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Ratanayotha A, Iida A, Nomura J, Hondo E, Okamura Y, Kawai T. Insight into the function of voltage-sensing phosphatase in hindgut-derived pseudoplacenta of a viviparous teleost Xenotoca eiseni. Am J Physiol Regul Integr Comp Physiol 2024; 326:R461-R471. [PMID: 38557151 DOI: 10.1152/ajpregu.00038.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/13/2024] [Accepted: 03/22/2024] [Indexed: 04/04/2024]
Abstract
Nutrient absorption is essential for animal survival and development. Our previous study on zebrafish reported that nutrient absorption in lysosome-rich enterocytes (LREs) is promoted by the voltage-sensing phosphatase (VSP), which regulates phosphoinositide (PIP) homeostasis via electrical signaling in biological membranes. However, it remains unknown whether this VSP function is shared by different absorptive tissues in other species. Here, we focused on the function of VSP in a viviparous teleost Xenotoca eiseni, whose intraovarian embryos absorb nutrients from the maternal ovarian fluid through a specialized hindgut-derived pseudoplacental structure called trophotaenia. Xenotoca eiseni VSP (Xe-VSP) is expressed in trophotaenia epithelium, an absorptive tissue functionally similar to zebrafish LREs. Notably, the apical distribution of Xe-VSP in trophotaenia epithelial cells closely resembles zebrafish VSP (Dr-VSP) distribution in zebrafish LREs, suggesting a shared role for VSP in absorptive tissues between the two species. Electrophysiological analysis using a heterologous expression system revealed that Xe-VSP preserves functional voltage sensors and phosphatase activity with the leftward shifted voltage sensitivity compared with zebrafish VSP (Dr-VSP). We also identified a single amino acid variation in the S4 helix of Xe-VSP as one of the factors contributing to the leftward shifted voltage sensitivity. This study highlights the biological variation and significance of VSP in various animal species, as well as hinting at the potential role of VSP in nutrient absorption in X. eiseni trophotaenia.NEW & NOTEWORTHY We investigate the voltage-sensing phosphatase (VSP) in Xenotoca eiseni, a viviparous fish whose intraovarian embryos utilize trophotaenia for nutrient absorption. Although X. eiseni VSP (Xe-VSP) shares key features with known VSPs, its distinct voltage sensitivity arises from species-specific amino acid variation. Xe-VSP in trophotaenia epithelium suggests its involvement in nutrient absorption, similar to VSP in zebrafish enterocytes and potentially in species with similar absorptive cells. Our findings highlight the potential role of VSP across species.
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Affiliation(s)
- Adisorn Ratanayotha
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan
- Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Atsuo Iida
- Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Jumpei Nomura
- Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Eiichi Hondo
- Department of Animal Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
| | - Yasushi Okamura
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Takafumi Kawai
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Osaka, Japan
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2
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Nin DS, Deng LW. Biology of Cancer-Testis Antigens and Their Therapeutic Implications in Cancer. Cells 2023; 12:cells12060926. [PMID: 36980267 PMCID: PMC10047177 DOI: 10.3390/cells12060926] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/30/2023] Open
Abstract
Tumour-specific antigens have been an area of interest in cancer therapy since their discovery in the middle of the 20th century. In the era of immune-based cancer therapeutics, redirecting our immune cells to target these tumour-specific antigens has become even more relevant. Cancer-testis antigens (CTAs) are a class of antigens with an expression specific to the testis and cancer cells. CTAs have also been demonstrated to be expressed in a wide variety of cancers. Due to their frequency and specificity of expression in a multitude of cancers, CTAs have been particularly attractive as cancer-specific therapeutic targets. There is now a rapid expansion of CTAs being identified and many studies have been conducted to correlate CTA expression with cancer and therapy-resistant phenotypes. Furthermore, there is an increasing number of clinical trials involving using some of these CTAs as molecular targets in pharmacological and immune-targeted therapeutics for various cancers. This review will summarise the current knowledge of the biology of known CTAs in tumorigenesis and the regulation of CTA genes. CTAs as molecular targets and the therapeutic implications of these CTA-targeted anticancer strategies will also be discussed.
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Affiliation(s)
- Dawn Sijin Nin
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD 7, 8 Medical Drive, Singapore 117596, Singapore
- NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599, Singapore
| | - Lih-Wen Deng
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD 7, 8 Medical Drive, Singapore 117596, Singapore
- NUS Center for Cancer Research, Yong Loo Lin School of Medicine, National University of Singapore, 14 Medical Drive, Singapore 117599, Singapore
- National University Cancer Institute, National University Health System, 5 Lower Kent Ridge Road, Singapore 119074, Singapore
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3
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Voltage-sensing phosphatase (Vsp) regulates endocytosis-dependent nutrient absorption in chordate enterocytes. Commun Biol 2022; 5:948. [PMID: 36088390 PMCID: PMC9464190 DOI: 10.1038/s42003-022-03916-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 08/30/2022] [Indexed: 11/11/2022] Open
Abstract
Voltage-sensing phosphatase (Vsp) is a unique membrane protein that translates membrane electrical activities into the changes of phosphoinositide profiles. Vsp orthologs from various species have been intensively investigated toward their biophysical properties, primarily using a heterologous expression system. In contrast, the physiological role of Vsp in native tissues remains largely unknown. Here we report that zebrafish Vsp (Dr-Vsp), encoded by tpte gene, is functionally expressed on the endomembranes of lysosome-rich enterocytes (LREs) that mediate dietary protein absorption via endocytosis in the zebrafish mid-intestine. Dr-Vsp-deficient LREs were remarkably defective in forming endosomal vacuoles after initial uptake of dextran and mCherry. Dr-Vsp-deficient zebrafish exhibited growth restriction and higher mortality during the critical period when zebrafish larvae rely primarily on exogenous feeding via intestinal absorption. Furthermore, our comparative study on marine invertebrate Ciona intestinalis Vsp (Ci-Vsp) revealed co-expression with endocytosis-associated genes in absorptive epithelial cells of the Ciona digestive tract, corresponding to zebrafish LREs. These findings signify a crucial role of Vsp in regulating endocytosis-dependent nutrient absorption in specialized enterocytes across animal species. The physiological role of Vsp in zebrafish is assessed, revealing Vsp expression in the mid-intestine for dietary protein absorption. A comparative study on marine invertebrate Ciona intestinalis suggests conservation of Vsp function in the GI tract.
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4
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Ceyhan Y, Zhang M, Sandoval CG, Agoulnik AI, Agoulnik IU. Expression pattern and the roles of phosphatidylinositol phosphatases in testis. Biol Reprod 2022; 107:902-915. [PMID: 35766372 DOI: 10.1093/biolre/ioac132] [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: 03/23/2022] [Revised: 06/02/2022] [Accepted: 06/20/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphoinositides (PIs) are relatively rare lipid components of the cellular membranes. Their homeostasis is tightly controlled by specific PI kinases and phosphatases. PIs play essential roles in cellular signaling, cytoskeletal organization, and secretory processes in various diseases and normal physiology. Gene targeting experiments strongly suggest that in mice with deficiency of several PI phosphatases such as Pten, Mtmrs, Inpp4b, and Inpp5b, spermatogenesis is affected, resulting in partial or complete infertility. Similarly, in men, loss of several of the PIP phosphatases is observed in infertility characterized by the lack of mature sperm. Using available gene expression databases, we compare expression of known PI phosphatases in various testicular cell types, infertility patients, and mouse age-dependent testicular gene expression, and discuss their potential roles in testis physiology and spermatogenesis.
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Affiliation(s)
- Yasemin Ceyhan
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Manqi Zhang
- Department of Medicine, Duke University, Durham, NC, USA
| | - Carlos G Sandoval
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,New York University Grossman School of Medicine, New York, NY, USA
| | - Alexander I Agoulnik
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Irina U Agoulnik
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA.,Biomolecular Sciences Institute, Florida International University, Miami, FL, USA.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
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5
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Abstract
The complete, ungapped sequence of the short arms of human acrocentric chromosomes (SAACs) is still unknown almost 20 years after the near completion of the Human Genome Project. Yet these short arms of Chromosomes 13, 14, 15, 21, and 22 contain the ribosomal DNA (rDNA) genes, which are of paramount importance for human biology. The sequences of SAACs show an extensive variation in the copy number of the various repetitive elements, the full extent of which is currently unknown. In addition, the full spectrum of repeated sequences, their organization, and the low copy number functional elements are also unknown. The Telomere-to-Telomere (T2T) Project using mainly long-read sequence technology has recently completed the assembly of the genome from a hydatidiform mole, CHM13, and has thus established a baseline reference for further studies on the organization, variation, functional annotation, and impact in human disorders of all the previously unknown genomic segments, including the SAACs. The publication of the initial results of the T2T Project will update and improve the reference genome for a better understanding of the evolution and function of the human genome.
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Affiliation(s)
- Stylianos E Antonarakis
- Department of Genetic Medicine and Development, University of Geneva Medical Faculty, 1211 Geneva, Switzerland
- Foundation Campus Biotech, 1202 Geneva, Switzerland
- Medigenome, Swiss Institute of Genomic Medicine, 1207 Geneva, Switzerland
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6
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Tarabichi M, Demeulemeester J, Verfaillie A, Flanagan AM, Van Loo P, Konopka T. A pan-cancer landscape of somatic mutations in non-unique regions of the human genome. Nat Biotechnol 2021; 39:1589-1596. [PMID: 34282324 PMCID: PMC7612106 DOI: 10.1038/s41587-021-00971-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 06/02/2021] [Indexed: 12/27/2022]
Abstract
A substantial fraction of the human genome displays high sequence similarity with at least one other genomic sequence, posing a challenge for the identification of somatic mutations from short-read sequencing data. Here we annotate genomic variants in 2,658 cancers from the Pan-Cancer Analysis of Whole Genomes (PCAWG) cohort with links to similar sites across the human genome. We train a machine learning model to use signals distributed over multiple genomic sites to call somatic events in non-unique regions and validate the data against linked-read sequencing in an independent dataset. Using this approach, we uncover previously hidden mutations in ~1,700 coding sequences and in thousands of regulatory elements, including in known cancer genes, immunoglobulins and highly mutated gene families. Mutations in non-unique regions are consistent with mutations in unique regions in terms of mutation burden and substitution profiles. The analysis provides a systematic summary of the mutation events in non-unique regions at a genome-wide scale across multiple human cancers.
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Affiliation(s)
- Maxime Tarabichi
- The Francis Crick Institute, London, UK.
- Institute for Interdisciplinary Research, Université Libre de Bruxelles, Brussels, Belgium.
| | - Jonas Demeulemeester
- The Francis Crick Institute, London, UK
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | | | - Adrienne M Flanagan
- Research Department of Pathology, Cancer Institute, University College London, London, UK
- Department of Cellular and Molecular Pathology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, UK
| | | | - Tomasz Konopka
- The Francis Crick Institute, London, UK.
- William Harvey Research Institute, Queen Mary University of London, London, UK.
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7
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Pulido R, Mingo J, Gaafar A, Nunes-Xavier CE, Luna S, Torices L, Angulo JC, López JI. Precise Immunodetection of PTEN Protein in Human Neoplasia. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a036293. [PMID: 31501265 DOI: 10.1101/cshperspect.a036293] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PTEN is a major tumor-suppressor protein whose expression and biological activity are frequently diminished in sporadic or inherited cancers. PTEN gene deletion or loss-of-function mutations favor tumor cell growth and are commonly found in clinical practice. In addition, diminished PTEN protein expression is also frequently observed in tumor samples from cancer patients in the absence of PTEN gene alterations. This makes PTEN protein levels a potential biomarker parameter in clinical oncology, which can guide therapeutic decisions. The specific detection of PTEN protein can be achieved by using highly defined anti-PTEN monoclonal antibodies (mAbs), characterized with precision in terms of sensitivity for the detection technique, specificity for PTEN binding, and constraints of epitope recognition. This is especially relevant taking into consideration that PTEN is highly targeted by mutations and posttranslational modifications, and different PTEN protein isoforms exist. The precise characterization of anti-PTEN mAb reactivity is an important step in the validation of these reagents as diagnostic and prognostic tools in clinical oncology, including their routine use in analytical immunohistochemistry (IHC). Here, we review the current status on the use of well-defined anti-PTEN mAbs for PTEN immunodetection in the clinical context and discuss their potential usefulness and limitations for a more precise cancer diagnosis and patient benefit.
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Affiliation(s)
- Rafael Pulido
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao 48011, Spain
| | - Janire Mingo
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain
| | - Ayman Gaafar
- Department of Pathology, Cruces University Hospital, Barakaldo 48903, Spain
| | - Caroline E Nunes-Xavier
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain.,Department of Tumor Biology, Institute for Cancer Research, Oslo University Hospital Radiumhospitalet, Oslo N-0310, Norway
| | - Sandra Luna
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain
| | - Leire Torices
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain
| | - Javier C Angulo
- Department of Urology, University Hospital of Getafe, Getafe, Madrid 28904, Spain.,Clinical Department, European University of Madrid, Laureate Universities, Madrid 28904, Spain
| | - José I López
- Biocruces Bizkaia Health Research Institute, Barakaldo 48903, Spain.,Department of Pathology, Cruces University Hospital, Barakaldo 48903, Spain.,University of the Basque Country, Leioa 48940, Spain
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8
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Nakada-Tsukui K, Watanabe N, Maehama T, Nozaki T. Phosphatidylinositol Kinases and Phosphatases in Entamoeba histolytica. Front Cell Infect Microbiol 2019; 9:150. [PMID: 31245297 PMCID: PMC6563779 DOI: 10.3389/fcimb.2019.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/23/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphatidylinositol (PtdIns) metabolism is indispensable in eukaryotes. Phosphoinositides (PIs) are phosphorylated derivatives of PtdIns and consist of seven species generated by reversible phosphorylation of the inositol moieties at the positions 3, 4, and 5. Each of the seven PIs has a unique subcellular and membrane domain distribution. In the enteric protozoan parasite Entamoeba histolytica, it has been previously shown that the PIs phosphatidylinositol 3-phosphate (PtdIns3P), PtdIns(4,5)P2, and PtdIns(3,4,5)P3 are localized to phagosomes/phagocytic cups, plasma membrane, and phagocytic cups, respectively. The localization of these PIs in E. histolytica is similar to that in mammalian cells, suggesting that PIs have orthologous functions in E. histolytica. In contrast, the conservation of the enzymes that metabolize PIs in this organism has not been well-documented. In this review, we summarized the full repertoire of the PI kinases and PI phosphatases found in E. histolytica via a genome-wide survey of the current genomic information. E. histolytica appears to have 10 PI kinases and 23 PI phosphatases. It has a panel of evolutionarily conserved enzymes that generate all the seven PI species. However, class II PI 3-kinases, type II PI 4-kinases, type III PI 5-phosphatases, and PI 4P-specific phosphatases are not present. Additionally, regulatory subunits of class I PI 3-kinases and type III PI 4-kinases have not been identified. Instead, homologs of class I PI 3-kinases and PTEN, a PI 3-phosphatase, exist as multiple isoforms, which likely reflects that elaborate signaling cascades mediated by PtdIns(3,4,5)P3 are present in this organism. There are several enzymes that have the nuclear localization signal: one phosphatidylinositol phosphate (PIP) kinase, two PI 3-phosphatases, and one PI 5-phosphatase; this suggests that PI metabolism also has conserved roles related to nuclear functions in E. histolytica, as it does in model organisms.
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Affiliation(s)
- Kumiko Nakada-Tsukui
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Natsuki Watanabe
- Department of Parasitology, National Institute of Infectious Diseases, Tokyo, Japan.,Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tomohiko Maehama
- Division of Molecular and Cellular Biology, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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9
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Bhattacharyya T, Sowdhamini R. Genome-Wide Search for Tyrosine Phosphatases in the Human Genome Through Computational Approaches Leads to the Discovery of Few New Domain Architectures. Evol Bioinform Online 2019; 15:1176934319840289. [PMID: 31007525 PMCID: PMC6457024 DOI: 10.1177/1176934319840289] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 03/04/2019] [Indexed: 11/24/2022] Open
Abstract
Reversible phosphorylation maintained by protein kinases and phosphatases is an integral part of intracellular signalling, and phosphorylation on tyrosine is extensively utilised in higher eukaryotes. Tyrosine phosphatases are enzymes that not only scavenge phosphotyrosine but are also involved in wide range of signalling pathways. As a result, mutations in these enzymes have been implicated in the pathogenesis of several diseases like cancer, autoimmune disorders, and muscle-related diseases. The genes that harbour phosphatase domain also display diversity in co-existing domains suggesting the recruitment of the catalytic machinery in diverse pathways. We have examined the current draft of the human genome, using a combination of 3 sequence search methods and validations, and identified 101 genes encoding tyrosine phosphatase-containing gene products, agreeing with previous reports. Such gene products adopt 37 unique domain architectures (DAs), including few new ones and harbouring few co-existing domains that have not been reported before. This semi-automated computational approach for detection of gene products belonging to a particular superfamily can now be easily applied at whole genome level on other mammalian genomes and for other protein domains as well.
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Affiliation(s)
- Teerna Bhattacharyya
- National Centre for Biological Sciences, Tata
Institute of Fundamental Research, Bangalore, India
| | - Ramanathan Sowdhamini
- National Centre for Biological Sciences, Tata
Institute of Fundamental Research, Bangalore, India
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10
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Okamura Y, Kawanabe A, Kawai T. Voltage-Sensing Phosphatases: Biophysics, Physiology, and Molecular Engineering. Physiol Rev 2019; 98:2097-2131. [PMID: 30067160 DOI: 10.1152/physrev.00056.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-sensing phosphatase (VSP) contains a voltage sensor domain (VSD) similar to that in voltage-gated ion channels, and a phosphoinositide phosphatase region similar to phosphatase and tensin homolog deleted on chromosome 10 (PTEN). The VSP gene is conserved from unicellular organisms to higher vertebrates. Membrane depolarization induces electrical driven conformational rearrangement in the VSD, which is translated into catalytic enzyme activity. Biophysical and structural characterization has revealed details of the mechanisms underlying the molecular functions of VSP. Coupling between the VSD and the enzyme is tight, such that enzyme activity is tuned in a graded fashion to the membrane voltage. Upon VSP activation, multiple species of phosphoinositides are simultaneously altered, and the profile of enzyme activity depends on the history of the membrane potential. VSPs have been the obvious candidate link between membrane potential and phosphoinositide regulation. However, patterns of voltage change regulating VSP in native cells remain largely unknown. This review addresses the current understanding of the biophysical biochemical properties of VSP and provides new insight into the proposed functions of VSP.
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Affiliation(s)
- Yasushi Okamura
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
| | - Akira Kawanabe
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
| | - Takafumi Kawai
- Department of Physiology, Laboratory of Integrative Physiology, Graduate School of Medicine, Osaka University , Osaka , Japan ; and Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
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11
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Leitner MG, Hobiger K, Mavrantoni A, Feuer A, Oberwinkler J, Oliver D, Halaszovich CR. A126 in the active site and TI167/168 in the TI loop are essential determinants of the substrate specificity of PTEN. Cell Mol Life Sci 2018; 75:4235-4250. [PMID: 29987362 PMCID: PMC6182344 DOI: 10.1007/s00018-018-2867-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 06/19/2018] [Accepted: 07/03/2018] [Indexed: 01/16/2023]
Abstract
PTEN prevents tumor genesis by antagonizing the PI3 kinase/Akt pathway through D3 site phosphatase activity toward PI(3,4)P2 and PI(3,4,5)P3. The structural determinants of this important specificity remain unknown. Interestingly, PTEN shares remarkable homology to voltage-sensitive phosphatases (VSPs) that dephosphorylate D5 and D3 sites of PI(4,5)P2, PI(3,4)P2, and PI(3,4,5)P3. Since the catalytic center of PTEN and VSPs differ markedly only in TI/gating loop and active site motif, we wondered whether these differences explained the variation of their substrate specificity. Therefore, we introduced mutations into PTEN to mimic corresponding sequences of VSPs and studied phosphatase activity in living cells utilizing engineered, voltage switchable PTENCiV, a Ci-VSP/PTEN chimera that retains D3 site activity of the native enzyme. Substrate specificity of this enzyme was analyzed with whole-cell patch clamp in combination with total internal reflection fluorescence microscopy and genetically encoded phosphoinositide sensors. In PTENCiV, mutating TI167/168 in the TI loop into the corresponding ET pair of VSPs induced VSP-like D5 phosphatase activity toward PI(3,4,5)P3, but not toward PI(4,5)P2. Combining TI/ET mutations with an A126G exchange in the active site removed major sequence variations between PTEN and VSPs and resulted in D5 activity toward PI(4,5)P2 and PI(3,4,5)P3 of PTENCiV. This PTEN mutant thus fully reproduced the substrate specificity of native VSPs. Importantly, the same combination of mutations also induced D5 activity toward PI(3,4,5)P3 in native PTEN demonstrating that the same residues determine the substrate specificity of the tumor suppressor in living cells. Reciprocal mutations in VSPs did not alter their substrate specificity, but reduced phosphatase activity. In summary, A126 in the active site and TI167/168 in the TI loop are essential determinants of PTEN's substrate specificity, whereas additional features might contribute to the enzymatic activity of VSPs.
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Affiliation(s)
- Michael G Leitner
- Institute of Physiology and Pathophysiology, Philipps-University Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
- Division of Physiology, Department of Physiology and Medical Physics, Medical University of Innsbruck, 6020, Innsbruck, Austria
| | - Kirstin Hobiger
- Institute of Physiology and Pathophysiology, Philipps-University Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
| | - Angeliki Mavrantoni
- Institute of Physiology and Pathophysiology, Philipps-University Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
| | - Anja Feuer
- Institute of Physiology and Pathophysiology, Philipps-University Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
| | - Johannes Oberwinkler
- Institute of Physiology and Pathophysiology, Philipps-University Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
| | - Dominik Oliver
- Institute of Physiology and Pathophysiology, Philipps-University Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany
- DFG Research Training Group GRK 2213, Membrane Plasticity in Tissue Development and Remodeling, Philipps-University Marburg, 35043, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), Universities of Marburg and Giessen, Marburg/Giessen, Germany
| | - Christian R Halaszovich
- Institute of Physiology and Pathophysiology, Philipps-University Marburg, Deutschhausstr. 1-2, 35037, Marburg, Germany.
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12
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Emadi-Baygi M, Sedighi R, Nourbakhsh N, Nikpour P. Pseudogenes in gastric cancer pathogenesis: a review article. Brief Funct Genomics 2018; 16:348-360. [PMID: 28459995 DOI: 10.1093/bfgp/elx004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cancer burden rises globally at an alarming pace. According to GLOBOCAN 2012, gastric cancer (GC) is regarded as the fifth most common malignancy in the world. Being twice as high in men as in women, GC is the third leading cause of cancer mortality in both sexes globally. Being labeled as 'junk DNA', pseudogenes were considered as nonfunctional 'trash', which contribute nothing to survival of the organism; therefore, a number of strategies have been developed to circumvent their accidental detection. Recent progresses have confirmed that pseudogenes can have broad and multifaceted spectrum of activities in human cancers in general and GC in particular. Furthermore, the mentioned functions are parental gene-dependent and/or -independent. Therefore, pseudogenes can be regarded as the emerging class of elaborate modulators of gene expression involved in pathogenesis of human cancers including gastric adenocarcinoma.
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13
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Lusche DF, Buchele EC, Russell KB, Soll BA, Vitolo MI, Klemme MR, Wessels DJ, Soll DR. Overexpressing TPTE2 ( TPIP), a homolog of the human tumor suppressor gene PTEN, rescues the abnormal phenotype of the PTEN-/- mutant. Oncotarget 2018; 9:21100-21121. [PMID: 29765523 PMCID: PMC5940379 DOI: 10.18632/oncotarget.24941] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/06/2018] [Indexed: 11/25/2022] Open
Abstract
One possible approach to normalize mutant cells that are metastatic and tumorigenic, is to upregulate a functionally similar homolog of the mutated gene. Here we have explored this hypothesis by generating an overexpressor of TPTE2 (TPIP), a homolog of PTEN, in PTEN-/- mutants, the latter generated by targeted mutagenesis of a human epithelial cell line. Overexpression of TPTE2 normalized phenotypic changes associated with the PTEN mutation. The PTEN-/- -associated changes rescued by overexpressing TPTE2 included 1) accelerated wound healing in the presence or absence of added growth factors (GFs), 2) increased division rates on a 2D substrate in the presence of GFs, 3) adhesion and viability on a 2D substrate in the absence of GFs, 4) viability in a 3D Matrigel model in the absence of GFs and substrate adhesion 5) loss of apoptosis-associated annexin V cell surface binding sites. The results justify further exploration into the possibility that upregulating TPTE2 by a drug may reverse metastatic and tumorigenic phenotypes mediated in part by a mutation in PTEN. This strategy may also be applicable to other tumorigenic mutations in which a homolog to the mutated gene is present and can substitute functionally.
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Affiliation(s)
- Daniel F. Lusche
- Developmental Studies Hybridoma Bank and W.M. Keck Dynamic Image Analysis Facility, Department of Biology, The University of Iowa, Iowa City, 52242 IA, USA
| | - Emma C. Buchele
- Developmental Studies Hybridoma Bank and W.M. Keck Dynamic Image Analysis Facility, Department of Biology, The University of Iowa, Iowa City, 52242 IA, USA
| | - Kanoe B. Russell
- Developmental Studies Hybridoma Bank and W.M. Keck Dynamic Image Analysis Facility, Department of Biology, The University of Iowa, Iowa City, 52242 IA, USA
| | - Benjamin A. Soll
- Developmental Studies Hybridoma Bank and W.M. Keck Dynamic Image Analysis Facility, Department of Biology, The University of Iowa, Iowa City, 52242 IA, USA
| | - Michele I. Vitolo
- Greenebaum Cancer Center, The University of Maryland, Baltimore, Maryland, Baltimore, 21201 MD, USA
| | - Michael R. Klemme
- Developmental Studies Hybridoma Bank and W.M. Keck Dynamic Image Analysis Facility, Department of Biology, The University of Iowa, Iowa City, 52242 IA, USA
| | - Deborah J. Wessels
- Developmental Studies Hybridoma Bank and W.M. Keck Dynamic Image Analysis Facility, Department of Biology, The University of Iowa, Iowa City, 52242 IA, USA
| | - David R. Soll
- Developmental Studies Hybridoma Bank and W.M. Keck Dynamic Image Analysis Facility, Department of Biology, The University of Iowa, Iowa City, 52242 IA, USA
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14
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Abstract
In higher eukaryotes, the Tyr phosphorylation status of cellular proteins results from the coordinated action of Protein Tyrosine Kinases (PTKs) and Protein Tyrosine Phosphatases (PTPs). PTPs have emerged as highly regulated enzymes with diverse substrate specificity, and proteins with Tyr-dephosphorylation or Tyr-dephosphorylation-like properties can be clustered as the PTPome. This includes proteins from the PTP superfamily, which display a Cys-based catalytic mechanism, as well as enzymes from other gene families (Asp-based phosphatases, His-based phosphatases) that have converged in protein Tyr-dephosphorylation-related functions by using non-Cys-based catalytic mechanisms. Within the Cys-based members of the PTPome, classical PTPs dephosphorylate specific phosphoTyr (pTyr) residues from protein substrates, whereas VH1-like dual-specificity PTPs dephosphorylate pTyr, pSer, and pThr residues, as well as nonproteinaceous substrates, including phosphoinositides and phosphorylated carbohydrates. In addition, several PTPs have impaired catalytic activity as a result of amino acid substitutions at their active sites, but retain regulatory functions related with pTyr signaling. As a result of their relevant biological activity, many PTPs are linked to human disease, including cancer, neurodevelopmental, and metabolic diseases, making these proteins important drug targets and molecular markers in the clinic. Here, a brief overview on the biochemistry and physiology of the different groups of proteins that belong to the mammalian PTPome is presented.
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15
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Hosono Y, Niknafs YS, Prensner JR, Iyer MK, Dhanasekaran SM, Mehra R, Pitchiaya S, Tien J, Escara-Wilke J, Poliakov A, Chu SC, Saleh S, Sankar K, Su F, Guo S, Qiao Y, Freier SM, Bui HH, Cao X, Malik R, Johnson TM, Beer DG, Feng FY, Zhou W, Chinnaiyan AM. Oncogenic Role of THOR, a Conserved Cancer/Testis Long Non-coding RNA. Cell 2017; 171:1559-1572.e20. [PMID: 29245011 PMCID: PMC5734106 DOI: 10.1016/j.cell.2017.11.040] [Citation(s) in RCA: 177] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 08/29/2017] [Accepted: 11/20/2017] [Indexed: 01/16/2023]
Abstract
Large-scale transcriptome sequencing efforts have vastly expanded the catalog of long non-coding RNAs (lncRNAs) with varying evolutionary conservation, lineage expression, and cancer specificity. Here, we functionally characterize a novel ultraconserved lncRNA, THOR (ENSG00000226856), which exhibits expression exclusively in testis and a broad range of human cancers. THOR knockdown and overexpression in multiple cell lines and animal models alters cell or tumor growth supporting an oncogenic role. We discovered a conserved interaction of THOR with IGF2BP1 and show that THOR contributes to the mRNA stabilization activities of IGF2BP1. Notably, transgenic THOR knockout produced fertilization defects in zebrafish and also conferred a resistance to melanoma onset. Likewise, ectopic expression of human THOR in zebrafish accelerated the onset of melanoma. THOR represents a novel class of functionally important cancer/testis lncRNAs whose structure and function have undergone positive evolutionary selection.
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Affiliation(s)
- Yasuyuki Hosono
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Yashar S Niknafs
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, USA
| | - John R Prensner
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Pediatrics, Boston Children's Hospital, Boston, MA, USA
| | - Matthew K Iyer
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, USA
| | - Saravana M Dhanasekaran
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Rohit Mehra
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | | | - Jean Tien
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | | | - Anton Poliakov
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Shih-Chun Chu
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Sahal Saleh
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Keerthana Sankar
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Fengyun Su
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | | | - Yuanyuan Qiao
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | | | | | - Xuhong Cao
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Rohit Malik
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Pathology, University of Michigan, Ann Arbor, MI, USA
| | - Timothy M Johnson
- Department of Dermatology, University of Michigan Medical School, Ann Arbor, MI, USA; Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - David G Beer
- Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA; Section of Thoracic Surgery, Department of Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Felix Y Feng
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA; Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Weibin Zhou
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA
| | - Arul M Chinnaiyan
- Michigan Center for Translational Pathology, University of Michigan, Ann Arbor, MI, USA; Department of Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, USA; Department of Pathology, University of Michigan, Ann Arbor, MI, USA; Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA; Howard Hughes Medical Institute, University of Michigan, Ann Arbor, MI, USA; Department of Urology, University of Michigan, Ann Arbor, MI, USA.
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16
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Rosasco MG, Gordon SE, Bajjalieh SM. Characterization of the Functional Domains of a Mammalian Voltage-Sensitive Phosphatase. Biophys J 2016; 109:2480-2491. [PMID: 26682807 DOI: 10.1016/j.bpj.2015.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 10/27/2015] [Accepted: 11/03/2015] [Indexed: 12/12/2022] Open
Abstract
Voltage-sensitive phosphatases (VSPs) are proteins that directly couple changes in membrane electrical potential to inositol lipid phosphatase activity. VSPs thus couple two signaling pathways that are critical for cellular functioning. Although a number of nonmammalian VSPs have been characterized biophysically, mammalian VSPs are less well understood at both the physiological and biophysical levels. In this study, we aimed to address this gap in knowledge by determining whether the VSP from mouse, Mm-VSP, is expressed in the brain and contains a functional voltage-sensing domain (VSD) and a phosphatase domain. We report that Mm-VSP is expressed in neurons and is developmentally regulated. To address whether the functions of the VSD and phosphatase domain are retained in Mm-VSP, we took advantage of the modular nature of these domains and expressed each independently as a chimeric protein in a heterologous expression system. We found that the Mm-VSP VSD, fused to a viral potassium channel, was able to drive voltage-dependent gating of the channel pore. The Mm-VSP phosphatase domain, fused to the VSD of a nonmammalian VSP, was also functional: activation resulted in PI(4,5)P2 depletion that was sufficient to inhibit the PI(4,5)P2-regulated KCNQ2/3 channels. While testing the functionality of the VSD and phosphatase domain, we observed slight differences between the activities of Mm-VSP-based chimeras and those of nonmammalian VSPs. Although the properties of VSP chimeras may not completely reflect the properties of native VSPs, the differences we observed in voltage-sensing and phosphatase activity provide a starting point for future experiments to investigate the function of Mm-VSP and other mammalian VSPs. In conclusion, our data reveal that both the VSD and the lipid phosphatase domain of Mm-VSP are functional, indicating that Mm-VSP likely plays an important role in mouse neurophysiology.
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Affiliation(s)
- Mario G Rosasco
- Department of Pharmacology, University of Washington, Seattle, Washington; Department of Physiology and Biophysics, University of Washington, Seattle, Washington
| | - Sharona E Gordon
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington
| | - Sandra M Bajjalieh
- Department of Pharmacology, University of Washington, Seattle, Washington.
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17
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Rudge SA, Wakelam MJO. Phosphatidylinositolphosphate phosphatase activities and cancer. J Lipid Res 2015; 57:176-92. [PMID: 26302980 DOI: 10.1194/jlr.r059154] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Indexed: 12/13/2022] Open
Abstract
Signaling through the phosphoinositide 3-kinase pathways mediates the actions of a plethora of hormones, growth factors, cytokines, and neurotransmitters upon their target cells following receptor occupation. Overactivation of these pathways has been implicated in a number of pathologies, in particular a range of malignancies. The tight regulation of signaling pathways necessitates the involvement of both stimulatory and terminating enzymes; inappropriate activation of a pathway can thus result from activation or inhibition of the two signaling arms. The focus of this review is to discuss, in detail, the activities of the identified families of phosphoinositide phosphatase expressed in humans, and how they regulate the levels of phosphoinositides implicated in promoting malignancy.
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Affiliation(s)
- Simon A Rudge
- Signalling Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom
| | - Michael J O Wakelam
- Signalling Programme, Babraham Institute, Cambridge CB22 3AT, United Kingdom
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18
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Gazy I, Zeevi DA, Renbaum P, Zeligson S, Eini L, Bashari D, Smith Y, Lahad A, Goldberg M, Ginsberg D, Levy-Lahad E. TODRA, a lncRNA at the RAD51 Locus, Is Oppositely Regulated to RAD51, and Enhances RAD51-Dependent DSB (Double Strand Break) Repair. PLoS One 2015; 10:e0134120. [PMID: 26230935 PMCID: PMC4521930 DOI: 10.1371/journal.pone.0134120] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Accepted: 07/06/2015] [Indexed: 12/18/2022] Open
Abstract
Expression of RAD51, a crucial player in homologous recombination (HR) and DNA double-strand break (DSB) repair, is dysregulated in human tumors, and can contribute to genomic instability and tumor progression. To further understand RAD51 regulation we functionally characterized a long non-coding (lnc) RNA, dubbed TODRA (Transcribed in the Opposite Direction of RAD51), transcribed 69bp upstream to RAD51, in the opposite direction. We demonstrate that TODRA is an expressed transcript and that the RAD51 promoter region is bidirectional, supporting TODRA expression (7-fold higher than RAD51 in this assay, p = 0.003). TODRA overexpression in HeLa cells induced expression of TPIP, a member of the TPTE family which includes PTEN. Similar to PTEN, we found that TPIP co-activates E2F1 induction of RAD51. Analysis of E2F1's effect on the bidirectional promoter showed that E2F1 binding to the same site that promotes RAD51 expression, results in downregulation of TODRA. Moreover, TODRA overexpression induces HR in a RAD51-dependent DSB repair assay, and increases formation of DNA damage-induced RAD51-positive foci. Importantly, gene expression in breast tumors supports our finding that E2F1 oppositely regulates RAD51 and TODRA: increased RAD51 expression, which is associated with an aggressive tumor phenotype (e.g. negative correlation with positive ER (r = -0.22, p = 0.02) and positive PR status (r = -0.27, p<0.001); positive correlation with ki67 status (r = 0.36, p = 0.005) and HER2 amplification (r = 0.41, p = 0.001)), correlates as expected with lower TODRA and higher E2F1 expression. However, although E2F1 induction resulted in TPIP downregulation in cell lines, we find that TPIP expression in tumors is not reduced despite higher E2F1 expression, perhaps contributing to increased RAD51 expression. Our results identify TPIP as a novel E2F1 co-activator, suggest a similar role for other TPTEs, and indicate that the TODRA lncRNA affects RAD51 dysregulation and RAD51-dependent DSB repair in malignancy. Importantly, gene expression in breast tumors supports our finding that E2F1 oppositely regulates RAD51 and TODRA: increased RAD51 expression, which is associated with an aggressive tumor phenotype (e.g. negative correlation with positive ER (r = -0.22, p = 0.02) and positive PR status (r = -0.27, p<0.001); positive correlation with ki67 status (r = 0.36, p = 0.005) and HER2 amplification (r = 0.41, p = 0.001)), correlates as expected with lower TODRA and higher E2F1 expression. However, although E2F1 induction resulted in TPIP downregulation in cell lines, we find that TPIP expression in tumors is not reduced despite higher E2F1 expression, perhaps contributing to increased RAD51 expression. Our results identify TPIP as a novel E2F1 co-activator, suggest a similar role for other TPTEs, and indicate that the TODRA lncRNA affects RAD51 dysregulation and RAD51-dependent DSB repair in malignancy.
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Affiliation(s)
- Inbal Gazy
- Human Genetics, Hebrew University Medical School, Jerusalem, Israel
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - David A. Zeevi
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Paul Renbaum
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Sharon Zeligson
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Lital Eini
- Department of Genetics, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dana Bashari
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan, Israel
| | - Yoav Smith
- Genomic Data Analysis Unit, Hebrew University Medical School, Jerusalem, Israel
| | - Amnon Lahad
- Department of Family Medicine, Hebrew University Medical School, Jerusalem, Israel
- Clalit Health Services, Jerusalem, Israel
| | - Michal Goldberg
- Department of Genetics, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Doron Ginsberg
- The Mina and Everard Goodman Faculty of Life Science, Bar Ilan University, Ramat Gan, Israel
| | - Ephrat Levy-Lahad
- Human Genetics, Hebrew University Medical School, Jerusalem, Israel
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel
- * E-mail:
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19
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Abstract
The importance of PTEN in cellular function is underscored by the frequency of its deregulation in cancer. PTEN tumor-suppressor activity depends largely on its lipid phosphatase activity, which opposes PI3K/AKT activation. As such, PTEN regulates many cellular processes, including proliferation, survival, energy metabolism, cellular architecture, and motility. More than a decade of research has expanded our knowledge about how PTEN is controlled at the transcriptional level as well as by numerous posttranscriptional modifications that regulate its enzymatic activity, protein stability, and cellular location. Although the role of PTEN in cancers has long been appreciated, it is also emerging as an important factor in other diseases, such as diabetes and autism spectrum disorders. Our understanding of PTEN function and regulation will hopefully translate into improved prognosis and treatment for patients suffering from these ailments.
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Affiliation(s)
- Carolyn A Worby
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093-0721;
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20
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Hobiger K, Friedrich T. Voltage sensitive phosphatases: emerging kinship to protein tyrosine phosphatases from structure-function research. Front Pharmacol 2015; 6:20. [PMID: 25713537 PMCID: PMC4322731 DOI: 10.3389/fphar.2015.00020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 01/21/2015] [Indexed: 02/03/2023] Open
Abstract
The transmembrane protein Ci-VSP from the ascidian Ciona intestinalis was described as first member of a fascinating family of enzymes, the voltage sensitive phosphatases (VSPs). Ci-VSP and its voltage-activated homologs from other species are stimulated by positive membrane potentials and dephosphorylate the head groups of negatively charged phosphoinositide phosphates (PIPs). In doing so, VSPs act as control centers at the cytosolic membrane surface, because they intervene in signaling cascades that are mediated by PIP lipids. The characteristic motif CX5RT/S in the active site classifies VSPs as members of the huge family of cysteine-based protein tyrosine phosphatases (PTPs). Although PTPs have already been well-characterized regarding both, structure and function, their relationship to VSPs has drawn only limited attention so far. Therefore, the intention of this review is to give a short overview about the extensive knowledge about PTPs in relation to the facts known about VSPs. Here, we concentrate on the structural features of the catalytic domain which are similar between both classes of phosphatases and their consequences for the enzymatic function. By discussing results obtained from crystal structures, molecular dynamics simulations, and mutagenesis studies, a possible mechanism for the catalytic cycle of VSPs is presented based on that one proposed for PTPs. In this way, we want to link the knowledge about the catalytic activity of VSPs and PTPs.
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Affiliation(s)
- Kirstin Hobiger
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps-Universität Marburg Marburg, Germany
| | - Thomas Friedrich
- Max-Volmer-Laboratory of Biophysical Chemistry, Institute of Chemistry, Technische Universität Berlin Berlin, Germany
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21
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Kim S, Rahman MM, Noh K, Lee JJ, Kim YJ. Investigating the Regulatory Interaction of Linker Region of Ciona intestinalis Voltage-sensitive Phosphatase with Lipid Membrane. B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.11.3389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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22
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Lusche DF, Wessels D, Richardson NA, Russell KB, Hanson BM, Soll BA, Lin BH, Soll DR. PTEN redundancy: overexpressing lpten, a homolog of Dictyostelium discoideum ptenA, the ortholog of human PTEN, rescues all behavioral defects of the mutant ptenA-. PLoS One 2014; 9:e108495. [PMID: 25247494 PMCID: PMC4172592 DOI: 10.1371/journal.pone.0108495] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 08/22/2014] [Indexed: 11/18/2022] Open
Abstract
Mutations in the tumor suppressor gene PTEN are associated with a significant proportion of human cancers. Because the human genome also contains several homologs of PTEN, we considered the hypothesis that if a homolog, functionally redundant with PTEN, can be overexpressed, it may rescue the defects of a PTEN mutant. We have performed an initial test of this hypothesis in the model system Dictyostelium discoideum, which contains an ortholog of human PTEN, ptenA. Deletion of ptenA results in defects in motility, chemotaxis, aggregation and multicellular morphogenesis. D. discoideum also contains lpten, a newly discovered homolog of ptenA. Overexpressing lpten completely rescues all developmental and behavioral defects of the D. discoideum mutant ptenA−. This hypothesis must now be tested in human cells.
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Affiliation(s)
- Daniel F. Lusche
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Deborah Wessels
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Nicole A. Richardson
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Kanoe B. Russell
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Brett M. Hanson
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Benjamin A. Soll
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - Benjamin H. Lin
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
| | - David R. Soll
- Monoclonal Antibody Research Institute and Developmental Studies Hybridoma Bank, Department of Biology, The University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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23
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Kim IH, Hevezi P, Varga C, Pathak MM, Hong L, Ta D, Tran CT, Zlotnik A, Soltesz I, Tombola F. Evidence for functional diversity between the voltage-gated proton channel Hv1 and its closest related protein HVRP1. PLoS One 2014; 9:e105926. [PMID: 25165868 PMCID: PMC4148356 DOI: 10.1371/journal.pone.0105926] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 07/25/2014] [Indexed: 11/18/2022] Open
Abstract
The Hv1 channel and voltage-sensitive phosphatases share with voltage-gated sodium, potassium, and calcium channels the ability to detect changes in membrane potential through voltage-sensing domains (VSDs). However, they lack the pore domain typical of these other channels. NaV, KV, and CaV proteins can be found in neurons and muscles, where they play important roles in electrical excitability. In contrast, VSD-containing proteins lacking a pore domain are found in non-excitable cells and are not involved in neuronal signaling. Here, we report the identification of HVRP1, a protein related to the Hv1 channel (from which the name Hv1 Related Protein 1 is derived), which we find to be expressed primarily in the central nervous system, and particularly in the cerebellum. Within the cerebellar tissue, HVRP1 is specifically expressed in granule neurons, as determined by in situ hybridization and immunohistochemistry. Analysis of subcellular distribution via electron microscopy and immunogold labeling reveals that the protein localizes on the post-synaptic side of contacts between glutamatergic mossy fibers and the granule cells. We also find that, despite the similarities in amino acid sequence and structural organization between Hv1 and HVRP1, the two proteins have distinct functional properties. The high conservation of HVRP1 in vertebrates and its cellular and subcellular localizations suggest an important function in the nervous system.
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Affiliation(s)
- Iris H. Kim
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Peter Hevezi
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Csaba Varga
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, California, United States of America
| | - Medha M. Pathak
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Liang Hong
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Dennis Ta
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Chau T. Tran
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Albert Zlotnik
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
| | - Ivan Soltesz
- Department of Anatomy and Neurobiology, University of California Irvine, Irvine, California, United States of America
| | - Francesco Tombola
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States of America
- * E-mail:
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24
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Smith JF, Yango P, Altman E, Choudhry S, Poelzl A, Zamah AM, Rosen M, Klatsky PC, Tran ND. Testicular niche required for human spermatogonial stem cell expansion. Stem Cells Transl Med 2014; 3:1043-54. [PMID: 25038247 DOI: 10.5966/sctm.2014-0045] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Prepubertal boys treated with high-dose chemotherapy do not have an established means of fertility preservation because no established in vitro technique exists to expand and mature purified spermatogonial stem cells (SSCs) to functional sperm in humans. In this study, we define and characterize the unique testicular cellular niche required for SSC expansion using testicular tissues from men with normal spermatogenesis. Highly purified SSCs and testicular somatic cells were isolated by fluorescence-activated cell sorting using SSEA-4 and THY1 as markers of SSCs and somatic cells. Cells were cultured on various established niches to assess their role in SSC expansion in a defined somatic cellular niche. Of all the niches examined, cells in the SSEA-4 population exclusively bound to adult testicular stromal cells, established colonies, and expanded. Further characterization of these testicular stromal cells revealed distinct mesenchymal markers and the ability to undergo differentiation along the mesenchymal lineage, supporting a testicular multipotent stromal cell origin. In vitro human SSC expansion requires a unique niche provided exclusively by testicular multipotent stromal cells with mesenchymal properties. These findings provide an important foundation for developing methods of inducing SSC growth and maturation in prepubertal testicular tissue, essential to enabling fertility preservation for these boys.
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Affiliation(s)
- James F Smith
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
| | - Pamela Yango
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
| | - Eran Altman
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
| | - Shweta Choudhry
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
| | - Andrea Poelzl
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
| | - Alberuni M Zamah
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
| | - Mitchell Rosen
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
| | - Peter C Klatsky
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
| | - Nam D Tran
- Departments of Urology and Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, San Francisco, California, USA; Helen Schneider Hospital for Women, Rabin Medical Center, Petah-Tiqva, Israel; Department of Obstetrics and Gynecology, Albert Einstein University, Bronx, New York, USA
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25
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Mutua J, Jinno Y, Sakata S, Okochi Y, Ueno S, Tsutsui H, Kawai T, Iwao Y, Okamura Y. Functional diversity of voltage-sensing phosphatases in two urodele amphibians. Physiol Rep 2014; 2:e12061. [PMID: 25347851 PMCID: PMC4187576 DOI: 10.14814/phy2.12061] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Voltage-sensing phosphatases (VSPs) share the molecular architecture of the voltage sensor domain (VSD) with voltage-gated ion channels and the phosphoinositide phosphatase region with the phosphatase and tensin homolog (PTEN), respectively. VSPs enzymatic activities are regulated by the motions of VSD upon depolarization. The physiological role of these proteins has remained elusive, and insights may be gained by investigating biological variations in different animal species. Urodele amphibians are vertebrates with potent activities of regeneration and also show diverse mechanisms of polyspermy prevention. We cloned cDNAs of VSPs from the testes of two urodeles; Hynobius nebulosus and Cynops pyrrhogaster, and compared their expression and voltage-dependent activation. Their molecular architecture is highly conserved in both Hynobius VSP (Hn-VSP) and Cynops VSP (Cp-VSP), including the positively-charged arginine residues in the S4 segment of the VSD and the enzymatic active site for substrate binding, yet the C-terminal C2 domain of Hn-VSP is significantly shorter than that of Cp-VSP and other VSP orthologs. RT-PCR analysis showed that gene expression pattern was distinct between two VSPs. The voltage sensor motions and voltage-dependent phosphatase activities were investigated electrophysiologically by expression in Xenopus oocytes. Both VSPs showed "sensing" currents, indicating that their voltage sensor domains are functional. The phosphatase activity of Cp-VSP was found to be voltage dependent, as shown by its ability to regulate the conductance of coexpressed GIRK2 channels, but Hn-VSP lacked such phosphatase activity due to the truncation of its C2 domain.
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Affiliation(s)
- Joshua Mutua
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan
| | - Yuka Jinno
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Souhei Sakata
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Yoshifumi Okochi
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Shuichi Ueno
- Laboratory of Molecular Developmental Biology, Department of Applied Molecular Biosciences, Graduate School of Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Hidekazu Tsutsui
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Takafumi Kawai
- Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Yasuhiro Iwao
- Laboratory of Molecular Developmental Biology, Department of Applied Molecular Biosciences, Graduate School of Medicine, Yamaguchi University, Yamaguchi, Japan
| | - Yasushi Okamura
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, Japan Laboratory of Integrative Physiology, Department of Physiology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
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26
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Kalli AC, Devaney I, Sansom MSP. Interactions of phosphatase and tensin homologue (PTEN) proteins with phosphatidylinositol phosphates: insights from molecular dynamics simulations of PTEN and voltage sensitive phosphatase. Biochemistry 2014; 53:1724-32. [PMID: 24588644 PMCID: PMC4167384 DOI: 10.1021/bi5000299] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
![]()
The
phosphatase and tensin homologue (PTEN) and the Ciona
intestinalis voltage sensitive phosphatase (Ci-VSP) are both
phosphatidylinositol phosphate (PIP) phosphatases that contain a C2
domain. PTEN is a tumor suppressor protein that acts as a phosphatase
on PIP3 in mammalian cell membranes. It contains two principal
domains:
a phosphatase domain (PD) and a C2 domain. Despite detailed structural
and functional characterization, less is known about its mechanism
of interaction with PIP-containing lipid bilayers. Ci-VSP consists
of an N-terminal transmembrane voltage sensor domain and a C-terminal
PTEN domain, which in turn contains a PD and a C2 domain. The nature
of the interaction of the PTEN domain of Ci-VSP with membranes has
not been well established. We have used multiscale molecular dynamics
simulations to define the interaction mechanisms
of PTEN and of the Ci-VSP PTEN domains with PIP-containing lipid bilayers.
Our results suggest a novel mechanism of association of the PTEN with
such bilayers, in which an initial electrostatics-driven encounter
of the protein and bilayer is followed by reorientation of the protein
to optimize its interactions with PIP molecules in the membrane. Although
a PIP3 molecule binds close to the active site of PTEN,
our simulations suggest a further conformational change of the protein
may be required for catalytically productive binding to occur. Ci-VSP
interacted with membranes in an orientation comparable to that of
PTEN but bound directly to PIP-containing membranes without a subsequent
reorientation step. Again, PIP3 bound close to the active
site of the Ci-VSP PD, but not in a catalytically productive manner.
Interactions of Ci-VSP with the bilayer induced clustering of PIP
molecules around the protein.
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Affiliation(s)
- Antreas C Kalli
- Department of Biochemistry, University of Oxford , South Parks Road, Oxford OX1 3QU, U.K
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27
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Djureinovic D, Fagerberg L, Hallström B, Danielsson A, Lindskog C, Uhlén M, Pontén F. The human testis-specific proteome defined by transcriptomics and antibody-based profiling. Mol Hum Reprod 2014; 20:476-88. [PMID: 24598113 DOI: 10.1093/molehr/gau018] [Citation(s) in RCA: 140] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The testis' function is to produce haploid germ cells necessary for reproduction. Here we have combined a genome-wide transcriptomics analysis with immunohistochemistry-based protein profiling to characterize the molecular components of the testis. Deep sequencing (RNA-Seq) of normal human testicular tissue from seven individuals was performed and compared with 26 other normal human tissue types. All 20 050 putative human genes were classified into categories based on expression patterns. The analysis shows that testis is the tissue with the most tissue-specific genes by far. More than 1000 genes show a testis-enriched expression pattern in testis when compared with all other analyzed tissues. Highly testis enriched genes were further characterized with respect to protein localization within the testis, such as spermatogonia, spermatocytes, spermatids, sperm, Sertoli cells and Leydig cells. Here we present an immunohistochemistry-based analysis, showing the localization of corresponding proteins in different cell types and various stages of spermatogenesis, for 62 genes expressed at >50-fold higher levels in testis when compared with other tissues. A large fraction of these genes were unexpectedly expressed in early stages of spermatogenesis. In conclusion, we have applied a genome-wide analysis to identify the human testis-specific proteome using transcriptomics and antibody-based protein profiling, providing lists of genes expressed in a tissue-enriched manner in the testis. The majority of these genes and proteins were previously poorly characterised in terms of localization and function, and our list provides an important starting point to increase our molecular understanding of human reproductive biology and disease.
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Affiliation(s)
- D Djureinovic
- Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala SE-751 85, Sweden Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala SE-751 85, Sweden
| | - L Fagerberg
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm SE-171 21, Sweden
| | - B Hallström
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm SE-171 21, Sweden
| | - A Danielsson
- Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala SE-751 85, Sweden Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala SE-751 85, Sweden
| | - C Lindskog
- Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala SE-751 85, Sweden Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala SE-751 85, Sweden
| | - M Uhlén
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm SE-171 21, Sweden
| | - F Pontén
- Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala SE-751 85, Sweden Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala SE-751 85, Sweden
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28
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Rousseaux S, Debernardi A, Jacquiau B, Vitte AL, Vesin A, Nagy-Mignotte H, Moro-Sibilot D, Brichon PY, Lantuejoul S, Hainaut P, Laffaire J, de Reyniès A, Beer DG, Timsit JF, Brambilla C, Brambilla E, Khochbin S. Ectopic activation of germline and placental genes identifies aggressive metastasis-prone lung cancers. Sci Transl Med 2014; 5:186ra66. [PMID: 23698379 DOI: 10.1126/scitranslmed.3005723] [Citation(s) in RCA: 362] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Activation of normally silent tissue-specific genes and the resulting cell "identity crisis" are the unexplored consequences of malignant epigenetic reprogramming. We designed a strategy for investigating this reprogramming, which consisted of identifying a large number of tissue-restricted genes that are epigenetically silenced in normal somatic cells and then detecting their expression in cancer. This approach led to the demonstration that large-scale "off-context" gene activations systematically occur in a variety of cancer types. In our series of 293 lung tumors, we identified an ectopic gene expression signature associated with a subset of highly aggressive tumors, which predicted poor prognosis independently of the TNM (tumor size, node positivity, and metastasis) stage or histological subtype. The ability to isolate these tumors allowed us to reveal their common molecular features characterized by the acquisition of embryonic stem cell/germ cell gene expression profiles and the down-regulation of immune response genes. The methodical recognition of ectopic gene activations in cancer cells could serve as a basis for gene signature-guided tumor stratification, as well as for the discovery of oncogenic mechanisms, and expand the understanding of the biology of very aggressive tumors.
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Affiliation(s)
- Sophie Rousseaux
- INSERM, U823, Université Joseph Fourier, Grenoble 1, Institut Albert Bonniot, Grenoble F-38700, France.
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29
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Pagotto A, Caballero OL, Volkmar N, Devalle S, Simpson AJG, Lu X, Christianson JC. Centrosomal localisation of the cancer/testis (CT) antigens NY-ESO-1 and MAGE-C1 is regulated by proteasome activity in tumour cells. PLoS One 2013; 8:e83212. [PMID: 24340093 PMCID: PMC3858345 DOI: 10.1371/journal.pone.0083212] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 10/31/2013] [Indexed: 02/03/2023] Open
Abstract
The Cancer/Testis (CT) antigen family of genes are transcriptionally repressed in most human tissues but are atypically re-expressed in many malignant tumour types. Their restricted expression profile makes CT antigens ideal targets for cancer immunotherapy. As little is known about whether CT antigens may be regulated by post-translational processing, we investigated the mechanisms governing degradation of NY-ESO-1 and MAGE-C1 in selected cancer cell lines. Inhibitors of proteasome-mediated degradation induced the partitioning of NY-ESO-1 and MAGE-C1 into a detergent insoluble fraction. Moreover, this treatment also resulted in increased localisation of NY-ESO-1 and MAGE-C1 at the centrosome. Despite their interaction, relocation of either NY-ESO-1 or MAGE-C1 to the centrosome could occur independently of each other. Using a series of truncated fragments, the regions corresponding to NY-ESO-191-150 and MAGE-C1900-1116 were established as important for controlling both stability and localisation of these CT antigens. Our findings demonstrate that the steady state levels of NY-ESO-1 and MAGE-C1 are regulated by proteasomal degradation and that both behave as aggregation-prone proteins upon accumulation. With proteasome inhibitors being increasingly used as front-line treatment in cancer, these data raise issues about CT antigen processing for antigenic presentation and therefore immunogenicity in cancer patients.
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Affiliation(s)
- Anna Pagotto
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Headington, Oxford, United Kingdom
| | - Otavia L. Caballero
- Ludwig Collaborative Group, Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Norbert Volkmar
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Headington, Oxford, United Kingdom
| | - Sylvie Devalle
- Ludwig Institute for Cancer Research, New York Branch at Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Andrew J. G. Simpson
- Ludwig Collaborative Group, Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Xin Lu
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Headington, Oxford, United Kingdom
- * E-mail:
| | - John C. Christianson
- Ludwig Institute for Cancer Research, Nuffield Department of Clinical Medicine, University of Oxford, Headington, Oxford, United Kingdom
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30
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Abstract
Phosphoinositides are the phosphorylated derivatives of phosphatidylinositol, and play a very significant role in a diverse range of signaling processes in eukaryotic cells. A number of phosphoinositide-metabolizing enzymes, including phosphoinositide-kinases and phosphatases are involved in the synthesis and degradation of these phospholipids. Recently, the function of various phosphatases in the phosphatidylinositol signaling pathway has been of great interest. In the present review we summarize the structural insights and biochemistry of various phosphatases in regulating phosphoinositide metabolism.
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Affiliation(s)
- Young Jun Kim
- Department of Biotechnology, Konkuk University, Chungju, Korea
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31
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Pulido R, Stoker AW, Hendriks WJAJ. PTPs emerge as PIPs: protein tyrosine phosphatases with lipid-phosphatase activities in human disease. Hum Mol Genet 2013; 22:R66-76. [PMID: 23900072 DOI: 10.1093/hmg/ddt347] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein tyrosine phosphatases (PTPs) constitute a family of key homeostatic regulators, with wide implications on physiology and disease. Recent findings have unveiled that the biological activity of PTPs goes beyond the dephosphorylation of phospho-proteins to shut down protein tyrosine kinase-driven signaling cascades. Substrates dephosphorylated by clinically relevant PTPs extend to phospholipids and phosphorylated carbohydrates as well. In addition, non-catalytic functions are also used by PTPs to regulate essential cellular functions. Consequently, PTPs have emerged as novel potential therapeutic targets for human diseases, including cancer predispositions, myopathies and neuropathies. In this review, we highlight recent advances on the multifaceted role of lipid-phosphatase PTPs in human pathology, with an emphasis on hereditary diseases. The involved PTP regulatory networks and PTP modulatory strategies with potential therapeutic application are discussed.
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32
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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33
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Villalba-Galea CA. Voltage-Controlled Enzymes: The New JanusBifrons. Front Pharmacol 2012; 3:161. [PMID: 22993507 PMCID: PMC3440755 DOI: 10.3389/fphar.2012.00161] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2012] [Accepted: 08/19/2012] [Indexed: 12/25/2022] Open
Abstract
The Ciona intestinalis voltage-sensitive phosphatase, Ci-VSP, was the first Voltage-controlled Enzyme (VEnz) proven to be under direct command of the membrane potential. The discovery of Ci-VSP conjugated voltage sensitivity and enzymatic activity in a single protein. These two facets of Ci-VSP activity have provided a unique model for studying how membrane potential is sensed by proteins and a novel mechanism for control of enzymatic activity. These facets make Ci-VSP a fascinating and versatile enzyme. Ci-VSP has a voltage sensing domain (VSD) that resembles those found in voltage-gated channels (VGC). The VSD resides in the N-terminus and is formed by four putative transmembrane segments. The fourth segment contains charged residues which are likely involved in voltage sensing. Ci-VSP produces sensing currents in response to changes in potential, within a defined range of voltages. Sensing currents are analogous to “gating” currents in VGC. As known, these latter proteins contain four VSDs which are entangled in a complex interaction with the pore domain – the effector domain in VGC. This complexity makes studying the basis of voltage sensing in VGC a difficult enterprise. In contrast, Ci-VSP is thought to be monomeric and its catalytic domain – the VSP’s effector domain – can be cleaved off without disrupting the basic electrical functioning of the VSD. For these reasons, VSPs are considered a great model for studying the activity of a VSD in isolation. Finally, VSPs are also phosphoinositide phosphatases. Phosphoinositides are signaling lipids found in eukaryotes and are involved in many processes, including modulation of VGC activity and regulation of cell proliferation. Understanding VSPs as enzymes has been the center of attention in recent years and several reviews has been dedicated to this area. Thus, this review will be focused instead on the other face of this true JanusBifrons and recapitulate what is known about VSPs as electrically active proteins.
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Affiliation(s)
- Carlos A Villalba-Galea
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine Richmond, VA, USA
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34
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Halaszovich CR, Leitner MG, Mavrantoni A, Le A, Frezza L, Feuer A, Schreiber DN, Villalba-Galea CA, Oliver D. A human phospholipid phosphatase activated by a transmembrane control module. J Lipid Res 2012; 53:2266-74. [PMID: 22896666 DOI: 10.1194/jlr.m026021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
In voltage-sensitive phosphatases (VSPs), a transmembrane voltage sensor domain (VSD) controls an intracellular phosphoinositide phosphatase domain, thereby enabling immediate initiation of intracellular signals by membrane depolarization. The existence of such a mechanism in mammals has remained elusive, despite the presence of VSP-homologous proteins in mammalian cells, in particular in sperm precursor cells. Here we demonstrate activation of a human VSP (hVSP1/TPIP) by an intramolecular switch. By engineering a chimeric hVSP1 with enhanced plasma membrane targeting containing the VSD of a prototypic invertebrate VSP, we show that hVSP1 is a phosphoinositide-5-phosphatase whose predominant substrate is PI(4,5)P(2). In the chimera, enzymatic activity is controlled by membrane potential via hVSP1's endogenous phosphoinositide binding motif. These findings suggest that the endogenous VSD of hVSP1 is a control module that initiates signaling through the phosphatase domain and indicate a role for VSP-mediated phosphoinositide signaling in mammals.
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Affiliation(s)
- Christian R Halaszovich
- Institute of Physiology and Pathophysiology, Philipps-Universität Marburg, 35037 Marburg, Germany
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35
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New insights in the activity of voltage sensitive phosphatases. Cell Signal 2012; 24:1541-7. [PMID: 22481094 DOI: 10.1016/j.cellsig.2012.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 03/13/2012] [Accepted: 03/20/2012] [Indexed: 11/23/2022]
Abstract
The Ciona intestinalis voltage sensitive phosphatase (Ci-VSP) was the first proven enzyme to be under direct control of the membrane potential. Ci-VSP belongs to a family of proteins known as Protein Tyrosine Phosphatases (PTP), which are a group of enzymes that catalyze the removal of phosphate groups from phosphatidylinositides and phosphorylated tyrosine residues on proteins. What makes Ci-VSP and similar phosphatases unique is the presence of a Voltage Sensing Domain (VSD) in their N-terminus. The VSD of Ci-VSP shares high homology with those from voltage-gated channels and confers voltage sensitivity to these enzymes. The catalytic domain of Ci-VSP displays extraordinary structural and functional similarities to PTEN. This latter protein is encoded by the Phosphatase and Tensin homolog deleted from chromosome 10 gene, thus its name, and it is known as a tumor suppressor. The resemblance between these proteins has prompted the use of PTEN as a template for the study of Ci-VSP and produced a rapid advance in our understanding of the mechanism of activity of Ci-VSP. This review will be focused on discussing recent advances in the understanding of the activation mechanism for these molecules known as electrochemical coupling.
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36
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Hobiger K, Utesch T, Mroginski MA, Friedrich T. Coupling of Ci-VSP modules requires a combination of structure and electrostatics within the linker. Biophys J 2012; 102:1313-22. [PMID: 22455914 DOI: 10.1016/j.bpj.2012.02.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 02/01/2012] [Accepted: 02/08/2012] [Indexed: 11/26/2022] Open
Abstract
The voltage-sensitive phosphatase Ci-VSP consists of an intracellular phosphatase domain (PD) coupled to a transmembrane voltage-sensor domain (VSD). Depolarization triggers the selective dephosphorylation of phosphoinositides. However, the molecular mechanisms of coupling are still elusive. To clarify the role of the VSD-PD linker as a putative partner for electrostatic interactions with the membrane, we carried out a cysteine-scanning mutagenesis of the whole motif M240-K257. Upon coexpression with PI(4,5)P(2)-sensitive KCNQ2/KCNQ3 channels in Xenopus oocytes, we identified four positions (A242C, R245C, K252C, and Y255C) with a completely abrogated PD activity. Because the mutation effect occurred periodically, we hypothesize that α-helical elements exist within the linker, with a gap near position S249. The combination of these results with the analysis of transient sensing currents of the VSD revealed distinct roles for the N-terminal (M240-S249) and C-terminal (Q250-K257) linker motifs in the VSD-PD coupling. According to our functional results, the computational structure prediction of the Q239-D258 fragment confirmed α-helical structures within the linker, with a short β-turn around S249 in the activated conformation. Remarkably, the position K252 may be a candidate for interacting with the PD rather than for binding to the membrane. This provides the first insight (to our knowledge) into the direct intervention of the linker in the VSD-PD coupling process.
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Affiliation(s)
- Kirstin Hobiger
- Berlin Institute of Technology, Institute of Chemistry, Max-Volmer-Laboratory of Biophysical Chemistry, Berlin, Germany.
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37
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Sutton KA, Jungnickel MK, Jovine L, Florman HM. Evolution of the voltage sensor domain of the voltage-sensitive phosphoinositide phosphatase VSP/TPTE suggests a role as a proton channel in eutherian mammals. Mol Biol Evol 2012; 29:2147-55. [PMID: 22396523 DOI: 10.1093/molbev/mss083] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The voltage-sensitive phosphoinositide phosphatases provide a mechanism to couple changes in the transmembrane electrical potential to intracellular signal transduction pathways. These proteins share a domain architecture that is conserved in deuterostomes. However, gene duplication events in primates, including humans, give rise to the paralogs TPTE and TPTE2 that retain protein domain organization but, in the case of TPTE, have lost catalytic activity. Here, we present evidence that these human proteins contain a functional voltage sensor, similar to that in nonmammalian orthologs. However, domains of these human proteins can also generate a noninactivating outward current that is not observed in zebra fish or tunicate orthologs. This outward current has the anticipated characteristics of a voltage-sensitive proton current and is due to the appearance of a single histidine residue in the S4 transmembrane segment of the voltage sensor. Histidine is observed at this position only during the eutherian radiation. Domains from both human paralogs generate proton currents. This apparent gain of proton channel function during the evolution of the TPTE protein family may account for the conservation of voltage sensor domains despite the loss of phosphatase activity in some human paralogs.
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Affiliation(s)
- Keith A Sutton
- Department of Cell Biology, University of Massachusetts Medical School, MA, USA
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38
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Cell cycle arrest and apoptosis by expression of a novel TPIP (TPIP-C2) cDNA encoding a C2-domain in HEK-293 cells. Mol Biol Rep 2012; 39:7389-402. [PMID: 22311048 DOI: 10.1007/s11033-012-1571-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 01/25/2012] [Indexed: 12/15/2022]
Abstract
The human TPIP (TPTE and PTEN homologous Inositol lipid Phosphatase) belongs to the PTEN (Phosphatase and TENsin homologue deleted on chromosome 10) family of dual-specific phosphatases and is expressed from the human chromosome 13 as multiple splice-variants, e.g., TPIPα, β, γ mRNAs. PTEN is a well characterized tumor suppressor, which controls survival, adhesion, motility and migration of mammalian cells, its C2-domain plays crucial role in controlling these functions. However, role of isolated C2-domain protein in regulation of cell proliferation and apoptosis is not reported. We report sequence analysis and function of a novel human TPIP (TPIP-C2) cDNA encoding a 193 amino acid C2-domain in cell proliferation and apoptosis regulation. In silico analysis and homology modelling revealed that the C2-domain of TPIP-C2 is similar to that of PTEN but with short disorder sequences overlapping or adjacent to the post-translational modification sites. Overexpression of TPIP-C2 cDNA in human embryonic kidney (HEK-293) cells caused cell cycle arrest, inhibition of cell proliferation and induced apoptosis in an activated caspase 3 and PARP-dependent manner in comparison to overexpression of the full length human PTEN cDNA. TPIP-C2 overexpressed cells also showed S-phase cell cycle arrest. We suggest that C2-domain of TPIP-C2 may act as a dominant negative effector, which may bind to and arrest the cell proliferation signalling complex and isolated TPIP-C2-domain-like proteins expressed in mammalian cells/tissues may play important role in regulation of cell proliferation and apoptosis. The TPIP-C2 cDNA may be exploited for inducing cell cycle-inhibition and apoptosis in human cancer cells and tissues.
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Mishra RR, Chaudhary JK, Bajaj GD, Rath PC. A novel human TPIP splice-variant (TPIP-C2) mRNA, expressed in human and mouse tissues, strongly inhibits cell growth in HeLa cells. PLoS One 2011; 6:e28433. [PMID: 22164291 PMCID: PMC3229583 DOI: 10.1371/journal.pone.0028433] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 11/08/2011] [Indexed: 11/23/2022] Open
Abstract
Alternative splicing of mRNAs is known to involve a major regulation of gene expression at RNA level in mammalian cells. The PTEN (Phosphatase and TENsin homologue deleted from the human chromosome 10), TPTE (Transmembrane Phosphatase with TEnsin homology) and TPIP (TPTE and PTEN homologous Inositol lipid Phosphatase) belong to a family of dual-specific lipid and protein phosphatases. PTEN is a well characterized tumor suppressor, which plays crucial role in cell survival, cell cycle regulation, cell proliferation as well as adhesion, motility and migration of cells. The C2-domain of PTEN is essential for PTEN-functions. We have isolated a novel 1019 bp human TPIP cDNA (TPIP-C2) from a human testis cDNA library. In silico analysis of the cDNA revealed that it is produced from the TPIP-locus on the human chromosome 13 by alternative RNA-splicing. It has a unique 5′-Alu sequence, a LINE sequence followed by a 582 bp Open Reading Frame (ORF) encoding a 193 aa polypeptide with a partial phosphatase domain and a C2-domain. TPIP-C2 mRNA is expressed in human testis and in mouse tissues. Mouse testis and brain showed higher levels of TPIP-C2 mRNA in comparison to the heart, liver and kidney under normal physiological conditions. TPIP-C2 mRNAs from human and mouse testes show extensive sequence identity. Over-expression of TPIP-C2 cDNA in HeLa cells strongly (up to 85%) inhibited cell growth/proliferation and caused apoptosis in a caspase 3-dependent manner. These findings suggest for the first time that a TPIP splice-variant mRNA with a partial phosphatase domain and a C2-domain is expressed in cells and tissues of human and murine origins under normal physiological conditions. Inhibition of cell growth/proliferation and induction of apoptosis by overexpression of TPIP-C2 mRNA in HeLa cells suggest that it may be involved in negative regulation of cell growth/proliferation.
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Affiliation(s)
- Rasmi Rekha Mishra
- Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Jitendra Kumar Chaudhary
- Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Gagan Deep Bajaj
- Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Pramod C. Rath
- Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
- * E-mail:
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Ratzan WJ, Evsikov AV, Okamura Y, Jaffe LA. Voltage sensitive phosphoinositide phosphatases of Xenopus: their tissue distribution and voltage dependence. J Cell Physiol 2011; 226:2740-6. [PMID: 21618529 PMCID: PMC3181042 DOI: 10.1002/jcp.22854] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Voltage-sensitive phosphatases (VSPs) are unique proteins in which membrane potential controls enzyme activity. They are comprised of the voltage sensor domain of an ion channel coupled to a lipid phosphatase specific for phosphoinositides, and for ascidian and zebrafish VSPs, the phosphatase activity has been found to be activated by membrane depolarization. The physiological functions of these proteins are unknown, but their expression in testis and embryos suggests a role in fertilization or development. Here we investigate the expression pattern and voltage dependence of VSPs in two frog species, Xenopus laevis and Xenopus tropicalis, that are well suited for experimental studies of these possible functions. X. laevis has two VSP genes (Xl-VSP1 and Xl-VSP2), whereas X. tropicalis has only one gene (Xt-VSP). The highest expression of these genes was observed in testis, ovary, liver, and kidney. Our results show that while Xl-VSP2 activates only at positive membrane potentials outside of the physiological range, Xl-VSP1 and Xt-VSP phosphatase activity is regulated in the voltage range that regulates sperm-egg fusion at fertilization.
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Affiliation(s)
- William J. Ratzan
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
| | | | | | - Laurinda A. Jaffe
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT, USA
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Rodríguez-Escudero I, Oliver MD, Andrés-Pons A, Molina M, Cid VJ, Pulido R. A comprehensive functional analysis of PTEN mutations: implications in tumor- and autism-related syndromes. Hum Mol Genet 2011; 20:4132-42. [PMID: 21828076 DOI: 10.1093/hmg/ddr337] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The PTEN (phosphatase and tensin homolog) phosphatase is unique in mammals in terms of its tumor suppressor activity, exerted by dephosphorylation of the lipid second messenger PIP(3) (phosphatidylinositol 3,4,5-trisphosphate), which activates the phosphoinositide 3-kinase/Akt/mTOR (mammalian target of rapamycin) oncogenic pathway. Loss-of-function mutations in the PTEN gene are frequent in human cancer and in the germline of patients with PTEN hamartoma tumor-related syndromes (PHTSs). In addition, PTEN is mutated in patients with autism spectrum disorders (ASDs), although no functional information on these mutations is available. Here, we report a comprehensive in vivo functional analysis of human PTEN using a heterologous yeast reconstitution system. Ala-scanning mutagenesis at the catalytic loops of PTEN outlined the critical role of residues within the P-catalytic loop for PIP(3) phosphatase activity in vivo. PTEN mutations that mimic the P-catalytic loop of mammalian PTEN-like proteins (TPTE, TPIP, tensins and auxilins) affected PTEN function variably, whereas tumor- or PHTS-associated mutations targeting the PTEN P-loop produced complete loss of function. Conversely, Ala-substitutions, as well as tumor-related mutations at the WPD- and TI-catalytic loops, displayed partial activity in many cases. Interestingly, a tumor-related D92N mutation was partially active, supporting the notion that the PTEN Asp92 residue might not function as the catalytic general acid. The analysis of a panel of ASD-associated hereditary PTEN mutations revealed that most of them did not substantially abrogate PTEN activity in vivo, whereas most of PHTS-associated mutations did. Our findings reveal distinctive functional patterns among PTEN mutations found in tumors and in the germline of PHTS and ASD patients, which could be relevant for therapy.
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Affiliation(s)
- Isabel Rodríguez-Escudero
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Instituto Ramón y Cajal de Investigaciones Sanitarias, Plaza de Ramón y Cajal s/n, 28040 Madrid, Spain
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Abstract
Motile cilia in the airway epithelium are the engine for mucociliary clearance, the mechanism responsible for cleaning the airways from inhaled particles. Human airway epithelial cilia appear to have a slow constitutive rate of beating, driven by inherent and spontaneous dynein ATPase activity. Additionally, cilia can increase their beating frequency by activation of several different control mechanisms. One of these controllers is calcium. Its intracellular concentration is regulated by purinergic and acetylcholine receptors. Besides the rate regulatory effect of calcium on ciliary beat, calcium is also involved in synchronizing the beat among cilia of one single cell as well as between cilia on different cells. This article gives an overview of the complex effects of calcium on the beating of motile cilia in the airways.
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Brun ME, Lana E, Rivals I, Lefranc G, Sarda P, Claustres M, Mégarbané A, De Sario A. Heterochromatic genes undergo epigenetic changes and escape silencing in immunodeficiency, centromeric instability, facial anomalies (ICF) syndrome. PLoS One 2011; 6:e19464. [PMID: 21559330 PMCID: PMC3084872 DOI: 10.1371/journal.pone.0019464] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 03/30/2011] [Indexed: 12/01/2022] Open
Abstract
Immunodeficiency, Centromeric Instability, Facial Anomalies (ICF) syndrome is a rare autosomal recessive disorder that is characterized by a marked immunodeficiency, severe hypomethylation of the classical satellites 2 and 3 associated with disruption of constitutive heterochromatin, and facial anomalies. Sixty percent of ICF patients have mutations in the DNMT3B (DNA methyltransferase 3B) gene, encoding a de novo DNA methyltransferase. In the present study, we have shown that, in ICF lymphoblasts and peripheral blood, juxtacentromeric heterochromatic genes undergo dramatic changes in DNA methylation, indicating that they are bona fide targets of the DNMT3B protein. DNA methylation in heterochromatic genes dropped from about 80% in normal cells to approximately 30% in ICF cells. Hypomethylation was observed in five ICF patients and was associated with activation of these silent genes. Although DNA hypomethylation occurred in all the analyzed heterochromatic genes and in all the ICF patients, gene expression was restricted to some genes, every patient having his own group of activated genes. Histone modifications were preserved in ICF patients. Heterochromatic genes were associated with histone modifications that are typical of inactive chromatin: they had low acetylation on H3 and H4 histones and were slightly enriched in H3K9Me(3), both in ICF and controls. This was also the case for those heterochromatic genes that escaped silencing. This finding suggests that gene activation was not generalized to all the cells, but rather was restricted to a clonal cell population that may contribute to the phenotypic variability observed in ICF syndrome. A slight increase in H3K27 monomethylation was observed both in heterochromatin and active euchromatin in ICF patients; however, no correlation between this modification and activation of heterochromatic genes was found.
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Affiliation(s)
| | - Erica Lana
- INSERM U827, Montpellier, France
- Université Montpellier 1, Montpellier, France
| | | | - Gérard Lefranc
- CNRS UPR 1142, Montpellier, France
- Université Montpellier 2, Montpellier, France
| | | | - Mireille Claustres
- INSERM U827, Montpellier, France
- Université Montpellier 1, Montpellier, France
- CHRU, Montpellier, France
| | - André Mégarbané
- Unité de Génétique Médicale and Laboratoire Associé INSERM à l’UMR S910, Faculty of Medicine, Saint Joseph University, Beirut, Lebanon
- Institut Jérôme Lejeune, Paris, France
| | - Albertina De Sario
- INSERM U827, Montpellier, France
- Université Montpellier 1, Montpellier, France
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Lacroix J, Halaszovich CR, Schreiber DN, Leitner MG, Bezanilla F, Oliver D, Villalba-Galea CA. Controlling the activity of a phosphatase and tensin homolog (PTEN) by membrane potential. J Biol Chem 2011; 286:17945-53. [PMID: 21454672 DOI: 10.1074/jbc.m110.201749] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The recently discovered voltage-sensitive phosphatases (VSPs) hydrolyze phosphoinositides upon depolarization of the membrane potential, thus representing a novel principle for the transduction of electrical activity into biochemical signals. Here, we demonstrate the possibility to confer voltage sensitivity to cytosolic enzymes. By fusing the tumor suppressor PTEN to the voltage sensor of the prototypic VSP from Ciona intestinalis, Ci-VSP, we generated chimeric proteins that are voltage-sensitive and display PTEN-like enzymatic activity in a strictly depolarization-dependent manner in vivo. Functional coupling of the exogenous enzymatic activity to the voltage sensor is mediated by a phospholipid-binding motif at the interface between voltage sensor and catalytic domains. Our findings reveal that the main domains of VSPs and related phosphoinositide phosphatases are intrinsically modular and define structural requirements for coupling of enzymatic activity to a voltage sensor domain. A key feature of this prototype of novel engineered voltage-sensitive enzymes, termed Ci-VSPTEN, is the novel ability to switch enzymatic activity of PTEN rapidly and reversibly. We demonstrate that experimental control of Ci-VSPTEN can be obtained either by electrophysiological techniques or more general techniques, using potassium-induced depolarization of intact cells. Thus, Ci-VSPTEN provides a novel approach for studying the complex mechanism of activation, cellular control, and pharmacology of this important tumor suppressor. Moreover, by inducing temporally precise perturbation of phosphoinositide concentrations, Ci-VSPTEN will be useful for probing the role and specificity of these messengers in many cellular processes and to analyze the timing of phosphoinositide signaling.
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Affiliation(s)
- Jérôme Lacroix
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, Illinois 60637, USA
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Liang Q, Ding J, Xu R, Xu Z, Zheng S. The novel human endogenous retrovirus-related gene, psiTPTE22-HERV, is silenced by DNA methylation in cancers. Int J Cancer 2010; 127:1833-43. [PMID: 20112338 DOI: 10.1002/ijc.25213] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The psiTPTE22 gene has been designated as a TPTE pseudogene. Our study found that the 5' part of psiTPTE22 has no sequence similarity to TPTE and contains a 3.8-kb human endogenous retrovirus (HERV) element. Because of the HERV element, the 5' part of psiTPTE22 (psiTPTE22-HERV) expresses independently as a gene. Comparison between the DNA sequences of humans and chimps indicated that psiTPTE22-HERV is human specific. We identified 3 alternatively spliced transcript variants from psiTPTE22-HERV by a PCR-based strategy, which use the transcriptional termination signal contained in the HERV element. A 402-nt ORF was contained in the 2 longer transcripts. Western blotting using antibodies produced with chemically synthesized peptide confirmed that a 15-kDa protein was translated from this ORF. RT-PCR results indicated that the ORF-containing transcripts were mainly expressed in psiTPTE22-HERV-expressing samples. Real-time quantitative RT-PCR results showed that expression of the 402-nt ORF was upregulated in normal tissues of kidney, liver, stomach, and lung but downregulated in corresponding tumor tissues. This gene is located near the centromere of chromosome 22 and has a high GC content around the promoter region. Bisulfite sequencing PCR results indicated that it is silenced in cancers by DNA methylation. The expression of psiTPTE22-HERV can be recovered in cancer cells using DNA methylation and histone deacetylase inhibitors. These results suggest psiTPTE22-HERV is regulated epigenetically by DNA methylation. Our study paved the way for further study on an interesting HERV-related human-specific gene, which is silenced in cancers by DNA methylation.
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Affiliation(s)
- Qiaoyi Liang
- Cancer Institute, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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46
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Suppression of cellular proliferation and invasion by the concerted lipid and protein phosphatase activities of PTEN. Oncogene 2009; 29:687-97. [PMID: 19915616 PMCID: PMC2816976 DOI: 10.1038/onc.2009.384] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PTEN is a tumour suppressor with phosphatase activity in vitro against both lipids and proteins and other potential non-enzymatic mechanisms of action. Although the importance of PTEN's lipid phosphatase activity in regulating the PI3K signalling pathway is recognized, the significance of PTEN's other mechanisms of action is currently unclear. In this study, we describe the systematic identification of a PTEN mutant, PTEN Y138L, with activity against lipid, but not soluble substrates. Using this mutant, we provide evidence for the interfacial activation of PTEN against lipid substrates. We also show that when re-expressed at physiological levels in PTEN null U87MG glioblastoma cells, the protein phosphatase activity of PTEN is not required to regulate cellular PtdInsP(3) levels or the downstream protein kinase Akt/PKB. Finally, in three-dimensional Matrigel cultures of U87MG cells similarly re-expressing PTEN mutants, both the protein and lipid phosphatase activities were required to inhibit invasion, but either activity alone significantly inhibited proliferation, albeit only weakly for the protein phosphatase activity. Our data provide a novel tool to address the significance of PTEN's separable lipid and protein phosphatase activities and suggest that both activities suppress proliferation and together suppress invasion.
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Sasaki T, Takasuga S, Sasaki J, Kofuji S, Eguchi S, Yamazaki M, Suzuki A. Mammalian phosphoinositide kinases and phosphatases. Prog Lipid Res 2009; 48:307-43. [PMID: 19580826 DOI: 10.1016/j.plipres.2009.06.001] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phosphoinositides are lipids that are present in the cytoplasmic leaflet of a cell's plasma and internal membranes and play pivotal roles in the regulation of a wide variety of cellular processes. Phosphoinositides are molecularly diverse due to variable phosphorylation of the hydroxyl groups of their inositol rings. The rapid and reversible configuration of the seven known phosphoinositide species is controlled by a battery of phosphoinositide kinases and phosphoinositide phosphatases, which are thus critical for phosphoinositide isomer-specific localization and functions. Significantly, a given phosphoinositide generated by different isozymes of these phosphoinositide kinases and phosphatases can have different biological effects. In mammals, close to 50 genes encode the phosphoinositide kinases and phosphoinositide phosphatases that regulate phosphoinositide metabolism and thus allow cells to respond rapidly and effectively to ever-changing environmental cues. Understanding the distinct and overlapping functions of these phosphoinositide-metabolizing enzymes is important for our knowledge of both normal human physiology and the growing list of human diseases whose etiologies involve these proteins. This review summarizes the structural and biological properties of all the known mammalian phosphoinositide kinases and phosphoinositide phosphatases, as well as their associations with human disorders.
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Affiliation(s)
- Takehiko Sasaki
- Department of Pathology and Immunology, Akita University, Graduate School of Medicine, Akita 010-8543, Japan.
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48
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Suzuki N, Katsusihma H, Takeuchi K, Nakamura S, Ishizawa K, Ishii S, Moriya T, DeCoteau JF, Miura I, Ichinohasama R. Cytogenetic abnormality 46,XX,add(21)(q11.2) in a patient with follicular dendritic cell sarcoma. ACTA ACUST UNITED AC 2008; 186:54-7. [PMID: 18786443 DOI: 10.1016/j.cancergencyto.2008.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 05/27/2008] [Accepted: 06/05/2008] [Indexed: 11/18/2022]
Abstract
The case of a patient with follicular dendritic cell (FDC) sarcoma with chromosomal aberration add(21)(q11.2) is described. Cytogenetic studies showed the karyotype 46,XX,add(21)(q11.2)[3]/46,XX[17], although the encoded protein involved was not clarified. The abnormal pattern was quite simple, and different from a previous report. The clinical course of the FDC sarcoma in this case has been indolent, as for most FDC sarcoma patients. Although this patient suffered from breast carcinoma 6 years after the onset of FDC sarcoma, the carcinoma showed different histological and phenotypic profiles.
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MESH Headings
- Adenocarcinoma, Scirrhous/genetics
- Axilla
- Biomarkers, Tumor/analysis
- Breast Neoplasms/genetics
- Carcinoma, Ductal, Breast/genetics
- Chromosome Aberrations
- Chromosomes, Human, Pair 21
- Dendritic Cell Sarcoma, Follicular/genetics
- Dendritic Cell Sarcoma, Follicular/pathology
- Fatal Outcome
- Female
- Humans
- Immunophenotyping
- Lymph Nodes/pathology
- Middle Aged
- Neoplasm Proteins/analysis
- Neoplasms, Multiple Primary/genetics
- Receptors, Complement 3d/analysis
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Affiliation(s)
- Naomi Suzuki
- Tohoku University School of Medicine, Sendai, Japan
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49
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Gene dosage change of TPTE and BAGE2 and breakpoint analysis in Robertsonian Down syndrome. J Hum Genet 2007; 53:136-143. [DOI: 10.1007/s10038-007-0229-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 11/13/2007] [Indexed: 10/22/2022]
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50
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Lyle R, Prandini P, Osoegawa K, ten Hallers B, Humphray S, Zhu B, Eyras E, Castelo R, Bird CP, Gagos S, Scott C, Cox A, Deutsch S, Ucla C, Cruts M, Dahoun S, She X, Bena F, Wang SY, Van Broeckhoven C, Eichler EE, Guigo R, Rogers J, de Jong PJ, Reymond A, Antonarakis SE. Islands of euchromatin-like sequence and expressed polymorphic sequences within the short arm of human chromosome 21. Genome Res 2007; 17:1690-6. [PMID: 17895424 PMCID: PMC2045151 DOI: 10.1101/gr.6675307] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The goals of the human genome project did not include sequencing of the heterochromatic regions. We describe here an initial sequence of 1.1 Mb of the short arm of human chromosome 21 (HSA21p), estimated to be 10% of 21p. This region contains extensive euchromatic-like sequence and includes on average one transcript every 100 kb. These transcripts show multiple inter- and intrachromosomal copies, and extensive copy number and sequence variability. The sequencing of the "heterochromatic" regions of the human genome is likely to reveal many additional functional elements and provide important evolutionary information.
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Affiliation(s)
- Robert Lyle
- Department of Genetic Medicine and Development, University of Geneva Medical School, and University Hospitals, 1211 Geneva, Switzerland
- Corresponding authors.E-mail ; fax 47-22-11-98-99.E-mail . fax 41-22-379-5706
| | - Paola Prandini
- Department of Genetic Medicine and Development, University of Geneva Medical School, and University Hospitals, 1211 Geneva, Switzerland
| | - Kazutoyo Osoegawa
- Children's Hospital Oakland Research Institute, Oakland, California 94609, USA
| | | | - Sean Humphray
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Baoli Zhu
- Children's Hospital Oakland Research Institute, Oakland, California 94609, USA
| | - Eduardo Eyras
- Research Group on Biomedical Informatics, Pompeu Fabra University and Municipal Insititute of Medical Research, E-8003 Barcelona, Catalonia, Spain
| | - Robert Castelo
- Research Group on Biomedical Informatics, Pompeu Fabra University and Municipal Insititute of Medical Research, E-8003 Barcelona, Catalonia, Spain
| | | | - Sarantos Gagos
- Department of Genetic Medicine and Development, University of Geneva Medical School, and University Hospitals, 1211 Geneva, Switzerland
| | - Carol Scott
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Antony Cox
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Samuel Deutsch
- Department of Genetic Medicine and Development, University of Geneva Medical School, and University Hospitals, 1211 Geneva, Switzerland
| | - Catherine Ucla
- Department of Genetic Medicine and Development, University of Geneva Medical School, and University Hospitals, 1211 Geneva, Switzerland
| | - Marc Cruts
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, University of Antwerp, BE-2610 Antwerpen, Belgium
| | - Sophie Dahoun
- Department of Genetic Medicine and Development, University of Geneva Medical School, and University Hospitals, 1211 Geneva, Switzerland
| | - Xinwei She
- Department of Genome Sciences, University of Washington and Howard Hughes Medical Institute, Seattle, Washington 98195-5065, USA
| | - Frederique Bena
- Department of Genetic Medicine and Development, University of Geneva Medical School, and University Hospitals, 1211 Geneva, Switzerland
| | - Sheng-Yue Wang
- Chinese National Human Genome Center at Shanghai, Shanghai 201203, China
| | - Christine Van Broeckhoven
- Neurodegenerative Brain Diseases Group, Department of Molecular Genetics, VIB, University of Antwerp, BE-2610 Antwerpen, Belgium
| | - Evan E. Eichler
- Department of Genome Sciences, University of Washington and Howard Hughes Medical Institute, Seattle, Washington 98195-5065, USA
| | - Roderic Guigo
- Centre for Genomic Regulation E-8003 Barcelona, Catalonia, Spain
| | - Jane Rogers
- Wellcome Trust Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Pieter J. de Jong
- Children's Hospital Oakland Research Institute, Oakland, California 94609, USA
| | - Alexandre Reymond
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Stylianos E. Antonarakis
- Department of Genetic Medicine and Development, University of Geneva Medical School, and University Hospitals, 1211 Geneva, Switzerland
- Corresponding authors.E-mail ; fax 47-22-11-98-99.E-mail . fax 41-22-379-5706
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