1
|
Suzuki E, Ogawa N, Takeda TA, Nishito Y, Tanaka YK, Fujiwara T, Matsunaga M, Ueda S, Kubo N, Tsuji T, Fukunaka A, Yamazaki T, Taylor KM, Ogra Y, Kambe T. Detailed analyses of the crucial functions of Zn transporter proteins in alkaline phosphatase activation. J Biol Chem 2020; 295:5669-5684. [PMID: 32179649 PMCID: PMC7186172 DOI: 10.1074/jbc.ra120.012610] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/04/2020] [Indexed: 11/06/2022] Open
Abstract
Numerous zinc ectoenzymes are metalated by zinc and activated in the compartments of the early secretory pathway before reaching their destination. Zn transporter (ZNT) proteins located in these compartments are essential for ectoenzyme activation. We have previously reported that ZNT proteins, specifically ZNT5-ZNT6 heterodimers and ZNT7 homodimers, play critical roles in the activation of zinc ectoenzymes, such as alkaline phosphatases (ALPs), by mobilizing cytosolic zinc into these compartments. However, this process remains incompletely understood. Here, using genetically-engineered chicken DT40 cells, we first determined that Zrt/Irt-like protein (ZIP) transporters that are localized to the compartments of the early secretory pathway play only a minor role in the ALP activation process. These transporters included ZIP7, ZIP9, and ZIP13, performing pivotal functions in maintaining cellular homeostasis by effluxing zinc out of the compartments. Next, using purified ALP proteins, we showed that zinc metalation on ALP produced in DT40 cells lacking ZNT5-ZNT6 heterodimers and ZNT7 homodimers is impaired. Finally, by genetically disrupting both ZNT5 and ZNT7 in human HAP1 cells, we directly demonstrated that the tissue-nonspecific ALP-activating functions of both ZNT complexes are conserved in human cells. Furthermore, using mutant HAP1 cells, we uncovered a previously-unrecognized and unique spatial regulation of ZNT5-ZNT6 heterodimer formation, wherein ZNT5 recruits ZNT6 to the Golgi apparatus to form the heterodimeric complex. These findings fill in major gaps in our understanding of the molecular mechanisms underlying zinc ectoenzyme activation in the compartments of the early secretory pathway.
Collapse
Affiliation(s)
- Eisuke Suzuki
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Namino Ogawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Taka-Aki Takeda
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Yukina Nishito
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Yu-Ki Tanaka
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Takashi Fujiwara
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Mayu Matsunaga
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Sachiko Ueda
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Naoya Kubo
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Tokuji Tsuji
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Ayako Fukunaka
- Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan
| | - Tomohiro Yamazaki
- Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan
| | - Kathryn M Taylor
- School of Pharmacy and Pharmaceutical Sciences, Redwood Building, Cardiff University, King Edward VIIth Avenue, Cardiff CF10 3NB, United Kingdom
| | - Yasumitsu Ogra
- Graduate School of Pharmaceutical Sciences, Chiba University, Chiba 260-8675, Japan
| | - Taiho Kambe
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.
| |
Collapse
|
2
|
Liu H. Synaptic organizers: synaptic adhesion-like molecules (SALMs). Curr Opin Struct Biol 2019; 54:59-67. [PMID: 30743183 DOI: 10.1016/j.sbi.2019.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/24/2018] [Accepted: 01/06/2019] [Indexed: 12/18/2022]
Abstract
Synaptic adhesion-like molecules (SALMs), also known as leucine-rich repeat and fibronectin III domain-containing proteins (LRFNs), are a family of synaptic adhesion molecules that consist of five members. SALMs exhibit functions in regulating neurite outgrowth and branching, synapse formation, and synapse maturation. Recent clinical studies have shown an association of SALMs with diverse neurological disorders. In this review article, we summarize structural mechanisms of the interaction of SALMs with leukocyte common antigen (LAR) family receptor tyrosine phosphatases (LAR-RPTPs) for synaptic activity, based on recent advances in the structural biology of SALMs.
Collapse
Affiliation(s)
- Heli Liu
- State Key Laboratory of Natural and Biomimetic Drugs, 38 Xueyuan Road, Haidian District, Beijing 100191, China; Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China.
| |
Collapse
|
3
|
Yu ZH, Zhang ZY. Regulatory Mechanisms and Novel Therapeutic Targeting Strategies for Protein Tyrosine Phosphatases. Chem Rev 2018; 118:1069-1091. [PMID: 28541680 PMCID: PMC5812791 DOI: 10.1021/acs.chemrev.7b00105] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
An appropriate level of protein phosphorylation on tyrosine is essential for cells to react to extracellular stimuli and maintain cellular homeostasis. Faulty operation of signal pathways mediated by protein tyrosine phosphorylation causes numerous human diseases, which presents enormous opportunities for therapeutic intervention. While the importance of protein tyrosine kinases in orchestrating the tyrosine phosphorylation networks and in target-based drug discovery has long been recognized, the significance of protein tyrosine phosphatases (PTPs) in cellular signaling and disease biology has historically been underappreciated, due to a large extent to an erroneous assumption that they are largely constitutive and housekeeping enzymes. Here, we provide a comprehensive examination of a number of regulatory mechanisms, including redox modulation, allosteric regulation, and protein oligomerization, that control PTP activity. These regulatory mechanisms are integral to the myriad PTP-mediated biochemical events and reinforce the concept that PTPs are indispensable and specific modulators of cellular signaling. We also discuss how disruption of these PTP regulatory mechanisms can cause human diseases and how these diverse regulatory mechanisms can be exploited for novel therapeutic development.
Collapse
Affiliation(s)
- Zhi-Hong Yu
- Department of Medicinal Chemistry and Molecular Pharmacology, Department of Chemistry, Center for Cancer Research, and Institute for Drug Discovery, Purdue University, 720 Clinic Drive, West Lafayette, IN 47907
| | - Zhong-Yin Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, Department of Chemistry, Center for Cancer Research, and Institute for Drug Discovery, Purdue University, 720 Clinic Drive, West Lafayette, IN 47907
| |
Collapse
|
4
|
Hendriks W, Bourgonje A, Leenders W, Pulido R. Proteinaceous Regulators and Inhibitors of Protein Tyrosine Phosphatases. Molecules 2018; 23:molecules23020395. [PMID: 29439552 PMCID: PMC6016963 DOI: 10.3390/molecules23020395] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 02/09/2018] [Accepted: 02/09/2018] [Indexed: 12/18/2022] Open
Abstract
Proper control of the phosphotyrosine content in signal transduction proteins is essential for normal cell behavior and is lost in many pathologies. Attempts to normalize aberrant tyrosine phosphorylation levels in disease states currently involve either the application of small compounds that inhibit tyrosine kinases (TKs) or the addition of growth factors or their mimetics to boost receptor-type TK activity. Therapies that target the TK enzymatic counterparts, the multi-enzyme family of protein tyrosine phosphatases (PTPs), are still lacking despite their undisputed involvement in human diseases. Efforts to pharmacologically modulate PTP activity have been frustrated by the conserved structure of the PTP catalytic core, providing a daunting problem with respect to target specificity. Over the years, however, many different protein interaction-based regulatory mechanisms that control PTP activity have been uncovered, providing alternative possibilities to control PTPs individually. Here, we review these regulatory principles, discuss existing biologics and proteinaceous compounds that affect PTP activity, and mention future opportunities to drug PTPs via these regulatory concepts.
Collapse
Affiliation(s)
- Wiljan Hendriks
- Department of Cell Biology, Radboud University Medical Center, Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands.
| | - Annika Bourgonje
- Department of Cell Biology, Radboud University Medical Center, Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands.
| | - William Leenders
- Department of Biochemistry, Radboud University Medical Center, Geert Grooteplein 26, 6525 GA Nijmegen, The Netherlands.
| | - Rafael Pulido
- Biomarkers in Cancer Unit, Biocruces Health Research Institute, 48903 Barakaldo, Spain.
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
| |
Collapse
|
5
|
Structural basis of SALM5-induced PTPδ dimerization for synaptic differentiation. Nat Commun 2018; 9:268. [PMID: 29348579 PMCID: PMC5773555 DOI: 10.1038/s41467-017-02414-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 11/29/2017] [Indexed: 12/29/2022] Open
Abstract
SALM5, a synaptic adhesion molecule implicated in autism, induces presynaptic differentiation through binding to the LAR family receptor protein tyrosine phosphatases (LAR-RPTPs) that have been highlighted as presynaptic hubs for synapse formation. The mechanisms underlying SALM5/LAR-RPTP interaction remain unsolved. Here we report crystal structures of human SALM5 LRR-Ig alone and in complex with human PTPδ Ig1–3 (MeA−). Distinct from other LAR-RPTP ligands, SALM5 mainly exists as a dimer with LRR domains from two protomers packed in an antiparallel fashion. In the 2:2 heterotetrameric SALM5/PTPδ complex, a SALM5 dimer bridges two separate PTPδ molecules. Structure-guided mutations and heterologous synapse formation assays demonstrate that dimerization of SALM5 is prerequisite for its functionality in inducing synaptic differentiation. This study presents a structural template for the SALM family and reveals a mechanism for how a synaptic adhesion molecule directly induces cis-dimerization of LAR-RPTPs into higher-order signaling assembly. Synaptic adhesion molecules mediate synaptic differentiation and formation. Here the authors present the structures of the synaptic adhesion molecule SALM5 alone and in complex with the LAR family receptor protein tyrosine phosphatase (LAR-RPTP) PTPδ, which reveals how SALM5 dimerization facilitates higher-order signaling assembly of LAR-RPTPs.
Collapse
|
6
|
Wu CL, Hardy S, Aubry I, Landry M, Haggarty A, Saragovi HU, Tremblay ML. Identification of function-regulating antibodies targeting the receptor protein tyrosine phosphatase sigma ectodomain. PLoS One 2017; 12:e0178489. [PMID: 28558026 PMCID: PMC5449173 DOI: 10.1371/journal.pone.0178489] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 05/13/2017] [Indexed: 11/18/2022] Open
Abstract
Receptor tyrosine phosphatase sigma (RPTPσ) plays an important role in the regulation of axonal outgrowth and neural regeneration. Recent studies have identified two RPTPσ ligands, chondroitin sulfate proteoglycans (CSPGs) and heparan sulfate proteoglycans (HSPG), which can modulate RPTPσ activity by affecting its dimerization status. Here, we developed a split luciferase assay to monitor RPTPσ dimerization in living cells. Using this system, we demonstrate that heparin, an analog of heparan sulfate, induced the dimerization of RPTPσ, whereas chondroitin sulfate increased RPTPσ activity by inhibiting RPTPσ dimerization. Also, we generated several novel RPTPσ IgG monoclonal antibodies, to identify one that modulates its activity by inducing/stabilizing dimerization in living cells. Lastly, we demonstrate that this antibody promotes neurite outgrowth in SH-SY5Y cells. In summary, we demonstrated that the split luciferase RPTPσ activity assay is a novel high-throughput approach for discovering novel RPTPσ modulators that can promote axonal outgrowth and neural regeneration.
Collapse
Affiliation(s)
- Chia-Lun Wu
- Rosalind and Morris Goodman Cancer Research Centre, Montréal, Canada.,Department of Experimental Medicine, McGill University, Montréal, Canada
| | - Serge Hardy
- Rosalind and Morris Goodman Cancer Research Centre, Montréal, Canada
| | - Isabelle Aubry
- Rosalind and Morris Goodman Cancer Research Centre, Montréal, Canada
| | - Melissa Landry
- Rosalind and Morris Goodman Cancer Research Centre, Montréal, Canada
| | - Allison Haggarty
- Rosalind and Morris Goodman Cancer Research Centre, Montréal, Canada
| | - Horacio Uri Saragovi
- Departments of Oncology, Pharmacology & Therapeutics, McGill University, Montréal, Canada
| | - Michel L Tremblay
- Rosalind and Morris Goodman Cancer Research Centre, Montréal, Canada.,Department of Experimental Medicine, McGill University, Montréal, Canada
| |
Collapse
|
7
|
Rajagopal S, Deb I, Poddar R, Paul S. Aging is associated with dimerization and inactivation of the brain-enriched tyrosine phosphatase STEP. Neurobiol Aging 2016; 41:25-38. [PMID: 27103516 DOI: 10.1016/j.neurobiolaging.2016.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 12/21/2015] [Accepted: 02/04/2016] [Indexed: 10/22/2022]
Abstract
The STriatal-Enriched tyrosine Phosphatase (STEP) is involved in the etiology of several age-associated neurologic disorders linked to oxidative stress and is also known to play a role in neuroprotection by modulating glutamatergic transmission. However, the possible effect of aging on STEP level and activity in the brain is still unclear. In this study, using young (1 month), adult (4 months), and aged (18 months) rats, we show that aging is associated with increase in dimerization and loss of activity of STEP. Increased dimerization of STEP is primarily observed in the cortex and hippocampus and is associated with depletion of both reduced and total glutathione levels, suggesting an increase in oxidative stress. Consistent with this interpretation, studies in cell culture models of glutathione depletion and oxidative stress also demonstrate formation of dimers and higher order oligomers of STEP that involve intermolecular disulfide bond formation between multiple cysteine residues. Conversely, administration of N-acetyl cysteine, a major antioxidant that enhances glutathione biosynthesis, attenuates STEP dimerization both in the cortex and hippocampus. The findings indicate that loss of this intrinsic protective response pathway with age-dependent increase in oxidative stress may be a contributing factor for the susceptibility of the brain to age-associated neurologic disorders.
Collapse
Affiliation(s)
| | - Ishani Deb
- Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Ranjana Poddar
- Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Surojit Paul
- Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA; Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
| |
Collapse
|
8
|
Abstract
Receptor protein tyrosine phosphatases (RPTPs) form a group of over 20 enzymes in vertebrates, each with unique ectodomains subject to potential extracellular interactions with ligands. It has recently become clear that a remarkably diverse range of ligands exist, including homophilic binders, adhesion molecules, neurotrophin receptors, and proteoglycans. Individual RPTPs can bind several ligands, and vice versa, suggesting that complex cell signaling networks exist. The identification of RPTP ligands and where they are located in tissues remains a challenge for a large number of these enzymes. Here we describe some powerful methods that have proved successful for several research groups, leading to our improved understanding of RPTP-ligand interactions and functional regulation.
Collapse
Affiliation(s)
- Andrew William Stoker
- UCL Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK.
| |
Collapse
|
9
|
Ramírez-Tapia AL, Baylón-Pacheco L, Espíritu-Gordillo P, Rosales-Encina JL. Characterization of the protein tyrosine phosphatase PRL from Entamoeba histolytica. Exp Parasitol 2015; 159:168-82. [PMID: 26431820 DOI: 10.1016/j.exppara.2015.09.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 07/13/2015] [Accepted: 09/24/2015] [Indexed: 11/28/2022]
Abstract
Protein tyrosine phosphatase of regenerating liver (PRL) is a group of phosphatases that has not been broadly studied in protozoan parasites. In humans, PRLs are involved in metastatic cancer, the promotion of cell migration and invasion. PTPs have been increasingly recognized as important effectors of host-pathogen interactions. We characterized the only putative protein tyrosine phosphatase PRL (PTP EhPRL) in the eukaryotic human intestinal parasite Entamoeba histolytica. Here, we reported that the EhPRL protein possessed the classical HCX5R catalytic motif of PTPs and the CAAX box characteristic of the PRL family and exhibited 31-32% homology with the three human PRL isoforms. In amebae, the protein was expressed at low but detectable levels. The recombinant protein (rEhPRL) had enzymatic activity with the 3-o-methyl fluorescein phosphate (OMFP) substrate; this enzymatic activity was inhibited by the PTP inhibitor o-vanadate. Using immunofluorescence we showed that native EhPRL was localized to the cytoplasm and plasma membrane. When the trophozoites interacted with collagen, EhPRL relocalized over time to vesicle-like structures. Interaction with fibronectin increased the presence of the enzyme in the cytoplasm. Using RT-PCR, we demonstrated that EhPRL mRNA expression was upregulated when the trophozoites interacted with collagen but not with fibronectin. Trophozoites recovered from amoebic liver abscesses showed higher EhPRL mRNA expression levels than normal trophozoites. These results strongly suggest that EhPRL may play an important role in the biology and adaptive response of the parasite to the host environment during amoebic liver abscess development, thereby participating in the pathogenic mechanism.
Collapse
Affiliation(s)
- Ana Lilia Ramírez-Tapia
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., México D.F., 07360, Mexico
| | - Lidia Baylón-Pacheco
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., México D.F., 07360, Mexico
| | - Patricia Espíritu-Gordillo
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., México D.F., 07360, Mexico
| | - José Luis Rosales-Encina
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del I.P.N., México D.F., 07360, Mexico.
| |
Collapse
|
10
|
Hartin SN, Hudson ML, Yingling C, Ackley BD. A Synthetic Lethal Screen Identifies a Role for Lin-44/Wnt in C. elegans Embryogenesis. PLoS One 2015; 10:e0121397. [PMID: 25938228 PMCID: PMC4418752 DOI: 10.1371/journal.pone.0121397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/31/2015] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The C. elegans proteins PTP-3/LAR-RPTP and SDN-1/Syndecan are conserved cell adhesion molecules. Loss-of-function (LOF) mutations in either ptp-3 or sdn-1 result in low penetrance embryonic developmental defects. Work from other systems has shown that syndecans can function as ligands for LAR receptors in vivo. We used double mutant analysis to test whether ptp-3 and sdn-1 function in a linear genetic pathway during C. elegans embryogenesis. RESULTS We found animals with LOF in both sdn-1 and ptp-3 exhibited a highly penetrant synthetic lethality (SynLet), with only a small percentage of animals surviving to adulthood. Analysis of the survivors demonstrated that these animals had a synergistic increase in the penetrance of embryonic developmental defects. Together, these data strongly suggested PTP-3 and SDN-1 function in parallel during embryogenesis. We subsequently used RNAi to knockdown ~3,600 genes predicted to encode secreted and/or transmembrane molecules to identify genes that interacted with ptp-3 or sdn-1. We found that the Wnt ligand, lin-44, was SynLet with sdn-1, but not ptp-3. We used 4-dimensional time-lapse analysis to characterize the interaction between lin-44 and sdn-1. We found evidence that loss of lin-44 caused defects in the polarization and migration of endodermal precursors during gastrulation, a previously undescribed role for lin-44 that is strongly enhanced by the loss of sdn-1. CONCLUSIONS PTP-3 and SDN-1 function in compensatory pathways during C. elegans embryonic and larval development, as simultaneous loss of both genes has dire consequences for organismal survival. The Wnt ligand lin-44 contributes to the early stages of gastrulation in parallel to sdn-1, but in a genetic pathway with ptp-3. Overall, the SynLet phenotype provides a robust platform to identify ptp-3 and sdn-1 interacting genes, as well as other genes that function in development, yet might be missed in traditional forward genetic screens.
Collapse
Affiliation(s)
- Samantha N. Hartin
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States of America
| | - Martin L. Hudson
- Department of Biology and Physics, Kennesaw State University, Kennesaw, GA, United States of America
| | - Curtis Yingling
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States of America
| | - Brian D. Ackley
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS, United States of America
- * E-mail:
| |
Collapse
|
11
|
Ahuja LG, Gopal B. Bi-domain protein tyrosine phosphatases reveal an evolutionary adaptation to optimize signal transduction. Antioxid Redox Signal 2014; 20:2141-59. [PMID: 24206235 DOI: 10.1089/ars.2013.5721] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
SIGNIFICANCE The bi-domain protein tyrosine phosphatases (PTPs) exemplify functional evolution in signaling proteins for optimal spatiotemporal signal transduction. Bi-domain PTPs are products of gene duplication. The catalytic activity, however, is often localized to one PTP domain. The inactive PTP domain adopts multiple functional roles. These include modulation of catalytic activity, substrate specificity, and stability of the bi-domain enzyme. In some cases, the inactive PTP domain is a receptor for redox stimuli. Since multiple bi-domain PTPs are concurrently active in related cellular pathways, a stringent regulatory mechanism and selective cross-talk is essential to ensure fidelity in signal transduction. RECENT ADVANCES The inactive PTP domain is an activator for the catalytic PTP domain in some cases, whereas it reduces catalytic activity in other bi-domain PTPs. The relative orientation of the two domains provides a conformational rationale for this regulatory mechanism. Recent structural and biochemical data reveal that these PTP domains participate in substrate recruitment. The inactive PTP domain has also been demonstrated to undergo substantial conformational rearrangement and oligomerization under oxidative stress. CRITICAL ISSUES AND FUTURE DIRECTIONS The role of the inactive PTP domain in coupling environmental stimuli with catalytic activity needs to be further examined. Another aspect that merits attention is the role of this domain in substrate recruitment. These aspects have been poorly characterized in vivo. These lacunae currently restrict our understanding of neo-functionalization of the inactive PTP domain in the bi-domain enzyme. It appears likely that more data from these research themes could form the basis for understanding the fidelity in intracellular signal transduction.
Collapse
Affiliation(s)
- Lalima Gagan Ahuja
- 1 Molecular Biophysics Unit, Indian Institute of Science , Bangalore, India
| | | |
Collapse
|
12
|
Yi JH, Katagiri Y, Yu P, Lourie J, Bangayan NJ, Symes AJ, Geller HM. Receptor protein tyrosine phosphatase σ binds to neurons in the adult mouse brain. Exp Neurol 2014; 255:12-8. [PMID: 24530640 DOI: 10.1016/j.expneurol.2014.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/17/2014] [Accepted: 02/07/2014] [Indexed: 01/26/2023]
Abstract
The role of type IIA receptor protein tyrosine phosphatases (RPTPs), which includes LAR, RPTPσ and RPTPδ, in the nervous system is becoming increasingly recognized. Evidence supports a significant role for these RPTPs during the development of the nervous system as well as after injury, and mutations in RPTPs are associated with human disease. However, a major open question is the nature of the ligands that interact with type IIA RPTPs in the adult brain. Candidates include several different proteins as well as the glycosaminoglycan chains of proteoglycans. In order to investigate this problem, we used a receptor affinity probe assay with RPTPσ-AP fusion proteins on sections of adult mouse brain and to cultured neurons. Our results demonstrate that the major binding sites for RPTPσ in adult mouse brain are on neurons and are not proteoglycan GAG chains, as RPTPσ binding overlaps with the neuronal marker NeuN and was not significantly altered by treatments which eliminate chondroitin sulfate, heparan sulfate, or both. We also demonstrate no overlap of binding of RPTPσ with perineuronal nets, and a unique modulation of RPTPσ binding to brain by divalent cations. Our data therefore point to neuronal proteins, rather than CSPGs, as being the ligands for RPTPσ in the adult, uninjured brain.
Collapse
Affiliation(s)
- Jae-Hyuk Yi
- Developmental Neurobiology Section, Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Yasuhiro Katagiri
- Developmental Neurobiology Section, Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Panpan Yu
- Developmental Neurobiology Section, Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jacob Lourie
- Developmental Neurobiology Section, Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nathanael J Bangayan
- Developmental Neurobiology Section, Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Aviva J Symes
- Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA; Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Herbert M Geller
- Developmental Neurobiology Section, Cell Biology and Physiology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
13
|
Muise A, Rotin D. Apical junction complex proteins and ulcerative colitis: a focus on thePTPRSgene. Expert Rev Mol Diagn 2014; 8:465-77. [DOI: 10.1586/14737159.8.4.465] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
14
|
Protein tyrosine phosphatase σ targets apical junction complex proteins in the intestine and regulates epithelial permeability. Proc Natl Acad Sci U S A 2014; 111:693-8. [PMID: 24385580 DOI: 10.1073/pnas.1315017111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Protein tyrosine phosphatase (PTP)σ (PTPRS) was shown previously to be associated with susceptibility to inflammatory bowel disease (IBD). PTPσ(-/-) mice exhibit an IBD-like phenotype in the intestine and show increased susceptibility to acute models of murine colitis. However, the function of PTPσ in the intestine is uncharacterized. Here, we show an intestinal epithelial barrier defect in the PTPσ(-/-) mouse, demonstrated by a decrease in transepithelial resistance and a leaky intestinal epithelium that was determined by in vivo tracer analysis. Increased tyrosine phosphorylation was observed at the plasma membrane of epithelial cells lining the crypts of the small bowel and colon of the PTPσ(-/-) mouse, suggesting the presence of PTPσ substrates in these regions. Using mass spectrometry, we identified several putative PTPσ intestinal substrates that were hyper-tyrosine-phosphorylated in the PTPσ(-/-) mice relative to wild type. Among these were proteins that form or regulate the apical junction complex, including ezrin. We show that ezrin binds to and is dephosphorylated by PTPσ in vitro, suggesting it is a direct PTPσ substrate, and identified ezrin-Y353/Y145 as important sites targeted by PTPσ. Moreover, subcellular localization of the ezrin phosphomimetic Y353E or Y145 mutants were disrupted in colonic Caco-2 cells, similar to ezrin mislocalization in the colon of PTPσ(-/-) mice following induction of colitis. Our results suggest that PTPσ is a positive regulator of intestinal epithelial barrier, which mediates its effects by modulating epithelial cell adhesion through targeting of apical junction complex-associated proteins (including ezrin), a process impaired in IBD.
Collapse
|
15
|
Cordoba SP, Choudhuri K, Zhang H, Bridge M, Basat AB, Dustin ML, van der Merwe PA. The large ectodomains of CD45 and CD148 regulate their segregation from and inhibition of ligated T-cell receptor. Blood 2013; 121:4295-302. [PMID: 23580664 PMCID: PMC3663424 DOI: 10.1182/blood-2012-07-442251] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 03/25/2013] [Indexed: 11/20/2022] Open
Abstract
T-cell receptor (TCR) triggering results in a cascade of intracellular tyrosine phosphorylation events that ultimately leads to T-cell activation. It is dependent on changes in the relative activities of membrane-associated tyrosine kinases and phosphatases near the engaged TCR. CD45 and CD148 are transmembrane tyrosine phosphatases with large ectodomains that have activatory and inhibitory effects on TCR triggering. This study investigates whether and how the ectodomains of CD45 and CD148 modulate their inhibitory effect on TCR signaling. Expression in T cells of forms of these phosphatases with truncated ectodomains inhibited TCR triggering. In contrast, when these phosphatases were expressed with large ectodomains, they had no inhibitory effect. Imaging studies revealed that truncation of the ectodomains enhanced colocalization of these phosphatases with ligated TCR at the immunological synapse. Our results suggest that the large ectodomains of CD45 and CD148 modulate their inhibitory effect by enabling their passive, size-based segregation from ligated TCR, supporting the kinetic-segregation model of TCR triggering.
Collapse
Affiliation(s)
- Shaun-Paul Cordoba
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
16
|
Böhmer F, Szedlacsek S, Tabernero L, Ostman A, den Hertog J. Protein tyrosine phosphatase structure-function relationships in regulation and pathogenesis. FEBS J 2013; 280:413-31. [PMID: 22682070 DOI: 10.1111/j.1742-4658.2012.08655.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Protein phosphorylation on tyrosine residues is tightly controlled by protein tyrosine phosphatases (PTPs) at multiple levels: spatio-temporal expression, subcellular localization and post-translational modification. Structural and functional analysis of the PTP domains has provided insight into catalysis and regulatory mechanisms that control the enzymatic activity. Understanding the molecular basis of PTP regulation is of fundamental importance to dissect the pleiotropic effect of these enzymes in both health and disease. Here, we review recent insights into the regulation of receptor-like PTPs by extracellular ligands and into regulation by reversible oxidation that impairs catalysis directly. The physiological roles of PTPs are essential in homeostasis in eukaryotic cells and pertubation of their functional attributes causes different disease states. As an example, we discuss recent findings indicating how inappropriate oxidation of PTPs in cancer cells may contribute to cell transformation. On the other hand, PTPs from many pathogens are key virulence factors and manipulate signalling pathways in the host cells to promote invasion and survival of the microorganisms. This research area has received relatively little attention but has advanced remarkably. We review the structural features of pathogenic PTPs, their similarities and differences with eukaryotic PTPs, and the possible exploitation of this knowledge for therapeutic intervention.
Collapse
Affiliation(s)
- Frank Böhmer
- Center for Molecular Biomedicine, Jena University Hospital, Jena, Germany
| | | | | | | | | |
Collapse
|
17
|
Chien PN, Ryu SE. Protein Tyrosine Phosphatase σ in Proteoglycan-Mediated Neural Regeneration Regulation. Mol Neurobiol 2012; 47:220-7. [DOI: 10.1007/s12035-012-8346-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 08/27/2012] [Indexed: 12/25/2022]
|
18
|
Mohebiany AN, Nikolaienko RM, Bouyain S, Harroch S. Receptor-type tyrosine phosphatase ligands: looking for the needle in the haystack. FEBS J 2012; 280:388-400. [PMID: 22682003 DOI: 10.1111/j.1742-4658.2012.08653.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Reversible protein phosphorylation plays a pivotal role in intercellular communication. Together with protein tyrosine kinases, protein tyrosine phosphatases (PTPs) are involved in the regulation of key cellular processes by controlling the phosphorylation levels of diverse effectors. Among PTPs, receptor-like protein tyrosine phosphatases (RPTPs) are involved in important developmental processes, particularly in the formation of the nervous system. Until recently, few ligands had been identified for RPTPs, making it difficult to grasp the effects these receptors have on cellular processes, as well as the mechanisms through which their functions are mediated. However, several potential RPTP ligands have now been identified to provide us with unparalleled insights into RPTP function. In this review, we focus on the nature and biological outcomes of these extracellular interactions between RPTPs and their associated ligands.
Collapse
Affiliation(s)
- Alma N Mohebiany
- Department of Neuroscience, Institut Pasteur de Paris, Paris, France
| | | | | | | |
Collapse
|
19
|
Hou L, Wang J, Zhou Y, Li J, Zang Y, Li J. Structural insights into the homology and differences between mouse protein tyrosine phosphatase-sigma and human protein tyrosine phosphatase-sigma. Acta Biochim Biophys Sin (Shanghai) 2011; 43:977-88. [PMID: 22027896 DOI: 10.1093/abbs/gmr095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Protein tyrosine phosphatases PTP-sigma (PTPσ) plays an important role in the development of the nervous system and nerve regeneration. Although cumulative studies about the function of PTPσ have been reported, yet limited data have been reported about the crystal structure and in vitro activity of mouse PTPσ. Here we report the crystal structure of mouse PTPσ tandem phosphatase domains at 2.4 Å resolution. Then we compared the crystal structure of mouse PTPσ with human PTPσ and found that they are very similar, superimposing with a root mean square deviation of 0.45 Å for 517 equivalent Cα atoms. But some residues in mouse PTPσ form loops while corresponding residues in human PTPσ form β-sheets or α-helices. Furthermore, we also compared in vitro activities of mouse PTPσ with human PTPσ and found that mouse PTPσ has 25-fold higher specific activity than human PTPσ does toward O-methyl fluorescein phosphate (OMFP) as the substrate. However, there is no significant activity difference between the mouse and the human enzyme detected with p-nitrophenylphosphate (pNPP) as the substrate. Mouse PTPσ and human PTPσ have different substrate specificities toward OMFP and pNPP as substrates. This work gives clues for further study of PTPσ.
Collapse
Affiliation(s)
- Li Hou
- School of Life Science, East China Normal University, Shanghai, China
| | | | | | | | | | | |
Collapse
|
20
|
Dukhande VV, Rogers DM, Romá-Mateo C, Donderis J, Marina A, Taylor AO, Sanz P, Gentry MS. Laforin, a dual specificity phosphatase involved in Lafora disease, is present mainly as monomeric form with full phosphatase activity. PLoS One 2011; 6:e24040. [PMID: 21887368 PMCID: PMC3162602 DOI: 10.1371/journal.pone.0024040] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 08/02/2011] [Indexed: 11/18/2022] Open
Abstract
Lafora Disease (LD) is a fatal neurodegenerative epileptic disorder that presents as a neurological deterioration with the accumulation of insoluble, intracellular, hyperphosphorylated carbohydrates called Lafora bodies (LBs). LD is caused by mutations in either the gene encoding laforin or malin. Laforin contains a dual specificity phosphatase domain and a carbohydrate-binding module, and is a member of the recently described family of glucan phosphatases. In the current study, we investigated the functional and physiological relevance of laforin dimerization. We purified recombinant human laforin and subjected the monomer and dimer fractions to denaturing gel electrophoresis, mass spectrometry, phosphatase assays, protein-protein interaction assays, and glucan binding assays. Our results demonstrate that laforin prevalently exists as a monomer with a small dimer fraction both in vitro and in vivo. Of mechanistic importance, laforin monomer and dimer possess equal phosphatase activity, and they both associate with malin and bind glucans to a similar extent. However, we found differences between the two states' ability to interact simultaneously with malin and carbohydrates. Furthermore, we tested other members of the glucan phosphatase family. Cumulatively, our data suggest that laforin monomer is the dominant form of the protein and that it contains phosphatase activity.
Collapse
Affiliation(s)
- Vikas V. Dukhande
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States of America
| | - Devin M. Rogers
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States of America
| | - Carlos Romá-Mateo
- Instituto de Biomedicina de Valencia, CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Jordi Donderis
- Instituto de Biomedicina de Valencia, CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Alberto Marina
- Instituto de Biomedicina de Valencia, CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
| | - Adam O. Taylor
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States of America
| | - Pascual Sanz
- Instituto de Biomedicina de Valencia, CSIC and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Valencia, Spain
- * E-mail: (PS); (MG)
| | - Matthew S. Gentry
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, College of Medicine, University of Kentucky, Lexington, Kentucky, United States of America
- * E-mail: (PS); (MG)
| |
Collapse
|
21
|
Ostman A, Frijhoff J, Sandin A, Böhmer FD. Regulation of protein tyrosine phosphatases by reversible oxidation. J Biochem 2011; 150:345-56. [PMID: 21856739 DOI: 10.1093/jb/mvr104] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Oxidation of the catalytic cysteine of protein-tyrosine phosphatases (PTP), which leads to their reversible inactivation, has emerged as an important regulatory mechanism linking cellular tyrosine phosphorylation and signalling by reactive-oxygen or -nitrogen species (ROS, RNS). This review focuses on recent findings about the involved pathways, enzymes and biochemical mechanisms. Both the general cellular redox state and extracellular ligand-stimulated ROS production can cause PTP oxidation. Members of the PTP family differ in their intrinsic susceptibility to oxidation, and different types of oxidative modification of the PTP catalytic cysteine can occur. The role of PTP oxidation for physiological signalling processes as well as in different pathologies is described on the basis of well-investigated examples. Criteria to establish the causal involvement of PTP oxidation in a given process are proposed. A better understanding of mechanisms leading to selective PTP oxidation in a cellular context, and finding ways to pharmacologically modulate these pathways are important topics for future research.
Collapse
Affiliation(s)
- Arne Ostman
- Cancer Center Karolinska, Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden.
| | | | | | | |
Collapse
|
22
|
Chesini IM, Debyser G, Croes H, Ten Dam GB, Devreese B, Stoker AW, Hendriks WJAJ. PTPBR7 binding proteins in myelinating neurons of the mouse brain. Int J Biol Sci 2011; 7:978-91. [PMID: 21850207 PMCID: PMC3157272 DOI: 10.7150/ijbs.7.978] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 07/21/2011] [Indexed: 12/29/2022] Open
Abstract
Mouse protein tyrosine phosphatase PTPBR7 is a receptor-like, transmembrane protein that is localized on the surface of neuronal cells. Its protein phosphatase activity is reduced upon multimerization, and PTPBR7-deficient mice display motor coordination defects. Extracellular molecules that may influence PTPBR7 activity, however, remain to be determined. We here show that the PTPBR7 extracellular domain binds to highly myelinated regions in mouse brain, in particular the white matter tracks in cerebellum. PTPBR7 deficiency does not alter this binding pattern, as witnessed by RAP in situ staining of Ptprr-/- mouse brain sections. Additional in situ and in vitro experiments also suggest that sugar moieties of heparan sulphate and chondroitin sulphate glycosaminoglycans are not critical for PTPBR7 binding. Candidate binding proteins were affinity-purified exploiting the PTPBR7 extracellular domain and identified by mass spectrometric means. Results support the suggested link between PTPRR isoforms and cerebellar calcium ion homeostasis, and suggest an additional role in the process of cell-cell adhesion.
Collapse
Affiliation(s)
- Irene M Chesini
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
23
|
Deb I, Poddar R, Paul S. Oxidative stress-induced oligomerization inhibits the activity of the non-receptor tyrosine phosphatase STEP61. J Neurochem 2011; 116:1097-111. [PMID: 21198639 DOI: 10.1111/j.1471-4159.2010.07165.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The neuron-specific tyrosine phosphatase STriatal Enriched Phosphatase (STEP) is emerging as an important mediator of glutamatergic transmission in the brain. STEP is also thought to be involved in the etiology of neurodegenerative disorders that are linked to oxidative stress such as Alzheimer's disease and cerebral ischemia. However, the mechanism by which oxidative stress can modulate STEP activity is still unclear. In this study, we have investigated whether dimerization may play a role in regulating the activity of STEP. Our findings show that STEP(61), the membrane associated isoform, can undergo homodimerization under basal conditions in neurons. Dimerization of STEP(61) involves intermolecular disulfide bond formation between two cysteine residues (Cys 65 and Cys 76 respectively) present in the hydrophobic region at the N-terminus specific to STEP(61). Oxidative stress induced by hydrogen peroxide leads to a significant increase in the formation of dimers and higher-order oligomers of STEP(61). Using two substrates, para-nitrophenylphosphate and extracellular-regulated kinase MAPK we further demonstrate that oligomerization leads to a significant reduction in its enzymatic activity.
Collapse
Affiliation(s)
- Ishani Deb
- Department of Neurology, University of New Mexico Health Sciences Center, 1 University of New Mexico, Albuquerque, New Mexico 87131, USA
| | | | | |
Collapse
|
24
|
Heikkinen J, Risteli M, Lampela O, Alavesa P, Karppinen M, Juffer AH, Myllylä R. Dimerization of human lysyl hydroxylase 3 (LH3) is mediated by the amino acids 541–547. Matrix Biol 2011; 30:27-33. [DOI: 10.1016/j.matbio.2010.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 10/08/2010] [Accepted: 10/08/2010] [Indexed: 11/16/2022]
|
25
|
The receptor protein tyrosine phosphatase LAR promotes R7 photoreceptor axon targeting by a phosphatase-independent signaling mechanism. Proc Natl Acad Sci U S A 2009; 106:19399-404. [PMID: 19889974 DOI: 10.1073/pnas.0903961106] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Receptor protein tyrosine phosphatases (RPTPs) control many aspects of nervous system development. At the Drosophila neuromuscular junction (NMJ), regulation of synapse growth and maturation by the RPTP LAR depends on catalytic phosphatase activity and on the extracellular ligands Syndecan and Dally-like. We show here that the function of LAR in controlling R7 photoreceptor axon targeting in the visual system differs in several respects. The extracellular domain of LAR important for this process is distinct from the domains known to bind Syndecan and Dally-like, suggesting the involvement of a different ligand. R7 targeting does not require LAR phosphatase activity, but instead depends on the phosphatase activity of another RPTP, PTP69D. In addition, a mutation that prevents dimerization of the intracellular domain of LAR interferes with its ability to promote R7 targeting, although it does not disrupt phosphatase activity or neuromuscular synapse growth. We propose that LAR function in R7 is independent of its phosphatase activity, but requires structural features that allow dimerization and may promote the assembly of downstream effectors.
Collapse
|
26
|
Hower AE, Beltran PJ, Bixby JL. Dimerization of tyrosine phosphatase PTPRO decreases its activity and ability to inactivate TrkC. J Neurochem 2009; 110:1635-47. [PMID: 19573017 DOI: 10.1111/j.1471-4159.2009.06261.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Receptor-protein tyrosine phosphatases (RPTPs), like receptor tyrosine kinases, regulate neuronal differentiation. While receptor tyrosine kinases are dimerized and activated by extracellular ligands, the extent to which RPTPs dimerize, and the effects of dimerization on phosphatase activity, are poorly understood. We have examined a neuronal type III RPTP, PTPRO; we find that PTPRO can form dimers in living cells, and that disulfide linkages in PTPROs intracellular domain likely regulate dimerization. Dimerization of PTPROs transmembrane and intracellular domains, achieved by ligand binding to a chimeric fusion protein, decreases activity toward artificial peptides and toward a putative substrate, tropomyosin-related kinase C (TrkC). Dephosphorylation of TrkC by PTPRO may be physiologically relevant, as it is efficient, and TrkC and PTPRO can be co-precipitated from transfected cells. Inhibition of PTPROs phosphatase activity by dimerization is interesting, as dimerization of a related RPTP, CD148/PTPRJ, increases activity. Thus, our results suggest a complex relationship between dimerization and activity in type III RPTPs.
Collapse
|
27
|
Barr AJ, Ugochukwu E, Lee WH, King ON, Filippakopoulos P, Alfano I, Savitsky P, Burgess-Brown NA, Müller S, Knapp S. Large-scale structural analysis of the classical human protein tyrosine phosphatome. Cell 2009; 136:352-63. [PMID: 19167335 PMCID: PMC2638020 DOI: 10.1016/j.cell.2008.11.038] [Citation(s) in RCA: 358] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 09/15/2008] [Accepted: 11/20/2008] [Indexed: 02/05/2023]
Abstract
Protein tyrosine phosphatases (PTPs) play a critical role in regulating cellular functions by selectively dephosphorylating their substrates. Here we present 22 human PTP crystal structures that, together with prior structural knowledge, enable a comprehensive analysis of the classical PTP family. Despite their largely conserved fold, surface properties of PTPs are strikingly diverse. A potential secondary substrate-binding pocket is frequently found in phosphatases, and this has implications for both substrate recognition and development of selective inhibitors. Structural comparison identified four diverse catalytic loop (WPD) conformations and suggested a mechanism for loop closure. Enzymatic assays revealed vast differences in PTP catalytic activity and identified PTPD1, PTPD2, and HDPTP as catalytically inert protein phosphatases. We propose a “head-to-toe” dimerization model for RPTPγ/ζ that is distinct from the “inhibitory wedge” model and that provides a molecular basis for inhibitory regulation. This phosphatome resource gives an expanded insight into intrafamily PTP diversity, catalytic activity, substrate recognition, and autoregulatory self-association.
Collapse
Affiliation(s)
- Alastair J. Barr
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
- Corresponding author
| | - Emilie Ugochukwu
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Wen Hwa Lee
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Oliver N.F. King
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Panagis Filippakopoulos
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Ivan Alfano
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Pavel Savitsky
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Nicola A. Burgess-Brown
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Susanne Müller
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
| | - Stefan Knapp
- University of Oxford, Structural Genomics Consortium, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford, OX3 7DQ, UK
- University of Oxford, Department of Clinical Pharmacology, Old Road Campus, Roosevelt Drive, Oxford OX3 7DQ, UK
- Corresponding author
| |
Collapse
|
28
|
Groen A, Overvoorde J, van der Wijk T, den Hertog J. Redox regulation of dimerization of the receptor protein-tyrosine phosphatases RPTPα, LAR, RPTPμ and CD45. FEBS J 2008; 275:2597-604. [DOI: 10.1111/j.1742-4658.2008.06407.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
29
|
Abstract
Protein-tyrosine phosphatases are tightly controlled by various mechanisms, ranging from differential expression in specific cell types to restricted subcellular localization, limited proteolysis, post-translational modifications affecting intrinsic catalytic activity, ligand binding and dimerization. Here, we review the regulatory mechanisms found to control the classical protein-tyrosine phosphatases.
Collapse
|
30
|
Granot-Attas S, Elson A. Protein tyrosine phosphatases in osteoclast differentiation, adhesion, and bone resorption. Eur J Cell Biol 2008; 87:479-90. [PMID: 18342392 DOI: 10.1016/j.ejcb.2008.01.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2007] [Revised: 01/16/2008] [Accepted: 01/16/2008] [Indexed: 01/06/2023] Open
Abstract
Osteoclasts are large cells derived from the monocyte-macrophage hematopoietic cell lineage. Their primary function is to degrade bone in various physiological contexts. Osteoclasts adhere to bone via podosomes, specialized adhesion structures whose structure and subcellular organization are affected by mechanical contact of the cell with bone matrix. Ample evidence indicates that reversible tyrosine phosphorylation of podosomal proteins plays a major role in determining the organization and dynamics of podosomes. Although roles of several tyrosine kinases are known in detail in this respect, little is known concerning the roles of protein tyrosine phosphatases (PTPs) in regulating osteoclast adhesion. Here we summarize available information concerning the known and hypothesized roles of the best-researched PTPs in osteoclasts - PTPRO, PTP epsilon, SHP-1, and PTP-PEST. Of these, PTPRO, PTP epsilon, and PTP-PEST appear to support osteoclast activity while SHP-1 inhibits it. Additional studies are required to provide full molecular details of the roles of these PTPs in regulating osteoclast adhesion, and to uncover additional PTPs that participate in this process.
Collapse
Affiliation(s)
- Shira Granot-Attas
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | | |
Collapse
|
31
|
Hendriks WJAJ, Elson A, Harroch S, Stoker AW. Protein tyrosine phosphatases: functional inferences from mouse models and human diseases. FEBS J 2008; 275:816-30. [DOI: 10.1111/j.1742-4658.2008.06249.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
32
|
Almo SC, Bonanno JB, Sauder JM, Emtage S, Dilorenzo TP, Malashkevich V, Wasserman SR, Swaminathan S, Eswaramoorthy S, Agarwal R, Kumaran D, Madegowda M, Ragumani S, Patskovsky Y, Alvarado J, Ramagopal UA, Faber-Barata J, Chance MR, Sali A, Fiser A, Zhang ZY, Lawrence DS, Burley SK. Structural genomics of protein phosphatases. ACTA ACUST UNITED AC 2007; 8:121-40. [PMID: 18058037 DOI: 10.1007/s10969-007-9036-1] [Citation(s) in RCA: 136] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 11/06/2007] [Indexed: 12/11/2022]
Abstract
The New York SGX Research Center for Structural Genomics (NYSGXRC) of the NIGMS Protein Structure Initiative (PSI) has applied its high-throughput X-ray crystallographic structure determination platform to systematic studies of all human protein phosphatases and protein phosphatases from biomedically-relevant pathogens. To date, the NYSGXRC has determined structures of 21 distinct protein phosphatases: 14 from human, 2 from mouse, 2 from the pathogen Toxoplasma gondii, 1 from Trypanosoma brucei, the parasite responsible for African sleeping sickness, and 2 from the principal mosquito vector of malaria in Africa, Anopheles gambiae. These structures provide insights into both normal and pathophysiologic processes, including transcriptional regulation, regulation of major signaling pathways, neural development, and type 1 diabetes. In conjunction with the contributions of other international structural genomics consortia, these efforts promise to provide an unprecedented database and materials repository for structure-guided experimental and computational discovery of inhibitors for all classes of protein phosphatases.
Collapse
Affiliation(s)
- Steven C Almo
- Albert Einstein College of Medicine, Bronx, NY, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Faux C, Hawadle M, Nixon J, Wallace A, Lee S, Murray S, Stoker A. PTPσ binds and dephosphorylates neurotrophin receptors and can suppress NGF-dependent neurite outgrowth from sensory neurons. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:1689-700. [DOI: 10.1016/j.bbamcr.2007.06.008] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2007] [Revised: 06/22/2007] [Accepted: 06/25/2007] [Indexed: 12/25/2022]
|