby Hynx
- Authors' Affiliations: Friedrich Miescher Institute for Biomedical Research
| | - Yuhua Wang
- Authors' Affiliations: Friedrich Miescher Institute for Biomedical Research
| | - Peter D Cron
- Authors' Affiliations: Friedrich Miescher Institute for Biomedical Research
| | - Christian Hundsrucker
- Authors' Affiliations: Friedrich Miescher Institute for Biomedical Research; Swiss Institute of Bioinformatics, Basel, Switzerland; and
| | | | - Stephan Frank
- Division of Neuropathology, Institute of Pathology, University of Basel
| | - Brian A Hemmings
- Authors' Affiliations: Friedrich Miescher Institute for Biomedical Research
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Slabodnick MM, Ruby JG, Dunn JG, Feldman JL, DeRisi JL, Marshall WF. The kinase regulator mob1 acts as a patterning protein for stentor morphogenesis. PLoS Biol 2014; 12:e1001861. [PMID: 24823688 PMCID: PMC4019465 DOI: 10.1371/journal.pbio.1001861] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 04/07/2014] [Indexed: 01/11/2023] Open
Abstract
Here we demonstrate that RNAi can be used in molecular studies of the giant single-celled ciliate Stentor coeruleus, revealing morphogenetic functions of Mob1 and highlighting the potential of this classical model for studies of morphogenesis and regeneration. Morphogenesis and pattern formation are vital processes in any organism, whether unicellular or multicellular. But in contrast to the developmental biology of plants and animals, the principles of morphogenesis and pattern formation in single cells remain largely unknown. Although all cells develop patterns, they are most obvious in ciliates; hence, we have turned to a classical unicellular model system, the giant ciliate Stentor coeruleus. Here we show that the RNA interference (RNAi) machinery is conserved in Stentor. Using RNAi, we identify the kinase coactivator Mob1—with conserved functions in cell division and morphogenesis from plants to humans—as an asymmetrically localized patterning protein required for global patterning during development and regeneration in Stentor. Our studies reopen the door for Stentor as a model regeneration system. Cells have the ability to develop complex morphologies, but the mechanisms that determine these varied shapes are not well understood. Cell shape determination can be challenging to study in multicellular organisms because it can be difficult to know whether shape changes are determined internally within an individual cell or externally, driven by input from neighboring cells or by both. The giant unicellular ciliate, Stentor coeruleus, provides an ideal single-cell model in which to study morphogenesis due to its large size and reproducible, complex patterning. Although Stentor was a popular experimental organism around 100 years ago, molecular tools were not subsequently developed to sustain its use as a model system today. Here we demonstrate that RNA interference (RNAi) “by feeding” is effective in Stentor and demonstrate its utility for studying morphogenesis and cell polarity patterning in this organism. We show that the conserved Mob1 kinase regulator protein is asymmetrically localized to the posterior end of Stentor and is positioned at the newly forming posterior pole during cell division, suggesting that it may have a role in morphogenesis. Using RNAi, we show that depletion of Mob1 results in Stentor cells with marked defects in morphogenesis. Our findings suggest that Stentor coeruleus can be a powerful model system studying morphogenesis and regeneration at the single-cell level and that Mob1 is a patterning protein required for its normal development and regeneration.
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Affiliation(s)
- Mark M. Slabodnick
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
- * E-mail: (MMS); (WFM)
| | - J. Graham Ruby
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Joshua G. Dunn
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Jessica L. Feldman
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Joseph L. DeRisi
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Wallace F. Marshall
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
- * E-mail: (MMS); (WFM)
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Rizk RS, Discipio KA, Proudfoot KG, Gupta ML. The kinesin-8 Kip3 scales anaphase spindle length by suppression of midzone microtubule polymerization. ACTA ACUST UNITED AC 2014; 204:965-75. [PMID: 24616221 PMCID: PMC3998799 DOI: 10.1083/jcb.201312039] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mitotic spindle function is critical for cell division and genomic stability. During anaphase, the elongating spindle physically segregates the sister chromatids. However, the molecular mechanisms that determine the extent of anaphase spindle elongation remain largely unclear. In a screen of yeast mutants with altered spindle length, we identified the kinesin-8 Kip3 as essential to scale spindle length with cell size. Kip3 is a multifunctional motor protein with microtubule depolymerase, plus-end motility, and antiparallel sliding activities. Here we demonstrate that the depolymerase activity is indispensable to control spindle length, whereas the motility and sliding activities are not sufficient. Furthermore, the microtubule-destabilizing activity is required to counteract Stu2/XMAP215-mediated microtubule polymerization so that spindle elongation terminates once spindles reach the appropriate final length. Our data support a model where Kip3 directly suppresses spindle microtubule polymerization, limiting midzone length. As a result, sliding forces within the midzone cannot buckle spindle microtubules, which allows the cell boundary to define the extent of spindle elongation.
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Affiliation(s)
- Rania S Rizk
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL 60637
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Baro B, Rodriguez-Rodriguez JA, Calabria I, Hernáez ML, Gil C, Queralt E. Dual Regulation of the mitotic exit network (MEN) by PP2A-Cdc55 phosphatase. PLoS Genet 2013; 9:e1003966. [PMID: 24339788 PMCID: PMC3854864 DOI: 10.1371/journal.pgen.1003966] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 10/04/2013] [Indexed: 12/17/2022] Open
Abstract
Exit from mitosis in budding yeast is triggered by activation of the key mitotic phosphatase Cdc14. At anaphase onset, the protease separase and Zds1 promote the downregulation of PP2ACdc55 phosphatase, which facilitates Cdk1-dependent phosphorylation of Net1 and provides the first wave of Cdc14 activity. Once Cdk1 activity starts to decline, the mitotic exit network (MEN) is activated to achieve full Cdc14 activation. Here we describe how the PP2ACdc55 phosphatase could act as a functional link between FEAR and MEN due to its action on Bfa1 and Mob1. We demonstrate that PP2ACdc55 regulates MEN activation by facilitating Cdc5- and Cdk1-dependent phosphorylation of Bfa1 and Mob1, respectively. Downregulation of PP2ACdc55 initiates MEN activity up to Cdc15 by Bfa1 inactivation. Surprisingly, the premature Bfa1 inactivation observed does not entail premature MEN activation, since an additional Cdk1-Clb2 inhibitory signal acting towards Dbf2-Mob1 activity restrains MEN activity until anaphase. In conclusion, we propose a clear picture of how PP2ACdc55 functions affect the regulation of various MEN components, contributing to mitotic exit. Cell cycle studies over the years have tried to elucidate the molecular mechanisms behind cell division, one of the most highly regulated of all cell processes, which ensures life in all organisms. Protein phosphorylation emerged as a key regulatory mechanism in the cell cycle. The highly conserved family of cyclin-dependent kinases, the Cdks, are considered the main component of the cell cycle control system. However, it has become clear that opposing phosphatases also play a key role in determining the phosphorylation state of the proteins. Cells enter mitosis when mitotic Cdk activity increases, having its pick of activity during metaphase. To exit mitosis, cells must coordinate chromosome segregation with Cdk inactivation processes involving the activation of protein phosphatases. Here we show that the phosphatase PP2A regulates the mitotic exit network (MEN) by counteracting the phosphorylation of Bfa1 and Mob1. Our findings provide new insights into the mechanism by which PP2A-Cdc55 functions affect the regulation of various MEN components that contribute to mitotic exit. The core signalling elements of the MEN, SIN and Hippo pathways are highly conserved. Therefore, studies of MEN regulation will contribute to our understanding of MEN-related pathways in other organisms.
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Affiliation(s)
- Barbara Baro
- Cell Cycle Group, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Jose-Antonio Rodriguez-Rodriguez
- Cell Cycle Group, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Ines Calabria
- Cell Cycle Group, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - María Luisa Hernáez
- Unidad de Proteómica, Parque Científico de Madrid, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Concha Gil
- Unidad de Proteómica, Parque Científico de Madrid, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain
| | - Ethel Queralt
- Cell Cycle Group, Cancer Epigenetics and Biology Program (PEBC), Institut d'Investigacions Biomèdica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
- * E-mail:
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Pinosa F, Begheldo M, Pasternak T, Zermiani M, Paponov IA, Dovzhenko A, Barcaccia G, Ruperti B, Palme K. The Arabidopsis thaliana Mob1A gene is required for organ growth and correct tissue patterning of the root tip. ANNALS OF BOTANY 2013; 112:1803-14. [PMID: 24201137 PMCID: PMC3838559 DOI: 10.1093/aob/mct235] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 07/22/2013] [Accepted: 08/20/2013] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS The Mob1 family includes a group of kinase regulators conserved throughout eukaryotes. In multicellular organisms, Mob1 is involved in cell proliferation and apoptosis, thus controlling appropriate cell number and organ size. These functions are also of great importance for plants, which employ co-ordinated growth processes to explore the surrounding environment and respond to changing external conditions. Therefore, this study set out to investigate the role of two Arabidopsis thaliana Mob1-like genes, namely Mob1A and Mob1B, in plant development. METHODS A detailed spatio-temporal analysis of Mob1A and Mob1B gene expression was performed by means of bioinformatic tools, the generation of expression reporter lines and in situ hybridization of gene-specific probes. To explore the function of the two genes in plant development, knock-out and knock-down mutants were isolated and their phenotype quantitatively characterized. KEY RESULTS Transcripts of the two genes were detected in specific sets of cells in all plant organs. Mob1A was upregulated by several stress conditions as well as by abscisic acid and salicylic acid. A knock-out mutation in Mob1B did not cause any visible defect in plant development, whereas suppression of Mob1A expression affected organ growth and reproduction. In the primary root, reduced levels of Mob1A expression brought about severe defects in tissue patterning of the stem cell niche and columella and led to a decrease in meristem size. Moreover, loss of Mob1A function resulted in a higher sensitivity of root growth to abscisic acid. CONCLUSIONS Taken together, the results indicate that arabidopsis Mob1A is involved in the co-ordination of tissue patterning and organ growth, similarly to its orthologues in other multicellular eukaryotes. In addition, Mob1A serves a plant-specific function by contributing to growth adjustments in response to stress conditions.
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Affiliation(s)
- Francesco Pinosa
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Maura Begheldo
- Department of Agriculture, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Agripolis, viale dell'Università, 16, 35020 Legnaro (PD), Italy
| | - Taras Pasternak
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Monica Zermiani
- Department of Agriculture, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Agripolis, viale dell'Università, 16, 35020 Legnaro (PD), Italy
| | - Ivan A. Paponov
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Alexander Dovzhenko
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
| | - Gianni Barcaccia
- Department of Agriculture, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Agripolis, viale dell'Università, 16, 35020 Legnaro (PD), Italy
| | - Benedetto Ruperti
- Department of Agriculture, Food, Natural resources, Animals and Environment (DAFNAE), University of Padova, Agripolis, viale dell'Università, 16, 35020 Legnaro (PD), Italy
| | - Klaus Palme
- Institute of Biology II/Molecular Plant Physiology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
- Centre for Biological Systems Analysis, Albert-Ludwigs-University of Freiburg, Habsburgerstrasse 49, D-79104 Freiburg, Germany
- Freiburg Institute for Advanced Sciences (FRIAS), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany
- Centre for Biological Signalling Studies (bioss), Albert-Ludwigs-University of Freiburg, Albertstrasse 19, D-79104 Freiburg, Germany
- Freiburg Initiative for Systems Biology (FRISYS), Albert-Ludwigs-University of Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany
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Assessment of gene expression profiles in primary and secondary zoospores of Plasmodiophora brassicae by dot blot and real-time PCR. Microbiol Res 2013; 168:518-24. [DOI: 10.1016/j.micres.2013.02.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 02/23/2013] [Accepted: 02/23/2013] [Indexed: 01/11/2023]
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Identification of Mob2, a novel regulator of larval neuromuscular junction morphology, in natural populations of Drosophila melanogaster. Genetics 2013; 195:915-26. [PMID: 23979583 DOI: 10.1534/genetics.113.156562] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Although evolutionary changes must take place in neural connectivity and synaptic architecture as nervous systems become more complex, we lack understanding of the general principles and specific mechanisms by which these changes occur. Previously, we found that morphology of the larval neuromuscular junction (NMJ) varies extensively among different species of Drosophila but is relatively conserved within a species. To identify specific genes as candidates that might underlie phenotypic differences in NMJ morphology among Drosophila species, we performed a genetic analysis on one of two phenotypic variants we found among 20 natural isolates of Drosophila melanogaster. We discovered genetic polymorphisms for both positive and negative regulators of NMJ growth segregating within the variant line. Focusing on one subline, that displayed NMJ overgrowth, we mapped the phenotype to Mob2 [Monopolar spindle (Mps) one binding protein 2)], a gene encoding a Nuclear Dbf2 (Dumbbell formation 2)-Related (NDR) kinase activator. We confirmed this identification by transformation rescue experiments and showed that presynaptic expression of Mob2 is necessary and sufficient to regulate NMJ growth. Mob2 interacts in a dominant, dose-dependent manner with tricornered but not with warts, to cause NMJ overgrowth, suggesting that Mob2 specifically functions in combination with the former NDR kinase to regulate NMJ development. These results demonstrate the feasibility and utility of identifying genetic variants affecting NMJ morphology in natural populations of Drosophila. These variants can lead to discovery of new genes and molecular mechanisms that regulate NMJ development while also providing new information that can advance our understanding of mechanisms that underlie nervous system evolution.
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The RNA-binding protein Whi3 is a key regulator of developmental signaling and ploidy in Saccharomyces cerevisiae. Genetics 2013; 195:73-86. [PMID: 23770701 DOI: 10.1534/genetics.113.153775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In Saccharomyces cerevisiae, the RNA-binding protein Whi3 controls cell cycle progression, biofilm formation, and stress response by post-transcriptional regulation of the Cdc28-Cln3 cyclin-dependent protein kinase and the dual-specificity protein kinase Yak1. Previous work has indicated that Whi3 might govern these processes by additional, yet unknown mechanisms. In this study, we have identified additional effectors of Whi3 that include the G1 cyclins Cln1/Cln2 and two known regulators of biofilm formation, the catalytic PKA subunit Tpk1 and the transcriptional activator Tec1. We also provide evidence that Whi3 regulates production of these factors by post-transcriptional control and might exert this function by affecting translational elongation. Unexpectedly, we also discovered that Whi3 is a key regulator of cellular ploidy, because haploid whi3Δ mutant strains exhibit a significant increase-in-ploidy phenotype that depends on environmental conditions. Our data further suggest that Whi3 might control stability of ploidy by affecting the expression of many key genes involved in sister chromatid cohesion and of NIP100 that encodes a component of the yeast dynactin complex for chromosome distribution. Finally, we show that absence of Whi3 induces a transcriptional stress response in haploid cells that is relieved by whole-genome duplication. In summary, our study suggests that the RNA-binding protein Whi3 acts as a central regulator of cell division and development by post-transcriptional control of key genes involved in chromosome distribution and cell signaling.
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Abstract
Productive cell proliferation involves efficient and accurate splitting of the dividing cell into two separate entities. This orderly process reflects coordination of diverse cytological events by regulatory systems that drive the cell from mitosis into G1. In the budding yeast Saccharomyces cerevisiae, separation of mother and daughter cells involves coordinated actomyosin ring contraction and septum synthesis, followed by septum destruction. These events occur in precise and rapid sequence once chromosomes are segregated and are linked with spindle organization and mitotic progress by intricate cell cycle control machinery. Additionally, critical paarts of the mother/daughter separation process are asymmetric, reflecting a form of fate specification that occurs in every cell division. This chapter describes central events of budding yeast cell separation, as well as the control pathways that integrate them and link them with the cell cycle.
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Leng JJ, Tan HM, Chen K, Shen WG, Tan JW. Growth-inhibitory effects of MOB2 on human hepatic carcinoma cell line SMMC-7721. World J Gastroenterol 2012; 18:7285-9. [PMID: 23326134 PMCID: PMC3544031 DOI: 10.3748/wjg.v18.i48.7285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 08/08/2011] [Accepted: 08/15/2011] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the growth-inhibiting and apoptosis-inducing effects of the gene MOB2 on human hepatic carcinoma cell line SMMC-7721.
METHODS: The full-length cDNA of the MOB2 gene was amplified from human umbilical vein endothelial cells. The correct full-length MOB2 cDNA was subcloned into the eukaryotic expression vector pEGFP-C1. After lipofection of the MOB2 gene into cancer cells, the levels of MOB2 protein in the cancer cells were detected by immunoblotting. To transfect the recombined plasmid vector pEGFP-CI-MOB2 into SMMC-7721 cells, the cells were cultured in Dulbecco’s Modified Eagle’s Medium with 10% fetal calf serum and glutamine, and then mixed with liposomes, Lipofectamine 2000 and the plasmid vector pEGFP-CI-MOB2.
RESULTS: We observed the growth and proliferation of SMMC-7721 cells containing pEGFP-CI-MOB2 and analyzed their apoptosis and growth cycle phases by flow cytometry. We successfully transfected the recombined plasmid vector pEGFP-CI-MOB2 into SMMC-7721 cells and screened for a single clone cell containing MOB2. After transfection, MOB2 enhanced growth suppression, induced apoptosis, increased the ratio of G0/G1, significantly inhibited the advance of cell cycle phase, and arrested cells in G0/G1 phase.
CONCLUSION: MOB2 overexpression induces apoptosis and inhibits the growth of human hepatic cancer cells, which may be useful in gene therapy for hepatic carcinoma.
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Nishio M, Hamada K, Kawahara K, Sasaki M, Noguchi F, Chiba S, Mizuno K, Suzuki SO, Dong Y, Tokuda M, Morikawa T, Hikasa H, Eggenschwiler J, Yabuta N, Nojima H, Nakagawa K, Hata Y, Nishina H, Mimori K, Mori M, Sasaki T, Mak TW, Nakano T, Itami S, Suzuki A. Cancer susceptibility and embryonic lethality in Mob1a/1b double-mutant mice. J Clin Invest 2012; 122:4505-18. [PMID: 23143302 DOI: 10.1172/jci63735] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 09/13/2012] [Indexed: 12/31/2022] Open
Abstract
Mps one binder 1a (MOB1A) and MOB1B are key components of the Hippo signaling pathway and are mutated or inactivated in many human cancers. Here we show that intact Mob1a or Mob1b is essential for murine embryogenesis and that loss of the remaining WT Mob1 allele in Mob1a(Δ/Δ)1b(tr/+) or Mob1a(Δ/+)1b(tr/tr) mice results in tumor development. Because most of these cancers resembled trichilemmal carcinomas, we generated double-mutant mice bearing tamoxifen-inducible, keratinocyte-specific homozygous-null mutations of Mob1a and Mob1b (kDKO mice). kDKO mice showed hyperplastic keratinocyte progenitors and defective keratinocyte terminal differentiation and soon died of malnutrition. kDKO keratinocytes exhibited hyperproliferation, apoptotic resistance, impaired contact inhibition, enhanced progenitor self renewal, and increased centrosomes. Examination of Hippo pathway signaling in kDKO keratinocytes revealed that loss of Mob1a/b altered the activities of the downstream Hippo mediators LATS and YAP1. Similarly, YAP1 was activated in some human trichilemmal carcinomas, and some of these also exhibited MOB1A/1B inactivation. Our results clearly demonstrate that MOB1A and MOB1B have overlapping functions in skin homeostasis, and exert their roles as tumor suppressors by regulating downstream elements of the Hippo pathway.
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Affiliation(s)
- Miki Nishio
- Division of Cancer Genetics, Medical Institute of Bioregulation, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Abstract
The mitotic exit network (MEN), a pathway essential for vegetative growth, is largely dispensable for the specialized meiotic divisions, contributing only to timely exit from meiosis II. MEN activity is restricted to meiosis II by multiple regulatory mechanisms distinct from those operative in mitosis. The mitotic exit network (MEN) is an essential GTPase signaling pathway that triggers exit from mitosis in budding yeast. We show here that during meiosis, the MEN is dispensable for exit from meiosis I but contributes to the timely exit from meiosis II. Consistent with a role for the MEN during meiosis II, we find that the signaling pathway is active only during meiosis II. Our analysis further shows that MEN signaling is modulated during meiosis in several key ways. Whereas binding of MEN components to spindle pole bodies (SPBs) is necessary for MEN signaling during mitosis, during meiosis MEN signaling occurs off SPBs and does not require the SPB recruitment factor Nud1. Furthermore, unlike during mitosis, MEN signaling is controlled through the regulated interaction between the MEN kinase Dbf20 and its activating subunit Mob1. Our data lead to the conclusion that a pathway essential for vegetative growth is largely dispensable for the specialized meiotic divisions and provide insights into how cell cycle regulatory pathways are modulated to accommodate different modes of cell division.
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Affiliation(s)
- Michelle A Attner
- David H. Koch Institute for Integrative Cancer Research and Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Hergovich A, Hemmings BA. Hippo signalling in the G2/M cell cycle phase: lessons learned from the yeast MEN and SIN pathways. Semin Cell Dev Biol 2012; 23:794-802. [PMID: 22525225 DOI: 10.1016/j.semcdb.2012.04.001] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 04/03/2012] [Accepted: 04/04/2012] [Indexed: 01/11/2023]
Abstract
Over the past decade Hippo kinase signalling has been established as an essential tumour suppressor pathway controlling tissue growth in flies and mammals. All members of the Hippo core signalling cassette are conserved from yeast to humans, whereby the yeast analogues of Hippo, Mats and Lats are central components of the mitotic exit network and septation initiation network in budding and fission yeast, respectively. Here, we discuss how far core Hippo signalling components in Drosophila melanogaster and mammals have reported similar mitotic functions as already established for their highly conserved yeast counterparts.
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Hippo pathway in intestinal homeostasis and tumorigenesis. Protein Cell 2012; 3:305-10. [PMID: 22492181 DOI: 10.1007/s13238-012-2913-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 03/06/2012] [Indexed: 12/11/2022] Open
Abstract
The Hippo pathway plays a crucial role in controlling organ size by inhibiting cell proliferation and promoting cell death. Recent findings implicate that this pathway is involved in the process of intestinal regeneration and tumorigenesis. Here we summarize current studies for the function of the Hippo signaling pathway in intestinal homeostasis, regeneration and tumorigenesis, and the crosstalk between the Hippo signaling pathway and other major signaling pathways, i.e. Wnt, Notch and Jak/Stat signaling pathways in intestinal compartment.
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Abstract
MPS1 protein kinases are found widely, but not ubiquitously, in eukaryotes. This family of potentially dual-specific protein kinases is among several that regulate a number of steps of mitosis. The most widely conserved MPS1 kinase functions involve activities at the kinetochore in both the chromosome attachment and the spindle checkpoint. MPS1 kinases also function at centrosomes. Beyond mitosis, MPS1 kinases have been implicated in development, cytokinesis, and several different signaling pathways. Family members are identified by virtue of a conserved C-terminal kinase domain, though the N-terminal domain is quite divergent. The kinase domain of the human enzyme has been crystallized, revealing an unusual ATP-binding pocket. The activity, level, and subcellular localization of Mps1 family members are tightly regulated during cell-cycle progression. The mitotic functions of Mps1 kinases and their overexpression in some tumors have prompted the identification of Mps1 inhibitors and their active development as anticancer drugs.
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Affiliation(s)
- Xuedong Liu
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA.
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Tzeng YW, Huang JN, Schuyler SC, Wu CH, Juang YL. Functions of the mitotic B-type cyclins CLB1, CLB2, and CLB3 at mitotic exit antagonized by the CDC14 phosphatase. Fungal Genet Biol 2011; 48:966-78. [DOI: 10.1016/j.fgb.2011.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 07/05/2011] [Accepted: 07/06/2011] [Indexed: 01/11/2023]
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Hergovich A. MOB control: reviewing a conserved family of kinase regulators. Cell Signal 2011; 23:1433-40. [PMID: 21539912 PMCID: PMC3398134 DOI: 10.1016/j.cellsig.2011.04.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 04/13/2011] [Indexed: 01/01/2023]
Abstract
The family of Mps One binder (MOB) co-activator proteins is highly conserved from yeast to man. At least two different MOB proteins have been identified in every eukaryote analysed to date. Initially, yeast genetics revealed essential roles for Mob1p and Mob2p in the regulation of mitotic exit and cell morphogenesis. Studies in flies then showed that dMOB1/MATS is a core component of Hippo signalling. Loss of dMOB1 resulted in increased cell proliferation and decreased cell death, suggesting that MOB1 acts as tumour suppressor protein. Recent work focused primarily on mammalian cells has shown how hMOB1 can regulate NDR/LATS kinases, a function that can to be counteracted by hMOB2. Here we summarise and discuss our current knowledge of this emerging protein family, with emphasis on subcellular localisation, protein-protein interactions and biological functions in apoptosis, mitosis, morphogenesis, cell proliferation and centrosome duplication.
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Affiliation(s)
- Alexander Hergovich
- Tumour Suppressor Signalling Networks laboratory, UCL Cancer Institute, University College London, WC1E 6BT, London, United Kingdom.
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Bao Y, Hata Y, Ikeda M, Withanage K. Mammalian Hippo pathway: from development to cancer and beyond. J Biochem 2011; 149:361-79. [PMID: 21324984 DOI: 10.1093/jb/mvr021] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Hippo pathway was discovered as a signal transduction pathway that regulates organ size in Drosophila melanogaster. It is composed of three components: cell surface upstream regulators including cell adhesion molecules and cell polarity complexes; a kinase cascade comprising two serine-threonine kinases with regulators and adaptors; and a downstream target, a transcription coactivator. The coactivator mediates the transcription of cell proliferation-promoting and anti-apoptotic genes. The pathway negatively regulates the coactivator to restrict cell proliferation and to promote cell death. Thus, the pathway prevents tissue overgrowth and tumourigenesis. The framework of the pathway is conserved in mammals. A dysfunction of the pathway is frequently detected in human cancers and correlates with a poor prognosis. Recent works indicated that the Hippo pathway plays an important role in tissue homoeostasis through the regulation of stem cells, cell differentiation and tissue regeneration.
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Affiliation(s)
- Yijun Bao
- Department of Medical Biochemistry, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
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Lin CH, Hsieh M, Fan SS. The promotion of neurite formation in Neuro2A cells by mouse Mob2 protein. FEBS Lett 2011; 585:523-30. [PMID: 21237165 DOI: 10.1016/j.febslet.2011.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 12/22/2010] [Accepted: 01/03/2011] [Indexed: 01/11/2023]
Abstract
The molecular mechanism of neuritogenesis has been extensively studied but remains unclear. In this study, we identified Mob2 protein which plays a significant role in promoting neurite formation in Neuro2A (N2A) cells. Our results showed that Mob2 was expressed in developing N2A cells. To study whether Mob2 was involved in neurite formation, we downregulated Mob2 expression using RNA interference and found that neurite formation decreased in low serum induced N2A cells. In addition, we found that overexpression of Mob2 promoted neurite formation in N2A cells. Furthermore, downregulation of Mob2 expression altered the rearrangement of the actin cytoskeleton and decreased the expression of phosphorylated Moesin. Together, these results provide information on the role of Mob2 in mediating neurite formation.
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Affiliation(s)
- Cheng-Han Lin
- Department of Life Science, Tunghai University, Taichung, Taiwan, Republic of China
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