1
|
Poirier A, Picard C, Labonté A, Aubry I, Auld D, Zetterberg H, Blennow K, Tremblay ML, Poirier J. PTPRS is a novel marker for early Tau pathology and synaptic integrity in Alzheimer's disease. Sci Rep 2024; 14:14718. [PMID: 38926456 PMCID: PMC11208446 DOI: 10.1038/s41598-024-65104-2] [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: 03/21/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
We examined the role of protein tyrosine phosphatase receptor sigma (PTPRS) in the context of Alzheimer's disease and synaptic integrity. Publicly available datasets (BRAINEAC, ROSMAP, ADC1) and a cohort of asymptomatic but "at risk" individuals (PREVENT-AD) were used to explore the relationship between PTPRS and various Alzheimer's disease biomarkers. We identified that PTPRS rs10415488 variant C shows features of neuroprotection against early Tau pathology and synaptic degeneration in Alzheimer's disease. This single nucleotide polymorphism correlated with higher PTPRS transcript abundance and lower p(181)Tau and GAP-43 levels in the CSF. In the brain, PTPRS protein abundance was significantly correlated with the quantity of two markers of synaptic integrity: SNAP25 and SYT-1. We also found the presence of sexual dimorphism for PTPRS, with higher CSF concentrations in males than females. Male carriers for variant C were found to have a 10-month delay in the onset of AD. We thus conclude that PTPRS acts as a neuroprotective receptor in Alzheimer's disease. Its protective effect is most important in males, in whom it postpones the age of onset of the disease.
Collapse
Affiliation(s)
- Alexandre Poirier
- Division of Experimental Medicine, Faculty of Medicine and Health Science, McGill University, Montréal, QC, Canada
- Goodman Cancer Institute, McGill University, Montréal, Canada
| | - Cynthia Picard
- Douglas Mental Health University Institute, Montréal, QC, Canada
- Centre for the Studies in the Prevention of Alzheimer's Disease, Montréal, QC, Canada
| | - Anne Labonté
- Douglas Mental Health University Institute, Montréal, QC, Canada
- Centre for the Studies in the Prevention of Alzheimer's Disease, Montréal, QC, Canada
| | - Isabelle Aubry
- Goodman Cancer Institute, McGill University, Montréal, Canada
- McGill University, Montréal, QC, Canada
| | - Daniel Auld
- McGill University, Montréal, QC, Canada
- Victor Phillip Dahdaleh Institute of Genomic Medicine, McGill University, Montréal, QC, Canada
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK
- UK Dementia Research Institute at UCL, London, UK
- Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, SAR, People's Republic of China
- Wisconsin Alzheimer's Disease Research Center, University of Wisconsin School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
- University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK
- University of Science and Technology of China, Hefei, Anhui, People's Republic of China
- Institut du Cerveau et de la Moelle épinière (ICM), Pitié-Salpêtrière Hospital, Sorbonne Université, Paris, France
| | - Michel L Tremblay
- Division of Experimental Medicine, Faculty of Medicine and Health Science, McGill University, Montréal, QC, Canada.
- Goodman Cancer Institute, McGill University, Montréal, Canada.
- McGill University, Montréal, QC, Canada.
- Department of Biochemistry, McGill University, Montréal, Canada.
| | - Judes Poirier
- Douglas Mental Health University Institute, Montréal, QC, Canada.
- Centre for the Studies in the Prevention of Alzheimer's Disease, Montréal, QC, Canada.
- McGill University, Montréal, QC, Canada.
| |
Collapse
|
2
|
Poirier A, Picard C, Labonté A, Aubry I, Auld D, Zetterberg H, Blennow K, Tremblay ML, Poirier J. PTPRS is a novel marker for early tau pathology and synaptic integrity in Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.12.593733. [PMID: 38766183 PMCID: PMC11100782 DOI: 10.1101/2024.05.12.593733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
We examined the role of protein tyrosine phosphatase receptor sigma (PTPRS) in the context of Alzheimer's disease and synaptic integrity. Publicly available datasets (BRAINEAC, ROSMAP, ADC1) and a cohort of asymptomatic but "at risk" individuals (PREVENT-AD) were used to explore the relationship between PTPRS and various Alzheimer's disease biomarkers. We identified that PTPRS rs10415488 variant C shows features of neuroprotection against early tau pathology and synaptic degeneration in Alzheimer's disease. This single nucleotide polymorphism correlated with higher PTPRS transcript abundance and lower P-tau181 and GAP-43 levels in the CSF. In the brain, PTPRS protein abundance was significantly correlated with the quantity of two markers of synaptic integrity: SNAP25 and SYT-1. We also found the presence of sexual dimorphism for PTPRS, with higher CSF concentrations in males than females. Male carriers for variant C were found to have a 10-month delay in the onset of AD. We thus conclude that PTPRS acts as a neuroprotective receptor in Alzheimer's disease. Its protective effect is most important in males, in whom it postpones the age of onset of the disease.
Collapse
|
3
|
Xie X, Luo L, Liang M, Zhang W, Zhang T, Yu C, Wei Z. Structural basis of liprin-α-promoted LAR-RPTP clustering for modulation of phosphatase activity. Nat Commun 2020; 11:169. [PMID: 31924785 PMCID: PMC6954185 DOI: 10.1038/s41467-019-13949-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/10/2019] [Indexed: 02/08/2023] Open
Abstract
Leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs) are cell adhesion molecules involved in mediating neuronal development. The binding of LAR-RPTPs to extracellular ligands induces local clustering of LAR-RPTPs to regulate axon growth and synaptogenesis. LAR-RPTPs interact with synaptic liprin-α proteins via the two cytoplasmic phosphatase domains, D1 and D2. Here we solve the crystal structure of LAR_D1D2 in complex with the SAM repeats of liprin-α3, uncovering a conserved two-site binding mode. Cellular analysis shows that liprin-αs robustly promote clustering of LAR in cells by both the liprin-α/LAR interaction and the oligomerization of liprin-α. Structural analysis reveals a unique homophilic interaction of LAR via the catalytically active D1 domains. Disruption of the D1/D1 interaction diminishes the liprin-α-promoted LAR clustering and increases tyrosine dephosphorylation, demonstrating that the phosphatase activity of LAR is negatively regulated by forming clusters. Additionally, we find that the binding of LAR to liprin-α allosterically regulates the liprin-α/liprin-β interaction. Leukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs) mediate guided axon growth and synapse formation and liprin-α proteins are their intracellular binding partners. Here the authors present the crystal structure of the phosphatase domains from the LAR-RPTP family member LAR bound to the SAM repeats of liprin-α3 and show that liprin-α binding enhances LAR cluster formation and reduces LAR phosphatase activity in cells.
Collapse
Affiliation(s)
- Xingqiao Xie
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.,Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Ling Luo
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Mingfu Liang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Wenchao Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Ting Zhang
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.,Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China
| | - Cong Yu
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.,Guangdong Provincial Key Laboratory of Cell Microenvironment and Disease Research, and Shenzhen Key Laboratory of Cell Microenvironment, Shenzhen, Guangdong, 518055, China
| | - Zhiyi Wei
- Department of Biology, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China. .,Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
| |
Collapse
|
4
|
Ma YC, Yang B, Wang X, Zhou L, Li WY, Liu WS, Lu XH, Zheng ZH, Ma Y, Wang RL. Identification of novel inhibitor of protein tyrosine phosphatases delta: structure-based pharmacophore modeling, virtual screening, flexible docking, molecular dynamics simulation, and post-molecular dynamics analysis. J Biomol Struct Dyn 2019; 38:4432-4448. [PMID: 31625456 DOI: 10.1080/07391102.2019.1682050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Owing to their unique functions in regulating the synapse activity of protein tyrosine phosphatases delta (PTPδ) that has drawn special attention for developing drugs to autism spectrum disorders (ASDs). In this study, the PTPδ pharmacophore was first established by the structure-based pharmacophore method. Subsequently, 10 compounds contented Lipinski's rule of five was acquired by the virtual screening of the PTPδ pharmacophore against ZINC and PubChem databases. Then, the 10 identified molecules were discovered that had better binding affinity than a known PTPδ inhibitors compound SCHEMBL16375396. Two compounds SCHEMBL16375408 and ZINC19796658 with high binding score, low toxicity were gained. They were observed by docking analysis and molecular dynamics simulations that the novel potential inhibitors not only possessed the same function as SCHEMBL16375396 did in inhibiting PTPδ, but also had more favorable conformation to bind with the catalytic active regions. This study provides a new method for identify PTPδ inhibitor for the treatment of ASDs disease.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Yang-Chun Ma
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Bing Yang
- Department of Cell Biology, School of Basic Medical Science, Tianjin Medical University, Tianjin, China
| | - Xin Wang
- Tasly Pharmaceutical Group Co., Ltd., Tianjin, China
| | - Liang Zhou
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Wei-Ya Li
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Wen-Shan Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Xin-Hua Lu
- New Drug Research and Development Center of North China Pharmaceutical Group Corporation, National Microbial Medicine Engineering and Research Center, Hebei Industry Microbial Metabolic Engineering & Technology Research Center, Key Laboratory for New Drug Screening Technology of Shijiazhuang City, Shijiazhuang, Hebei, China
| | - Zhi-Hui Zheng
- New Drug Research and Development Center of North China Pharmaceutical Group Corporation, National Microbial Medicine Engineering and Research Center, Hebei Industry Microbial Metabolic Engineering & Technology Research Center, Key Laboratory for New Drug Screening Technology of Shijiazhuang City, Shijiazhuang, Hebei, China
| | - Ying Ma
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| | - Run-Ling Wang
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin, China
| |
Collapse
|
5
|
Wang X, Liu D, Huang HZ, Wang ZH, Hou TY, Yang X, Pang P, Wei N, Zhou YF, Dupras MJ, Calon F, Wang YT, Man HY, Chen JG, Wang JZ, Hébert SS, Lu Y, Zhu LQ. A Novel MicroRNA-124/PTPN1 Signal Pathway Mediates Synaptic and Memory Deficits in Alzheimer's Disease. Biol Psychiatry 2018; 83:395-405. [PMID: 28965984 DOI: 10.1016/j.biopsych.2017.07.023] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 06/30/2017] [Accepted: 07/01/2017] [Indexed: 12/17/2022]
Abstract
BACKGROUND Synaptic loss is an early pathological event in Alzheimer's disease (AD), but its underlying molecular mechanisms remain largely unknown. Recently, microRNAs (miRNAs) have emerged as important modulators of synaptic function and memory. METHODS We used miRNA array and quantitative polymerase chain reaction to examine the alteration of miRNAs in AD mice and patients as well as the Morris water maze to evaluate learning and memory in the mice. We also used adeno-associated virus or lentivirus to introduce tyrosine-protein phosphatase non-receptor type 1 (PTPN1) expression of silencing RNAs. Long-term potentiation and Golgi staining were used to evaluate the synaptic function and structure. We designed a peptide to interrupt miR-124/PTPN1 interaction. RESULTS Here we report that neuronal miR-124 is dramatically increased in the hippocampus of Tg2576 mice, a recognized AD mouse model. Similar changes were observed in specific brain regions of affected AD individuals. We further identified PTPN1 as a direct target of miR-124. Overexpression of miR-124 or knockdown of PTPN1 recapitulated AD-like phenotypes in mice, including deficits in synaptic transmission and plasticity as well as memory by impairing the glutamate receptor 2 membrane insertion. Most importantly, rebuilding the miR-124/PTPN1 pathway by suppression of miR-124, overexpression of PTPN1, or application of a peptide that disrupts the miR-124/PTPN1 interaction could restore synaptic failure and memory deficits. CONCLUSIONS Taken together, these results identified the miR-124/PTPN1 pathway as a critical mediator of synaptic dysfunction and memory loss in AD, and the miR-124/PTPN1 pathway could be considered as a promising novel therapeutic target for AD patients.
Collapse
Affiliation(s)
- Xiong Wang
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Dan Liu
- Department of Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - He-Zhou Huang
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Zhi-Hao Wang
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Tong-Yao Hou
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Xin Yang
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Pei Pang
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Na Wei
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Ya-Fan Zhou
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Marie-Josée Dupras
- Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Department of Psychiatry and Neuroscience, Université Laval, Québec City, Québec, Canada
| | - Frédéric Calon
- Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Department of Psychiatry and Neuroscience, Université Laval, Québec City, Québec, Canada
| | - Yu-Tian Wang
- Brain Research Centre and Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Heng-Ye Man
- Department of Biology, Boston University, Boston, Massachusetts
| | - Jian-Guo Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Jian-Zhi Wang
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Sébastien S Hébert
- Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Department of Psychiatry and Neuroscience, Université Laval, Québec City, Québec, Canada; Centre de recherche du CHU de Québec, Axe Neurosciences, Québec City, Québec, Canada
| | - Youming Lu
- Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Institute of Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Ling-Qiang Zhu
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Sino-Canada Collaborative Platform on Molecular Biology of Neurological Disease, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China; Institute of Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, P. R. China.
| |
Collapse
|
6
|
Khoonsari PE, Häggmark A, Lönnberg M, Mikus M, Kilander L, Lannfelt L, Bergquist J, Ingelsson M, Nilsson P, Kultima K, Shevchenko G. Analysis of the Cerebrospinal Fluid Proteome in Alzheimer's Disease. PLoS One 2016; 11:e0150672. [PMID: 26950848 PMCID: PMC4780771 DOI: 10.1371/journal.pone.0150672] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 02/16/2016] [Indexed: 12/24/2022] Open
Abstract
Alzheimer’s disease is a neurodegenerative disorder accounting for more than 50% of cases of dementia. Diagnosis of Alzheimer’s disease relies on cognitive tests and analysis of amyloid beta, protein tau, and hyperphosphorylated tau in cerebrospinal fluid. Although these markers provide relatively high sensitivity and specificity for early disease detection, they are not suitable for monitor of disease progression. In the present study, we used label-free shotgun mass spectrometry to analyse the cerebrospinal fluid proteome of Alzheimer’s disease patients and non-demented controls to identify potential biomarkers for Alzheimer’s disease. We processed the data using five programs (DecyderMS, Maxquant, OpenMS, PEAKS, and Sieve) and compared their results by means of reproducibility and peptide identification, including three different normalization methods. After depletion of high abundant proteins we found that Alzheimer’s disease patients had lower fraction of low-abundance proteins in cerebrospinal fluid compared to healthy controls (p<0.05). Consequently, global normalization was found to be less accurate compared to using spiked-in chicken ovalbumin for normalization. In addition, we determined that Sieve and OpenMS resulted in the highest reproducibility and PEAKS was the programs with the highest identification performance. Finally, we successfully verified significantly lower levels (p<0.05) of eight proteins (A2GL, APOM, C1QB, C1QC, C1S, FBLN3, PTPRZ, and SEZ6) in Alzheimer’s disease compared to controls using an antibody-based detection method. These proteins are involved in different biological roles spanning from cell adhesion and migration, to regulation of the synapse and the immune system.
Collapse
Affiliation(s)
- Payam Emami Khoonsari
- Department of Medical Sciences, Cancer Pharmacology and Computational Medicine, Uppsala University, Uppsala, Sweden
| | - Anna Häggmark
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Maria Lönnberg
- Analytical Chemistry, Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden
| | - Maria Mikus
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Lena Kilander
- Department of Public Health/Geriatrics, Uppsala University, Uppsala, Sweden
| | - Lars Lannfelt
- Department of Public Health/Geriatrics, Uppsala University, Uppsala, Sweden
| | - Jonas Bergquist
- Analytical Chemistry, Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden
| | - Martin Ingelsson
- Department of Public Health/Geriatrics, Uppsala University, Uppsala, Sweden
| | - Peter Nilsson
- Affinity Proteomics, Science for Life Laboratory, School of Biotechnology, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Kim Kultima
- Department of Medical Sciences, Cancer Pharmacology and Computational Medicine, Uppsala University, Uppsala, Sweden
- * E-mail:
| | - Ganna Shevchenko
- Analytical Chemistry, Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden
| |
Collapse
|
7
|
Lee LH, Godenschwege TA. Structure-function analyses of tyrosine phosphatase PTP69D in giant fiber synapse formation of Drosophila. Mol Cell Neurosci 2014; 64:24-31. [PMID: 25433167 DOI: 10.1016/j.mcn.2014.11.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 10/17/2014] [Accepted: 11/23/2014] [Indexed: 10/24/2022] Open
Abstract
PTP69D is a receptor protein tyrosine phosphatase (RPTP) with two intracellular catalytic domains (Cat1 and Cat2) and has been shown to play a role in axon guidance of embryonic motoneurons as well as targeting of photoreceptor neurons in the visual system of Drosophila melanogaster. Here, we characterized the developmental role of PTP69D in the giant fiber (GF) neurons, two interneurons in the central nervous system (CNS) that control the escape response of the fly. Our studies revealed that PTP69D has a function in synaptic terminal growth in the CNS. We found that missense mutations in the first immunoglobulin (Ig) domain and in the Cat1 domain, present in Ptp69D10 and Ptp69D20 mutants, respectively, did not affect axon guidance or targeting but resulted in stunted terminal growth of the GFs. Cell autonomous rescue experiments demonstrated a function for the Cat1 and the first Ig domain of PTP69D in the GFs but not in its postsynaptic target neurons. In addition, complementation studies and structure-function analyses revealed that for GF terminal growth Cat1 function of PTP69D requires the immunoglobulin and the Cat2 domains, but not the fibronectin III or the membrane proximal region domains. In contrast, the fibronectin III but not the immunoglobulin domains were previously shown to be essential for axon targeting of photoreceptor neurons. Thus, our studies uncover a novel role for PTP69D in synaptic terminal growth in the CNS that is mechanistically distinct from its function in photoreceptor targeting.
Collapse
Affiliation(s)
- LaTasha H Lee
- Department of Biological Sciences, Florida Atlantic University, John D MacArthur Campus, Jupiter, FL, USA
| | - Tanja A Godenschwege
- Department of Biological Sciences, Florida Atlantic University, John D MacArthur Campus, Jupiter, FL, USA.
| |
Collapse
|
8
|
Kim HN, Roh SJ, Sung YA, Chung HW, Lee JY, Cho J, Shin H, Kim HL. Genome-wide association study of the five-factor model of personality in young Korean women. J Hum Genet 2013; 58:667-74. [PMID: 23903073 DOI: 10.1038/jhg.2013.75] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 05/30/2013] [Accepted: 06/07/2013] [Indexed: 12/30/2022]
Abstract
Personality is a determinant of behavior and lifestyle associated with health and human diseases. Although personality is known to be a heritable trait, its polygenic nature has made the identification of genetic variants elusive. We performed a genome-wide association study on 1089 Korean women aged 18-40 years whose personality traits were measured with the Revised NEO Personality Inventory for the five-factor model of personality. To reduce environmental factors that may influence personality traits, this study was restricted to young adult women. In the discovery phase, we identified variants of PTPRD (protein tyrosine phosphatase, receptor type D) that associated this gene with the Openness domain. Other genes that were previously reported to be associated with neurological phenotypes were also associated with personality traits. In particular, DRD1 and OR1A2 were linked to Neuroticism, NKAIN2 with Extraversion, HTR5A with Openness and DRD3 with Agreeableness. Data from our replication study of 2090 subjects confirmed the association between OR1A2 and Neuroticism. We first identified and confirmed a novel region on OR1A2 associated with Neuroticism [corrected]. Candidate genes for psychiatric disorders were also enriched. These findings contribute to our understanding of the genetic architecture of personality traits and provide critical clues to the neurobiological mechanisms that influence them.
Collapse
Affiliation(s)
- Han-Na Kim
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Korea
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Protein tyrosine phosphatases PTPδ, PTPσ, and LAR: presynaptic hubs for synapse organization. Trends Neurosci 2013; 36:522-34. [PMID: 23835198 DOI: 10.1016/j.tins.2013.06.002] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 06/03/2013] [Accepted: 06/11/2013] [Indexed: 02/04/2023]
Abstract
Synapse development requires differentiation of presynaptic neurotransmitter release sites and postsynaptic receptive apparatus coordinated by synapse organizing proteins. In addition to the well-characterized neurexins, recent studies identified presynaptic type IIa receptor-type protein tyrosine phosphatases (RPTPs) as mediators of presynaptic differentiation and triggers of postsynaptic differentiation, thus extending the roles of RPTPs from axon outgrowth and guidance. Similarly to neurexins, RPTPs exist in multiple isoforms generated by alternative splicing that interact in a splice-selective code with diverse postsynaptic partners. The parallel RPTP and neurexin hub design facilitates synapse self-assembly through cooperation, pairs presynaptic similarity with postsynaptic diversity, and balances excitation with inhibition. Upon mutation of individual genes in neuropsychiatric disorders, imbalance of this synaptic organizing network may contribute to impaired cognitive function.
Collapse
|
10
|
Santhanam A, Liang SY, Chen DY, Chen GC, Meng TC. Midgut-enriched receptor protein tyrosine phosphatase PTP52F is required forDrosophiladevelopment during larva-pupa transition. FEBS J 2012; 280:476-88. [DOI: 10.1111/j.1742-4658.2012.08696.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
|
11
|
Besser M, Horvat-Bröcker A, Eysel UT, Faissner A. Differential expression of receptor protein tyrosine phosphatases accompanies the reorganisation of the retina upon laser lesion. Exp Brain Res 2009; 198:37-47. [PMID: 19639307 DOI: 10.1007/s00221-009-1932-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Accepted: 06/29/2009] [Indexed: 12/14/2022]
Abstract
The regulation of protein phosphorylation plays an essential role in virtually all aspects of eukaryotic development. Beginning with the regulation of the cell cycle to cellular proliferation and differentiation, the delicate balance between the phosphorylating activity of kinases and the dephosphorylation by phosphatases controls the outcome of many signal transduction cascades. The generation of cellular diversity occurs in an environment that is structured by the extracellular matrix (ECM) which forms a surrounding niche for stem and progenitor cells. Cell-cell and cell-matrix interactions elicit specific signaling pathways that control cellular behavior. In pathological situations such as neural degenerating diseases, gene expression patterns and finally the composition of the ECM change dramatically. This leads to changes of cell behavior and finally results in the failure of regeneration and functional restoration in the adult central nervous system. In order to study the roles of tyrosine phosphatases and ECM in this context, we analyzed the effects of laser-induced retinal injury on the regulation of the receptor protein tyrosine phosphatases (RPTP) RPTPBr7, Phogrin and RPTPbeta/zeta. The latter occurs in several isoforms, including the soluble released chondroitin sulfate proteoglycan phosphacan that is expressed in the developing retina. The receptor variants RPTPbeta/zeta(long) and RPTPbeta/zeta(short) may serve as receptors of tenascin-proteins and serve as modulators of cell intrinsic signaling in response to the ECM. Using quantitative real-time RT-PCR analysis, we show here a time-dependent pattern of gene expression of these molecules following laser lesions of the retina.
Collapse
Affiliation(s)
- Manuela Besser
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology, Ruhr-University Bochum, Universitaetsstr. 150, 44780 Bochum, Germany
| | | | | | | |
Collapse
|
12
|
Alete DE, Weeks ME, Hovanession AG, Hawadle M, Stoker AW. Cell surface nucleolin on developing muscle is a potential ligand for the axonal receptor protein tyrosine phosphatase-sigma. FEBS J 2006; 273:4668-81. [PMID: 16995858 PMCID: PMC1866192 DOI: 10.1111/j.1742-4658.2006.05471.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Reversible tyrosine phosphorylation, catalyzed by receptor tyrosine kinases and receptor tyrosine phosphatases, plays an essential part in cell signaling during axonal development. Receptor protein tyrosine phosphatase-sigma has been implicated in the growth, guidance and repair of retinal axons. This phosphatase has also been implicated in motor axon growth and innervation. Insect orthologs of receptor protein tyrosine phosphatase-sigma are also implicated in the recognition of muscle target cells. A potential extracellular ligand for vertebrate receptor protein tyrosine phosphatase-sigma has been previously localized in developing skeletal muscle. The identity of this muscle ligand is currently unknown, but it appears to be unrelated to the heparan sulfate ligands of receptor protein tyrosine phosphatase-sigma. In this study, we have used affinity chromatography and tandem MS to identify nucleolin as a binding partner for receptor protein tyrosine phosphatase-sigma in skeletal muscle tissue. Nucleolin, both from tissue lysates and in purified form, binds to receptor protein tyrosine phosphatase-sigma ectodomains. Its expression pattern also overlaps with that of the receptor protein tyrosine phosphatase-sigma-binding partner previously localized in muscle, and nucleolin can also be found in retinal basement membranes. We demonstrate that a significant amount of muscle-associated nucleolin is present on the cell surface of developing myotubes, and that two nucleolin-binding components, lactoferrin and the HB-19 peptide, can block the interaction of receptor protein tyrosine phosphatase-sigma ectodomains with muscle and retinal basement membranes in tissue sections. These data suggest that muscle cell surface-associated nucleolin represents at least part of the muscle binding site for axonal receptor protein tyrosine phosphatase-sigma and that nucleolin may also be a necessary component of basement membrane binding sites of receptor protein tyrosine phosphatase-sigma.
Collapse
Affiliation(s)
- Daniel E. Alete
- Neural Development Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| | - Mark E. Weeks
- Molecular Oncology, CRUK, Barts and The London School of Medicine and Dentistry, John Vane Centre, Charter House Square, London EC1M 6BQ, UK
| | - Ara G. Hovanession
- UPR 2228 CNRS, UFR Biomedicale-Universite Rene Descartes, 45 rue des Saints Peres, 75270 Paris Cedex 6, France
| | | | - Andrew W. Stoker
- Neural Development Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
| |
Collapse
|
13
|
Ensslen-Craig SE, Brady-Kalnay SM. Receptor protein tyrosine phosphatases regulate neural development and axon guidance. Dev Biol 2004; 275:12-22. [PMID: 15464569 DOI: 10.1016/j.ydbio.2004.08.009] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Revised: 08/05/2004] [Accepted: 08/08/2004] [Indexed: 01/06/2023]
Abstract
The regulation of tyrosine phosphorylation is recognized as an important developmental mechanism. Both addition and removal of phosphate moieties on tyrosine residues are tightly regulated during development. Originally, most attention focused on the role of tyrosine kinases during development, but more recently, the developmental importance of tyrosine phosphatases has been gaining interest. Receptor protein tyrosine phosphatases (RPTPs) are of particular interest to developmental biologists because the extracellular domains of RPTPs are similar to those of cell adhesion molecules (CAMs). This suggests that RPTPs may have functions in development similar to CAMs. This review focuses on the role of RPTPs in development of the nervous system in processes such as axon guidance, synapse formation, and neural tissue morphogenesis.
Collapse
Affiliation(s)
- Sonya E Ensslen-Craig
- Department of Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, OH 44106-4960, USA
| | | |
Collapse
|
14
|
Kolkman MJM, Streijger F, Linkels M, Bloemen M, Heeren DJ, Hendriks WJAJ, Van der Zee CEEM. Mice lacking leukocyte common antigen-related (LAR) protein tyrosine phosphatase domains demonstrate spatial learning impairment in the two-trial water maze and hyperactivity in multiple behavioural tests. Behav Brain Res 2004; 154:171-82. [PMID: 15302123 DOI: 10.1016/j.bbr.2004.02.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2003] [Revised: 02/05/2004] [Accepted: 02/06/2004] [Indexed: 12/11/2022]
Abstract
Leukocyte common antigen-related (LAR) protein is a cell adhesion molecule-like receptor-type protein tyrosine phosphatase. We previously reported that in LAR tyrosine phosphatase-deficient (LAR-Delta P) mice the number and size of basal forebrain cholinergic neurons as well as their innervation of the hippocampal area was reduced. With the hippocampus being implicated in behavioural activity aspects, including learning and memory processes, we assessed possible phenotypic consequences of LAR phosphatase deficiency using a battery of rodent behaviour tests. Motor function and co-ordination tests as well as spatial learning ability assays did not reveal any performance differences between wildtype and LAR-Delta P mice. A spatial learning impairment was found in the difficult variant of the Morris water maze. Exploration, nestbuilding and activity tests indicated that LAR-Delta P mice were more active than wildtype littermates. The observed hyperactivity in LAR-Delta P mice could not be explained by altered anxiety or curiosity levels, and was found to be persistent throughout the nocturnal period. In conclusion, behavioural testing of the LAR-Delta P mice revealed a spatial learning impairment and a significant increase in activity.
Collapse
Affiliation(s)
- Marloes J M Kolkman
- Department of Cell Biology, Nijmegen Center for Molecular Life Sciences, UMC St. Radboud, University of Nijmegen, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
15
|
Aerne B, Ish-Horowicz D. Receptor tyrosine phosphatase psi is required for Delta/Notch signalling and cyclic gene expression in the presomitic mesoderm. Development 2004; 131:3391-9. [PMID: 15226256 DOI: 10.1242/dev.01222] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Segmentation in vertebrate embryos is controlled by a biochemical oscillator ('segmentation clock') intrinsic to the cells in the unsegmented presomitic mesoderm, and is manifested in cyclic transcription of genes involved in establishing somite polarity and boundaries. We show that the receptor protein tyrosine phosphatase psi (RPTPpsi) gene is essential for normal functioning of the somitogenesis clock in zebrafish. We show that reduction of RPTPpsi activity using morpholino antisense oligonucleotides results in severe disruption of the segmental pattern of the embryo, and loss of cyclic gene expression in the presomitic mesoderm. Analysis of cyclic genes in RPTPpsi morphant embryos indicates an important requirement for RPTPpsi in the control of the somitogenesis clock upstream of or in parallel with Delta/Notch signalling. Impairing RPTPpsi activity also interferes with convergent extension during gastrulation. We discuss this dual requirement for RPTPpsi in terms of potential functions in Notch and Wnt signalling.
Collapse
Affiliation(s)
- Birgit Aerne
- Developmental Genetics Laboratory, Cancer Research UK, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
| | | |
Collapse
|
16
|
Chang C, Yu TW, Bargmann CI, Tessier-Lavigne M. Inhibition of netrin-mediated axon attraction by a receptor protein tyrosine phosphatase. Science 2004; 305:103-6. [PMID: 15232111 DOI: 10.1126/science.1096983] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
During axon guidance, the ventral guidance of the Caenorhabditis elegans anterior ventral microtubule axon is controlled by two cues, the UNC-6/netrin attractant recognized by the UNC-40/DCC receptor and the SLT-1/slit repellent recognized by the SAX-3/robo receptor. We show here that loss-of-function mutations in clr-1 enhance netrin-dependent attraction, suppressing ventral guidance defects in slt-1 mutants. clr-1 encodes a transmembrane receptor protein tyrosine phosphatase (RPTP) that functions in AVM to inhibit signaling through the DCC family receptor UNC-40 and its effector, UNC-34/enabled. The known effects of other RPTPs in axon guidance could result from modulation of guidance receptors like UNC-40/DCC.
Collapse
Affiliation(s)
- Chieh Chang
- Department of Biological Sciences, Howard Hughes Medical Institute (HHMI), Stanford University, Stanford, CA 94305, USA
| | | | | | | |
Collapse
|
17
|
Gerling N, Culmsee C, Klumpp S, Krieglstein J. The tyrosine phosphatase inhibitor orthovanadate mimics NGF-induced neuroprotective signaling in rat hippocampal neurons. Neurochem Int 2004; 44:505-20. [PMID: 15209419 DOI: 10.1016/j.neuint.2003.08.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Activation of the high affinity neurotrophin receptor tropomyosin-related kinase A (TrkA) by nerve growth factor (NGF) leads to phosphorylation of intracellular tyrosine residues of the receptor with subsequent activation of signaling pathways involved in neuronal survival such as the phosphoinositide-3-kinase (PI3-K)/protein kinase B (PKB/Akt) pathway and the mitogen-activated protein kinase (MAPK) cascade. In the present study, we tested whether inhibition of protein-tyrosine phosphatases (PTP) by orthovanadate could enhance tyrosine phosphorylation of TrkA thereby stimulating NGF-like survival signaling in embryonic hippocampal neurons. We found that the PTP inhibitor orthovanadate (1 microM) enhanced TrkA phosphorylation and protected neurons against staurosporine (STS)-induced apoptosis in a time-and concentration-dependent manner. Inhibition of PTP enhanced TrkA phosphorylation also in the presence of NGF antibodies indicating that NGF binding to TrkA was not required for the effects of orthovanadate. Moreover, orthovanadate enhanced phosphorylation of Akt and the MAPK Erk1/2 suggesting that the signaling pathways involved in the protective effect were similar to those activated by NGF. Accordingly, inhibition of PI3-K by wortmannin and MAPK-kinase (MEK) inhibition by UO126 abolished the neuroprotective effects. In conclusion, the results indicate that orthovanadate mimics the effect of NGF on survival signaling pathways in hippocampal neurons. Thus, PTP inhibition appears to be an appropriate strategy to trigger neuroprotective signaling pathways downstream of neurotrophin receptors.
Collapse
Affiliation(s)
- Norbert Gerling
- Institute for Pharmacology and Toxicology, Philipps-University Marburg, Fachbereich Pharmazie, Ketzerbach 63, Marburg D-350372, Germany
| | | | | | | |
Collapse
|
18
|
Rougon G, Hobert O. New insights into the diversity and function of neuronal immunoglobulin superfamily molecules. Annu Rev Neurosci 2003; 26:207-38. [PMID: 12598678 DOI: 10.1146/annurev.neuro.26.041002.131014] [Citation(s) in RCA: 175] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Immunoglobulin superfamily (IgSF) proteins are implicated in diverse steps of brain development, including neuronal migration, axon pathfinding, target recognition and synapse formation, as well as in the maintenance and function of neuronal networks in the adult. We provide here a review of recent findings on the diversity and the role of transmembrane and secreted members of IgSF proteins in the nervous system. We illustrate that the complexity of IgSF protein function results from various different levels of regulation including regulation of gene expression, protein localization, and protein interactions.
Collapse
Affiliation(s)
- Genevieve Rougon
- Laboratoire NMDA CNRS UMR 6156, Universite de la Mediterranee, Institut de Biologie du Developpement (IBDM), Marseille Cedex 9, 13288 France.
| | | |
Collapse
|
19
|
Hudson AM, Cooley L. Understanding the function of actin-binding proteins through genetic analysis of Drosophila oogenesis. Annu Rev Genet 2003; 36:455-88. [PMID: 12429700 DOI: 10.1146/annurev.genet.36.052802.114101] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Much of our knowledge of the actin cytoskeleton has been derived from biochemical and cell biological approaches, through which actin-binding proteins have been identified and their in vitro interactions with actin have been characterized. The study of actin-binding proteins (ABPs) in genetic model systems has become increasingly important for validating and extending our understanding of how these proteins function. New ABPs have been identified through genetic screens, and genetic results have informed the interpretation of in vitro experiments. In this review, we describe the molecular and ultrastructural characteristics of the actin cytoskeleton in the Drosophila ovary, and discuss recent genetic analyses of actin-binding proteins that are required for oogenesis.
Collapse
Affiliation(s)
- Andrew M Hudson
- Departments of Genetics Yale University School of Medicine, P.O. Box 208005, New Haven, Connecticut 06520-8005, USA.
| | | |
Collapse
|
20
|
Aerne B, Stoker A, Ish-Horowicz D. Chick receptor tyrosine phosphatase Psi is dynamically expressed during somitogenesis. Gene Expr Patterns 2003; 3:325-9. [PMID: 12799079 DOI: 10.1016/s1567-133x(03)00038-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
To study the role of receptor tyrosine phosphatases in vertebrate development, in particular somitogenesis, we have cloned chick receptor tyrosine phosphatase Psi (cRPTPPsi). cRPTPPsi is expressed in a dynamic fashion in the somites to-be-formed and uniformly throughout the presomitic mesoderm. In differentiating somites, cRPTPPsi expression gets restricted to the dermomyotome. In addition cRPTPPsi is expressed in the developing intermediate mesoderm, in neurogenic and sensory organs, the limb bud and the developing heart.
Collapse
Affiliation(s)
- Birgit Aerne
- Developmental Genetics Laboratory, Cancer Research UK, Lincoln's Inn Fields, WC2A 3PX London, UK.
| | | | | |
Collapse
|
21
|
Leukocyte antigen-related protein tyrosine phosphatase receptor: a small ectodomain isoform functions as a homophilic ligand and promotes neurite outgrowth. J Neurosci 2003. [PMID: 12716943 DOI: 10.1523/jneurosci.23-08-03353.2003] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The identities of ligands interacting with protein tyrosine phosphatase (PTP) receptors to regulate neurite outgrowth remain mainly unknown. Analysis of cDNA and genomic clones encoding the rat leukocyte common antigen-related (LAR) PTP receptor predicted a small, approximately 11 kDa ectodomain isoform, designated LARFN5C, containing a novel N terminal followed by a C-terminal segment of the LAR fifth fibronectin type III domain. RT-PCR and Northern blot analysis confirmed the presence of LARFN5C transcripts in brain. Transfection of COS cells with LARFN5C-Fc cDNA resulted in expression of the predicted protein, and Western blot analysis verified expression of approximately 11 kDa LARFN5C protein in vivo and its developmental regulation. Beads coated with rLARFN5C demonstrated aggregation consistent with homophilic binding, and pull-down and immunoprecipitation assays demonstrated that rLARFN5C associates with the LAR receptor. rLARFN5C binding to COS cells was dependent on LAR expression, and rLARFN5C binding to LAR +/+ hippocampal neurons was fivefold greater than that found by using LAR-deficient (-/-) neurons. Substratum-bound rLARFN5C had potent neurite-promoting effects on LAR +/+ neurons, with a fivefold loss in potency with the use of LAR -/- neurons. rLARFN5C in solution at low nanomolar concentrations inhibited neurite outgrowth induced by substratum-bound rLARFN5C, consistent with receptor-based function. These studies suggest that a small ectodomain isoform of a PTP receptor can function as a ligand for the same receptor to promote neurite outgrowth.
Collapse
|
22
|
Takahashi T, Takahashi K, St John PL, Fleming PA, Tomemori T, Watanabe T, Abrahamson DR, Drake CJ, Shirasawa T, Daniel TO. A mutant receptor tyrosine phosphatase, CD148, causes defects in vascular development. Mol Cell Biol 2003; 23:1817-31. [PMID: 12588999 PMCID: PMC151692 DOI: 10.1128/mcb.23.5.1817-1831.2003] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vascularization defects in genetic recombinant mice have defined critical roles for a number of specific receptor tyrosine kinases. Here we evaluated whether an endothelium-expressed receptor tyrosine phosphatase, CD148 (DEP-1/PTPeta), participates in developmental vascularization. A mutant allele, CD148(DeltaCyGFP), was constructed to eliminate CD148 phosphatase activity by in-frame replacement of cytoplasmic sequences with enhanced green fluorescent protein sequences. Homozygous mutant mice died at midgestation, before embryonic day 11.5 (E11.5), with vascularization failure marked by growth retardation and disorganized vascular structures. Structural abnormalities were observed as early as E8.25 in the yolk sac, prior to the appearance of intraembryonic defects. Homozygous mutant mice displayed enlarged vessels comprised of endothelial cells expressing markers of early differentiation, including VEGFR2 (Flk1), Tal1/SCL, CD31, ephrin-B2, and Tie2, with notable lack of endoglin expression. Increased endothelial cell numbers and mitotic activity indices were demonstrated. At E9.5, homozygous mutant embryos showed homogeneously enlarged primitive vessels defective in vascular remodeling and branching, with impaired pericyte investment adjacent to endothelial structures, in similarity to endoglin-deficient embryos. Developing cardiac tissues showed expanded endocardial projections accompanied by defective endocardial cushion formation. These findings implicate a member of the receptor tyrosine phosphatase family, CD148, in developmental vascular organization and provide evidence that it regulates endothelial proliferation and endothelium-pericyte interactions.
Collapse
Affiliation(s)
- Takamune Takahashi
- Nephrology Division and Center for Vascular Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Beltran PJ, Bixby JL, Masters BA. Expression of PTPRO during mouse development suggests involvement in axonogenesis and differentiation of NT-3 and NGF-dependent neurons. J Comp Neurol 2003; 456:384-95. [PMID: 12532410 DOI: 10.1002/cne.10532] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Competition and cooperation between type II and type III receptor protein tyrosine phosphatases (RPTPs) regulate axon extension and pathfinding in Drosophila. The first step to investigate whether RPTPs influence axon growth in the more complex vertebrate nervous system is to identify which neurons express a particular RPTP. We studied the expression of mouse PTPRO, a type III RPTP with an extracellular region containing eight fibronectin type III domains, during embryogenesis and after birth. Mouse PTPRO mRNA is expressed exclusively in two cell types: neurons and kidney podocytes. Maximal expression in the brain was coincident with mid to late gestation and axonogenesis in the brain. We cloned two cDNAs, including a splice variant without sequence coding of 28 amino acids within the juxtamembrane domain that was found mostly in kidney. In situ hybridization detected mPTPRO mRNA in the cerebral cortex, olfactory bulb and nucleus, hippocampus, motor neurons, and the spinal cord midline. In addition, mPTPRO mRNA was found throughout dorsal root, cranial, and sympathetic ganglia and within kidney glomeruli. Mouse PTPRO mRNA was observed in neuron populations expressing TrkA, the high-affinity nerve growth factor receptor, or TrkC, the neurotrophin-3 receptor, and immunoreactive mPTPRO and TrkC colocalized in large dorsal root ganglia proprioceptive neurons. Our results suggest that mPTPRO is involved in the differentiation and axonogenesis of central and peripheral nervous system neurons, where it is in a position to modulate intracellular responses to neurotrophin-3 and/or nerve growth factor.
Collapse
Affiliation(s)
- Pedro J Beltran
- The Neuroscience Program and Department of Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, Florida 33136, USA
| | | | | |
Collapse
|
24
|
Kalirin Dbl-homology guanine nucleotide exchange factor 1 domain initiates new axon outgrowths via RhoG-mediated mechanisms. J Neurosci 2002. [PMID: 12177196 DOI: 10.1523/jneurosci.22-16-06980.2002] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The large multidomain Kalirin and Trio proteins containing dual Rho GTPase guanine nucleotide exchange factor (GEF) domains have been implicated in the regulation of neuronal fiber extension and pathfinding during development. In mammals, Kalirin is expressed predominantly in the nervous system, whereas Trio, broadly expressed throughout the body, is expressed at a lower level in the nervous system. To evaluate the role of Kalirin in fiber initiation and outgrowth, we microinjected cultured sympathetic neurons with vectors encoding Kalirin or with Kalirin antisense oligonucleotides, and we assessed neuronal fiber growth in a serum-free, satellite cell-free environment. Kalirin antisense oligonucleotides blocked the continued extension of preexisting axons. Kalirin overexpression induced the prolific sprouting of new axonal fibers that grew at the normal rate; the activity of Kalirin was entirely dependent on the activity of the first GEF domain. KalGEF1-induced sprouting of new fibers from lamellipodial structures was accompanied by extensive actin cytoskeleton reorganization. The kalGEF1 phenotype was mimicked by constitutively active RhoG and was blocked by RhoG inhibitors. Constitutively active Rac1, RhoA, and Cdc42 were unable to initiate new axons, whereas dominant-negative Rac1, RhoA, and Cdc42 failed to block axon sprouting. Thus Kalirin, acting via RhoG in a novel manner, plays a central role in establishing the morphological phenotypic diversity that is essential to the connectivity of the developing nervous system.
Collapse
|
25
|
Muda M, Worby CA, Simonson-Leff N, Clemens JC, Dixon JE. Use of double-stranded RNA-mediated interference to determine the substrates of protein tyrosine kinases and phosphatases. Biochem J 2002; 366:73-7. [PMID: 12014990 PMCID: PMC1222762 DOI: 10.1042/bj20020298] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2002] [Revised: 05/02/2002] [Accepted: 05/16/2002] [Indexed: 11/17/2022]
Abstract
Despite the wealth of information generated by genome-sequencing projects, the identification of in vivo substrates of specific protein kinases and phosphatases is hampered by the large number of candidate enzymes, overlapping enzyme specificity and sequence similarity. In the present study, we demonstrate the power of RNA interference (RNAi) to dissect signal transduction cascades involving specific kinases and phosphatases. RNAi is used to identify the cellular tyrosine kinases upstream of the phosphorylation of Down-Syndrome cell-adhesion molecule (Dscam), a novel cell-surface molecule of the immunoglobulin-fibronectin super family, which has been shown to be important for axonal path-finding in Drosophila. Tyrosine phosphorylation of Dscam recruits the Src homology 2 domain of the adaptor protein Dock to the receptor. Dock, the ortho- logue of mammalian Nck, is also essential for correct axonal path-finding in Drosophila. We further determined that Dock is tyrosine-phosphorylated in vivo and identified DPTP61F as the protein tyrosine phosphatase responsible for maintaining Dock in its non-phosphorylated state. The present study illustrates the versatility of RNAi in the identification of the physiological substrates for protein kinases and phosphatases.
Collapse
Affiliation(s)
- Marco Muda
- Serono Reproductive Biology Institute, Inc., Randolph, MA 02368, U.S.A
| | | | | | | | | |
Collapse
|
26
|
Lei G, Xue S, Chéry N, Liu Q, Xu J, Kwan CL, Fu YP, Lu YM, Liu M, Harder KW, Yu XM. Gain control of N-methyl-D-aspartate receptor activity by receptor-like protein tyrosine phosphatase alpha. EMBO J 2002; 21:2977-89. [PMID: 12065411 PMCID: PMC126051 DOI: 10.1093/emboj/cdf292] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Src kinase regulation of N-methyl-D-aspartate (NMDA) subtype glutamate receptors in the central nervous system (CNS) has been found to play an important role in processes related to learning and memory, ethanol sensitivity and epilepsy. However, little is known regarding the mechanisms underlying the regulation of Src family kinase activity in the control of NMDA receptors. Here we report that the distal phosphatase domain (D2) of protein tyrosine phosphatase alpha (PTPalpha) binds to the PDZ2 domain of post-synaptic density 95 (PSD95). Thus, Src kinase, its activator (PTPalpha) and substrate (NMDA receptors) are linked by the same scaffold protein, PSD95. Removal of PTPalpha does not affect the association of Src with NMDA receptors, but turns off the constitutive regulation of NMDA receptors by the kinase. Further more, we found that application of the PTPalpha catalytic domains (D1 + D2) into neurones enhances NMDA receptor-mediated synaptic responses. Conversely, the blockade of endogenous PTPalpha inhibits NMDA receptor activity and the induction of long-term potentiation in hippocampal neurones. Thus, PTPalpha is a novel up-regulator of synaptic strength in the CNS.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Yang-Ping Fu
- Center for Addiction and Mental Health, Faculty of Dentistry and Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8,
Neuroscience Research Group, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Calgary, T2N 4N1, Division of Cellular and Molecular Biology, University Health Network, Toronto General Hospital, Toronto, Ontario, M5G 2C4, Canada and Ludwig Institute for Cancer Research, Royal Melbourne Hospital, Victoria 3050, Australia Corresponding author e-mail:
| | - You-Ming Lu
- Center for Addiction and Mental Health, Faculty of Dentistry and Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8,
Neuroscience Research Group, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Calgary, T2N 4N1, Division of Cellular and Molecular Biology, University Health Network, Toronto General Hospital, Toronto, Ontario, M5G 2C4, Canada and Ludwig Institute for Cancer Research, Royal Melbourne Hospital, Victoria 3050, Australia Corresponding author e-mail:
| | - Mingyao Liu
- Center for Addiction and Mental Health, Faculty of Dentistry and Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8,
Neuroscience Research Group, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Calgary, T2N 4N1, Division of Cellular and Molecular Biology, University Health Network, Toronto General Hospital, Toronto, Ontario, M5G 2C4, Canada and Ludwig Institute for Cancer Research, Royal Melbourne Hospital, Victoria 3050, Australia Corresponding author e-mail:
| | - Kenneth W. Harder
- Center for Addiction and Mental Health, Faculty of Dentistry and Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8,
Neuroscience Research Group, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Calgary, T2N 4N1, Division of Cellular and Molecular Biology, University Health Network, Toronto General Hospital, Toronto, Ontario, M5G 2C4, Canada and Ludwig Institute for Cancer Research, Royal Melbourne Hospital, Victoria 3050, Australia Corresponding author e-mail:
| | - Xian-Min Yu
- Center for Addiction and Mental Health, Faculty of Dentistry and Department of Psychiatry, University of Toronto, Toronto, Ontario, M5T 1R8,
Neuroscience Research Group, Department of Physiology and Biophysics, Faculty of Medicine, University of Calgary, Calgary, T2N 4N1, Division of Cellular and Molecular Biology, University Health Network, Toronto General Hospital, Toronto, Ontario, M5G 2C4, Canada and Ludwig Institute for Cancer Research, Royal Melbourne Hospital, Victoria 3050, Australia Corresponding author e-mail:
| |
Collapse
|
27
|
Wyszynski M, Kim E, Dunah AW, Passafaro M, Valtschanoff JG, Serra-Pagès C, Streuli M, Weinberg RJ, Sheng M. Interaction between GRIP and liprin-alpha/SYD2 is required for AMPA receptor targeting. Neuron 2002; 34:39-52. [PMID: 11931740 DOI: 10.1016/s0896-6273(02)00640-2] [Citation(s) in RCA: 212] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Interaction with the multi-PDZ protein GRIP is required for the synaptic targeting of AMPA receptors, but the underlying mechanism is unknown. We show that GRIP binds to the liprin-alpha/SYD2 family of proteins that interact with LAR receptor protein tyrosine phosphatases (LAR-RPTPs) and that are implicated in presynaptic development. In neurons, liprin-alpha and LAR-RPTP are enriched at synapses and coimmunoprecipitate with GRIP and AMPA receptors. Dominant-negative constructs that interfere with the GRIP-liprin interaction disrupt the surface expression and dendritic clustering of AMPA receptors in cultured neurons. Thus, by mediating the targeting of liprin/GRIP-associated proteins, liprin-alpha is important for postsynaptic as well as presynaptic maturation.
Collapse
Affiliation(s)
- Michael Wyszynski
- Department of Neurobiology and Howard Hughes Medical Institute, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
van der Sar AM, Zivković D, den Hertog J. Eye defects in receptor protein-tyrosine phosphatase alpha knock-down zebrafish. Dev Dyn 2002; 223:292-7. [PMID: 11836793 DOI: 10.1002/dvdy.10059] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Receptor protein-tyrosine phosphatase alpha (RPTP alpha) is highly expressed in the developing retina of different species, but little is known about its function there. Here, we report that injection of antisense morpholinos in zebrafish embryos reduced RPTP alpha expression to almost nondetectable levels up to 3 days postfertilization (dpf). RPTP alpha was detectable again from 4 dpf onward. RPTP alpha knock-down resulted in smaller eyes. Examination of sections of the retina at different developmental stages demonstrated that already at 28 hours postfertilization (hpf) fewer cells were present in the retina of RPTP alpha-morpholino-injected embryos. At 3 dpf, the layered organization of the retina was absent. In addition, the morphology and labeling with an axon specific antibody, acetylated tubulin, demonstrated that most cells appeared to be undifferentiated. Strikingly, at 5 dpf the lamination of the retina was partially restored, concomitant with re-expression of RPTP alpha protein. Although cells in the retina were now differentiated, the layering of the retina remained disrupted and significant gaps were observed in the amacrine cell layer. Therefore, knock-down of RPTP alpha protein provides evidence that RPTP alpha is essential for normal retinal development.
Collapse
Affiliation(s)
- Astrid M van der Sar
- Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Utrecht, The Netherlands
| | | | | |
Collapse
|
29
|
Aricescu AR, McKinnell IW, Halfter W, Stoker AW. Heparan sulfate proteoglycans are ligands for receptor protein tyrosine phosphatase sigma. Mol Cell Biol 2002; 22:1881-92. [PMID: 11865065 PMCID: PMC135600 DOI: 10.1128/mcb.22.6.1881-1892.2002] [Citation(s) in RCA: 169] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RPTPsigma is a cell adhesion molecule-like receptor protein tyrosine phosphatase involved in nervous system development. Its avian orthologue, known as cPTPsigma or CRYPalpha, promotes intraretinal axon growth and controls the morphology of growth cones. The molecular mechanisms underlying the functions of cPTPsigma are still to be determined, since neither its physiological ligand(s) nor its substrates have been described. Nevertheless, a major class of ligand(s) is present in the retinal basal lamina and glial endfeet, the potent native growth substrate for retinal axons. We demonstrate here that cPTPsigma is a heparin-binding protein and that its basal lamina ligands include the heparan sulfate proteoglycans (HSPGs) agrin and collagen XVIII. These molecules interact with high affinity with cPTPsigma in vitro, and this binding is totally dependent upon their heparan sulfate chains. Using molecular modelling and site-directed mutagenesis, a binding site for heparin and heparan sulfate was identified in the first immunoglobulin-like domain of cPTPsigma. HSPGs are therefore a novel class of heterotypic ligand for cPTPsigma, suggesting that cPTPsigma signaling in axons and growth cones is directly responsive to matrix-associated cues.
Collapse
Affiliation(s)
- A Radu Aricescu
- Neural Development Unit, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, United Kingdom
| | | | | | | |
Collapse
|
30
|
van der Sar A, Betist M, de Fockert J, Overvoorde J, Zivković D, den Hertog J. Expression of receptor protein-tyrosine phosphatase alpha, sigma and LAR during development of the zebrafish embryo. Mech Dev 2001; 109:423-6. [PMID: 11731262 DOI: 10.1016/s0925-4773(01)00545-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Receptor protein-tyrosine phosphatases (RPTPs) are key players in Drosophila development. To study the role of RPTPs in vertebrate development, we have cloned zebrafish (zf) RPTPs, including RPTP alpha (RPTPalpha), RPTP sigma (RPTPsigma) and LAR. These three RPTPs are broadly transcribed in early development. At 24h post fertilisation (hpf), all three genes are expressed in the nervous system in partially overlapping patterns. At 3 days post fertilisation zf-RPTPalpha and zf-LAR show similar expression patterns in the central nervous system (CNS), the pharyngeal arches, the pectoral fins and the spinal cord. Interestingly, zf-LAR is uniquely expressed in the neuromast cells, whereas zf-RPTPsigma expression is confined to the central nervous system.
Collapse
Affiliation(s)
- A van der Sar
- Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands
| | | | | | | | | | | |
Collapse
|
31
|
Tong J, Killeen M, Steven R, Binns KL, Culotti J, Pawson T. Netrin stimulates tyrosine phosphorylation of the UNC-5 family of netrin receptors and induces Shp2 binding to the RCM cytodomain. J Biol Chem 2001; 276:40917-25. [PMID: 11533026 DOI: 10.1074/jbc.m103872200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Caenorhabditis elegans UNC-5 and its mammalian homologues such as RCM are receptors for the secreted axon guidance cue UNC-6/netrin and are required to mediate the repulsive effects of UNC-6/netrin on growth cones. We find that C. elegans UNC-5 and mouse RCM are phosphorylated on tyrosine in vivo. C. elegans UNC-5 tyrosine phosphorylation is reduced in unc-6 null mutants, and RCM tyrosine phosphorylation is induced by netrin-1 in transfected HEK-293 cells, demonstrating that phosphorylation of UNC-5 proteins is enhanced by UNC-6/netrin stimulation in both worms and mammalian cells. An activated Src tyrosine kinase induces phosphorylation of RCM at multiple cytoplasmic tyrosine residues creating potential binding sites for cytoplasmic signaling proteins. Indeed, the NH2-terminal SH2 domain of the Shp2 tyrosine phosphatase bound specifically to a Tyr(568) RCM phosphopeptide. Furthermore, Shp2 associated with RCM in a netrin-dependent manner in transfected cells, and co-immunoprecipitated with RCM from an embryonic mouse brain lysate. A Y568F mutant RCM receptor failed to bind Shp2 and was more highly phosphorylated on tyrosine than the wild type receptor. These results suggest that netrin-stimulated phosphorylation of RCM Tyr(568) recruits Shp2 to the cell membrane where it can potentially modify RCM phosphorylation and function.
Collapse
Affiliation(s)
- J Tong
- Program in Molecular Biology and Cancer, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
| | | | | | | | | | | |
Collapse
|
32
|
Clandinin TR, Lee CH, Herman T, Lee RC, Yang AY, Ovasapyan S, Zipursky SL. Drosophila LAR regulates R1-R6 and R7 target specificity in the visual system. Neuron 2001; 32:237-48. [PMID: 11683994 DOI: 10.1016/s0896-6273(01)00474-3] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Different classes of photoreceptor neurons (R cells) in the Drosophila compound eye connect to specific targets in the optic lobe. Using a behavioral screen, we identified LAR, a receptor tyrosine phosphatase, as being required for R cell target specificity. In LAR mutant mosaic eyes, R1-R6 cells target to the lamina correctly, but fail to choose the correct pattern of target neurons. Although mutant R7 axons initially project to the correct layer of the medulla, they retract into inappropriate layers. Using single cell mosaics, we demonstrate that LAR controls targeting of R1-R6 and R7 in a cell-autonomous fashion. The phenotypes of LAR mutant R cells are strikingly similar to those seen in N-cadherin mutants.
Collapse
Affiliation(s)
- T R Clandinin
- Department of Biological Chemistry, Howard Hughes Medical Institute, University of California, Los Angeles, School of Medicine, CA 90095, USA
| | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
PDZ domains are modular protein interaction domains that bind in a sequence-specific fashion to short C-terminal peptides or internal peptides that fold in a beta-finger. The diversity of PDZ binding specificities can be explained by variable amino acids lining the peptide-binding groove of the PDZ domain. Abundantly represented in Caenorhabditis elegans, Drosophila melanogaster, and mammalian genomes, PDZ domains are frequently found in multiple copies or are associated with other protein-binding motifs in multidomain scaffold proteins. PDZ-containing proteins are typically involved in the assembly of supramolecular complexes that perform localized signaling functions at particular subcellular locations. Organization around a PDZ-based scaffold allows the stable localization of interacting proteins and enhances the rate and fidelity of signal transduction within the complex. Some PDZ-containing proteins are more dynamically regulated in distribution and may also be involved in the trafficking of interacting proteins within the cell.
Collapse
Affiliation(s)
- M Sheng
- Howard Hughes Medical Institute and Department of Neurobiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
| | | |
Collapse
|
34
|
Sörby M, Sandström J, Ostman A. An extracellular ligand increases the specific activity of the receptor-like protein tyrosine phosphatase DEP-1. Oncogene 2001; 20:5219-24. [PMID: 11526512 DOI: 10.1038/sj.onc.1204581] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2001] [Revised: 04/12/2001] [Accepted: 04/30/2001] [Indexed: 01/06/2023]
Abstract
Cellular growth, differentiation and migration is regulated by protein tyrosine phosphorylation. Receptor-like protein tyrosine phosphatases are thus likely to be key regulators of vital cellular processes. The regulation of these enzymes is in general poorly understood. Ligands have been identified only for a small subset of the receptor-like protein tyrosine phosphatases and in no case has upregulation of the specific activity by extracellular ligands been demonstrated. Prompted by earlier findings of ligands for receptor-like protein tyrosine phosphatases in extracellular matrix we investigated if Matrigel, a preparation of extracellular matrix proteins, contained modulators of the specific activity of the receptor-like protein tyrosine phosphatase DEP-1. Matrigel stimulation of cells increased the specific activity of immunoprecipitated DEP-1. Also, incubation of immunoprecipitated DEP-1 with Matrigel led to an increase in DEP-1 activity, which was blocked by soluble DEP-1 extracellular domain. Finally, immunoprecipitated DeltaECD-DEP-1, a mutant form of DEP-1 lacking most of the extracellular domain, failed to respond to Matrigel stimulation. These experiments identify Matrigel as a source of DEP-1 agonist(s) and provide the first evidence for upregulation of the specific activity of receptor-like protein tyrosine phosphatases by extracellular ligands.
Collapse
Affiliation(s)
- M Sörby
- Ludwig Institute for Cancer Research, Box 595, S-751 24 Uppsala, Sweden
| | | | | |
Collapse
|
35
|
The leukocyte common antigen-related protein tyrosine phosphatase receptor regulates regenerative neurite outgrowth in vivo. J Neurosci 2001. [PMID: 11438588 DOI: 10.1523/jneurosci.21-14-05130.2001] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Drosophila and leech models of nervous system development demonstrate that protein tyrosine phosphatase (PTP) receptors regulate developmental neurite outgrowth. Whether PTP receptors regulate neurite outgrowth in adult systems or in regenerative states remains unknown. The leukocyte common antigen-related (LAR) receptor is known to be present in rodent dorsal root ganglion (DRG) neurons; therefore, the well established model of postcrush sciatic nerve regeneration was used to test the hypothesis that LAR is required for neurite outgrowth in the adult mammalian nervous system. In uninjured sciatic nerves, no differences in nerve morphology and sensory function were detected between wild-type and LAR-deficient littermate transgenic mice. Sciatic nerve crush resulted in increased LAR protein expression in DRG neurons. In addition, nerve injury led to an increase in the proportion of LAR protein isoforms known to have increased binding affinity to neurite-promoting laminin-nidogen complexes. Two weeks after nerve crush, morphological analysis of distal nerve segments in LAR-deficient transgenic mice demonstrated significantly decreased densities of myelinated fibers, decreased axonal areas, and increased myelin/axon area ratios compared with littermate controls. Electron microscopy analysis revealed a significant twofold reduction in the density of regenerating unmyelinated fibers in LAR-/- nerves distal to the crush site. Sensory testing at the 2 week time point revealed a corresponding 3 mm lag in the proximal-to-distal progression of functioning sensory fibers along the distal nerve segment. These studies introduce PTP receptors as a major new gene family regulating regenerative neurite outgrowth in vivo in the adult mammalian system.
Collapse
|
36
|
Van Lieshout EM, Van der Heijden I, Hendriks WJ, Van der Zee CE. A decrease in size and number of basal forebrain cholinergic neurons is paralleled by diminished hippocampal cholinergic innervation in mice lacking leukocyte common antigen-related protein tyrosine phosphatase activity. Neuroscience 2001; 102:833-41. [PMID: 11182246 DOI: 10.1016/s0306-4522(00)00526-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The leukocyte common antigen-related (LAR) receptor, composed of an extracellular region with three immunoglobulin-like and eight fibronectin type III-like domains, and a cytoplasmic region containing two protein tyrosine phosphatase domains, is thought to play a role in axonal outgrowth and guidance during neural development. LAR mutant mice were generated completely lacking the two cytoplasmic protein tyrosine phosphatase domains, resulting in the loss of ability to bind intracellular associating proteins, but (may be) still containing the ability to perform extracellular functions. A reduction in size of basal forebrain cholinergic neurons and diminished hippocampal innervation reported for knockout mice that contain a leaky gene trap inserted into the 5' part of the LAR gene [Yeo T. T. et al. (1997) J. Neurosci. Res. 47, 348-360] warranted a computer-assisted quantitative image analysis throughout the basal forebrain and hippocampus of our LAR mutant mice. The total number, longest diameter and cell body area were calculated for the choline acetyltransferase-positive neurons in the medial septum and vertical diagonal band, and optical density measurements were performed to determine the extent of acetyl cholinesterase-positive fibre innervation of the different layers in the dentate gyrus. In LAR mutant mice, the number of cholinergic cells was significantly reduced (approximately 25%) in the vertical diagonal band. Also, the cross-sectional area of the cholinergic neurons in the medial septum and vertical diagonal band was reduced (5%). These findings were paralleled by a diminished cholinergic innervation of the supragranular (18%) and molecular (4%) layers of the dentate gyrus. Thus, LAR protein tyrosine phosphatase activity appears crucial for size, number and target projection of basal forebrain cholinergic neurons, further strengthening a role for LAR in CNS development.
Collapse
Affiliation(s)
- E M Van Lieshout
- Department of Cell Biology, Institute of Cellular Signalling, University Medical Centre St. Radboud, Adelbertusplein 1, 6525 EK, Nijmegen, The Netherlands
| | | | | | | |
Collapse
|
37
|
Zabolotny JM, Kim YB, Peroni OD, Kim JK, Pani MA, Boss O, Klaman LD, Kamatkar S, Shulman GI, Kahn BB, Neel BG. Overexpression of the LAR (leukocyte antigen-related) protein-tyrosine phosphatase in muscle causes insulin resistance. Proc Natl Acad Sci U S A 2001; 98:5187-92. [PMID: 11309481 PMCID: PMC33185 DOI: 10.1073/pnas.071050398] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Previous reports indicate that the expression and/or activity of the protein-tyrosine phosphatase (PTP) LAR are increased in insulin-responsive tissues of obese, insulin-resistant humans and rodents, but it is not known whether these alterations contribute to the pathogenesis of insulin resistance. To address this question, we generated transgenic mice that overexpress human LAR, specifically in muscle, to levels comparable to those reported in insulin-resistant humans. In LAR-transgenic mice, fasting plasma insulin was increased 2.5-fold compared with wild-type controls, whereas fasting glucose was normal. Whole-body glucose disposal and glucose uptake into muscle in vivo were reduced by 39-50%. Insulin injection resulted in normal tyrosyl phosphorylation of the insulin receptor and insulin receptor substrate 1 (IRS-1) in muscle of transgenic mice. However, phosphorylation of IRS-2 was reduced by 62%, PI3' kinase activity associated with phosphotyrosine, IRS-1, or IRS-2 was reduced by 34-57%, and association of p85alpha with both IRS proteins was reduced by 39-52%. Thus, overexpression of LAR in muscle causes whole-body insulin resistance, most likely due to dephosphorylation of specific regulatory phosphotyrosines on IRS proteins. Our data suggest that increased expression and/or activity of LAR or related PTPs in insulin target tissues of obese humans may contribute to the pathogenesis of insulin resistance.
Collapse
Affiliation(s)
- J M Zabolotny
- Division of Endocrinology and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center, and Harvard Medical School, 99 Brookline Avenue, Boston, MA 02215, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Abstract
Protein tyrosine phosphatases (PTPs), the enzymes that dephosphorylate tyrosyl phosphoproteins, were initially believed to be few in number and serve a 'housekeeping' role in signal transduction. Recent work indicates that this is totally incorrect. Instead, PTPs comprise a large superfamily whose members play critical roles in a wide variety of cellular processes. Moreover, PTPs exhibit exquisite substrate specificity in vivo. Recent evidence has led us to propose that members of the PTP family achieve selectivity through different combinations of specific targeting strategies and intrinsic catalytic domain specificity.
Collapse
Affiliation(s)
- N K Tonks
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA.
| | | |
Collapse
|
39
|
Abstract
Receptor-like protein tyrosine phosphatases (RPTPs) continue to emerge as important signalling molecules in axons and their growth cones. Recent findings show that Drosophila RPTPs play key roles in guiding retinal axons and in preventing midline crossing of longitudinal axons. Vertebrate RPTPs are now implicated in controlling axon outgrowth, and preliminary evidence suggests that they too may influence axon guidance.
Collapse
Affiliation(s)
- A W Stoker
- Neural Development Unit, Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
| |
Collapse
|
40
|
Cheng S, Mao J, Rehder V. Filopodial behavior is dependent on the phosphorylation state of neuronal growth cones. CELL MOTILITY AND THE CYTOSKELETON 2000; 47:337-50. [PMID: 11093253 DOI: 10.1002/1097-0169(200012)47:4<337::aid-cm7>3.0.co;2-b] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Several lines of evidence suggest that phosphorylation events play an important role in transducing neurite outgrowth signals. Here we tested if such phosphorylation events altered filopodial dynamics on neuronal growth cones and thereby might affect pathfinding decisions. The general protein kinase inhibitor K252a caused an increase in the overall length of filopodia, thereby increasing the action radius of a growth cone. Application of specific kinase inhibitors demonstrated that myosin light chain kinase, Ca/calmodulin-dependent kinase II, and protein kinase A were likely not involved in this filopodial response. Inhibition of protein kinase C (PKC) with calphostin C or cerebroside, however, induced filopodial elongation similar to that seen with K252a. Activation of PKC with the phorbol ester PMA produced the opposite effect, namely filopodial shortening. Consistent with this finding, the protein phosphatase activator C(2)-ceramide resulted in a significant increase in filopodial length, whereas application of the protein phosphatase inhibitor okadaic acid caused the opposite effect, filopodial shortening. Lastly, the tyrosine kinase inhibitor genistein also caused filopodial elongation, and this effect could be negated by the tyrosine phosphatase inhibitor sodium ortho-vanadate. Using the calcium indicator fura-2, we further showed that these drugs did not cause a measurable change in the free intracellular calcium concentration ([Ca(2+)](i)) in growth cones. Taken together, these results suggest that the action radius of a growth cone and its resulting pathfinding abilities could be rapidly altered by contact with extracellular cues, leading to changes in the activity of protein kinases and phosphatases.
Collapse
Affiliation(s)
- S Cheng
- Biology Department, Georgia State University, Atlanta, GA 30303, USA
| | | | | |
Collapse
|
41
|
Gustafson AL, Mason I. Expression of receptor tyrosine phosphatase gamma during early development of the chick embryo. Mech Dev 2000; 98:183-6. [PMID: 11044627 DOI: 10.1016/s0925-4773(00)00463-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies in Drosophila suggest that receptor-tyrosine phosphatases are key regulators of neural development, however little is known about their expression or function in the nervous system of vertebrate embryos. In this report, we describe the expression pattern of RPTPgamma during early chick embryogenesis. Transcripts are largely restricted to the developing nervous system including oculomotor, trochlear and branchiomotor populations but are absent from spinal motor neurones. RPTPgamma is also detected in cells in the positions of hindbrain reticulospinal neurones, spinal commisural neurones and in cells with neuronal morphology in the ventral diencephalon. Within the peripheral nervous system transcripts are found in neuroblasts delaminating from epibranchial placodes and subsequently in placode-derived cranial ganglia. Outside the nervous system expression is detected in somites and transiently in the second branchial arch and the cranial mesenchyme.
Collapse
Affiliation(s)
- A L Gustafson
- MRC Centre for Developmental Neurobiology, New Hunt's House, King's College London, Guy's Campus, SEI 9RT, London, UK
| | | |
Collapse
|
42
|
Chilton JK, Stoker AW. Expression of receptor protein tyrosine phosphatases in embryonic chick spinal cord. Mol Cell Neurosci 2000; 16:470-80. [PMID: 11085882 DOI: 10.1006/mcne.2000.0887] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Receptor-like protein tyrosine phosphatases potentially play a crucial role in axon growth and targeting. We focus here on their role within the embryonic avian spinal cord, in particular the development and outgrowth of motorneurons. We have used in situ mRNA hybridization to examine the spatiotemporal expression of eight receptor-like protein tyrosine phosphatases and find that it is both dynamic and highly varied, including novel, isoform-specific expression patterns. CRYP alpha 1 is expressed in all of the ventral motorneuron pools, whereas CRYP2, RPTP gamma, and RPTP alpha are only expressed in specific subsets of these neurons. CRYP alpha 2, RPTP psi, and RPTP delta are neuronally expressed elsewhere in the cord, but not in ventral motorneurons, whereas RPTP mu is unique in being restricted to capillaries. The developmentally regulated expression of these genes strongly suggests that the encoded phosphatases play numerous roles during neurogenesis and axonogenesis in the vertebrate spinal cord.
Collapse
Affiliation(s)
- J K Chilton
- Neural Development Unit, Institute of Child Health, London, United Kingdom
| | | |
Collapse
|
43
|
Abstract
In recent years, it has become apparent that ligand-gated ion channels (ionotropic receptors) in the neuronal plasma membrane interact via their cytoplasmic domains with a multitude of intracellular proteins. Different classes of ligand-gated channels associate with distinct sets of intracellular proteins, often through specialized scaffold proteins containing PDZ domains. These specific interactions link the receptor channel to the cortical cytoskeleton and to appropriate signal transduction pathways in the cell. Thus ionotropic receptors are components of extensive protein complexes that are likely involved in the subcellular targeting, cytoskeletal anchoring, and localized clustering of the receptors at specific sites on the neuronal surface. In addition to structural functions, receptor-associated proteins can play important roles as activity modulators or downstream effectors of ligand-gated channels.
Collapse
Affiliation(s)
- M Sheng
- Department of Neurobiology, Massachusetts General Hospital, Boston, Massachusetts, USA.
| | | |
Collapse
|
44
|
The Dopamine/D1 receptor mediates the phosphorylation and inactivation of the protein tyrosine phosphatase STEP via a PKA-dependent pathway. J Neurosci 2000. [PMID: 10908600 DOI: 10.1523/jneurosci.20-15-05630.2000] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The striatal-enriched protein tyrosine phosphatase (STEP) family is expressed within dopaminoceptive neurons of the CNS and is particularly enriched within the basal ganglia and related structures. Alternative splicing produces several isoforms that are found in a number of subcellular compartments, including postsynaptic densities of medium spiny neurons. The variants include STEP(61), a membrane-associated protein, and STEP(46), a cytosolic protein. The C terminals of these two isoforms are identical, whereas the N-terminal domain of STEP(61) contains a novel 172 amino acid sequence that includes several structural motifs not present in STEP(46). Amino acid sequencing revealed a number of potential phosphorylation sites in both STEP isoforms. Therefore, we investigated the role of phosphorylation in regulating STEP activity. Both STEP(61) and STEP(46) are phosphorylated on seryl residues by a cAMP-dependent protein kinase (PKA)-mediated pathway in striatal homogenates. The specific residues phosphorylated in STEP(61) were identified by site-directed mutagenesis and tryptic phosphopeptide mapping as Ser160 and Ser221, whereas the major site of phosphorylation in STEP(46) was shown to be Ser49. Ser160 is located within the unique N terminal of STEP(61). Ser221 and Ser49 are equivalent residues present in STEP(61) and STEP(46), respectively, and are located at the center of the kinase-interacting motif that has been implicated in protein-protein interactions. Phosphorylation at this site decreases the activity of STEP in vitro by reducing its affinity for its substrate. In vivo studies using striatal slices demonstrated that the neurotransmitter dopamine leads to the phosphorylation of STEP via activation of D1 receptors and PKA.
Collapse
|
45
|
Uetani N, Kato K, Ogura H, Mizuno K, Kawano K, Mikoshiba K, Yakura H, Asano M, Iwakura Y. Impaired learning with enhanced hippocampal long-term potentiation in PTPdelta-deficient mice. EMBO J 2000; 19:2775-85. [PMID: 10856223 PMCID: PMC203365 DOI: 10.1093/emboj/19.12.2775] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Protein tyrosine phosphatase delta (PTPdelta) is a receptor-type PTP expressed in the specialized regions of the brain including the hippocampal CA2 and CA3, B lymphocytes and thymic medulla. To elucidate the physiological roles of PTPdelta, PTPdelta-deficient mice were produced by gene targeting. It was found that PTPdelta-deficient mice were semi-lethal due to insufficient food intake. They also exhibited learning impairment in the Morris water maze, reinforced T-maze and radial arm maze tasks. Interestingly, although the histology of the hippocampus appeared normal, the magnitudes of long-term potentiation (LTP) induced at hippocampal CA1 and CA3 synapses were significantly enhanced in PTPdelta-deficient mice, with augmented paired-pulse facilitation in the CA1 region. Thus, it was shown that PTPdelta plays important roles in regulating hippocampal LTP and learning processes, and that hippocampal LTP does not necessarily positively correlate with spatial learning ability. To our knowledge, this is the first report of a specific PTP involved in the regulation of synaptic plasticity or in the processes regulating learning and memory.
Collapse
Affiliation(s)
- N Uetani
- Center for Experimental Medicine, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Althaus HH, Richter-Landsberg C. Glial cells as targets and producers of neurotrophins. INTERNATIONAL REVIEW OF CYTOLOGY 2000; 197:203-77. [PMID: 10761118 DOI: 10.1016/s0074-7696(00)97005-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Glial cells fulfill important tasks within the neural network of the central and peripheral nervous systems. The synthesis and secretion of various polypeptidic factors (cytokines) and a number of receptors, with which glial cells are equipped, allow them to communicate with their environment. Evidence has accumulated during recent years that neurotrophins play an important role not only for neurons but also for glial cells. This brief update of some morphological, immunocytochemical, and biochemical characteristics of glial cell lineages conveys our present knowledge about glial cells as targets and producers of neurotrophins under normal and pathological conditions. The chapter discusses the presence of neurotrophin receptors on glial cells, glial cells as producers of neurotrophins, signaling pathways downstream Trk and p75NTR, and the significance of neurotrophins and their receptors for glial cells during development, in cell death and survival, and in neurological disorders.
Collapse
Affiliation(s)
- H H Althaus
- AG Neural Regeneration, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | | |
Collapse
|
47
|
Abstract
Neural cell adhesion molecules (CAMs) of the immunoglobulin superfamily nucleate and maintain groups of cells at key sites during early development and in the adult. In addition to their adhesive properties, binding of CAMs can affect intracellular signaling. Their ability to influence developmental events, including cell migration, proliferation, and differentiation can therefore result both from their adhesive as well as their signaling properties. This review focuses on the two CAMs for which the most information is known, the neural CAM, N-CAM, and L1. N-CAM was the first CAM to be characterized and, therefore, has been studied extensively. The binding of N-CAM to cells leads to a number of signaling events, some of which result in changes in gene expression. Interest in L1 derives from the fact that mutations in its gene lead to human genetic diseases including mental retardation. Much is known about modifications of the L1 cytoplasmic domain and its interaction with cytoskeletal molecules. The study of CAM signaling mechanisms has been assay-dependent rather than molecule-dependent, with particular emphasis on assays of neurite outgrowth and gene expression, an emphasis that is maintained throughout the review. The signals generated following CAM binding that lead to alterations in cell morphology and gene expression have been linked directly in only a few cases. We also review information on other CAMs, giving special consideration to those that are anchored in the membrane by a phospholipid anchor. These proteins, including a form of N-CAM, are presumed to be localized in lipid rafts, membrane substructures that include distinctive subsets of cytoplasmic signaling molecules such as members of the src-family of nonreceptor protein tyrosine kinases. In the end, these studies may reveal that what CAMs do after they bind cells together may have as profound consequences for the cells as the adhesive interactions themselves. This area will therefore remain a rich ground for future studies.
Collapse
Affiliation(s)
- K L Crossin
- Department of Neurobiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
| | | |
Collapse
|
48
|
Wang R, St John PL, Kretzler M, Wiggins RC, Abrahamson DR. Molecular cloning, expression, and distribution of glomerular epithelial protein 1 in developing mouse kidney. Kidney Int 2000; 57:1847-59. [PMID: 10792603 DOI: 10.1046/j.1523-1755.2000.00034.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
BACKGROUND Glomerular epithelial protein 1 (GLEPP1) is a receptor-like membrane protein tyrosine phosphatase (RPTP) with a large ectodomain consisting of multiple fibronectin type III repeats, a single transmembrane segment, and a single cytoplasmic phosphatase active site sequence. In adult human and rabbit kidneys, GLEPP1 is found exclusively on apical membranes of podocytes and especially on surfaces of foot processes. Although neither ligand nor function for this protein is known, other RPTPs with similar topologies have been implicated in mediating adherence behavior of cells. METHODS To evaluate potential roles of GLEPP1 further, we cloned the full-length mouse GLEPP1 cDNA and examined its expression patterns in developing kidney by Northern blot analysis, in situ hybridization, and immunofluorescence microscopy. RESULTS Nucleotide sequencing showed that mouse GLEPP1 was approximately 80% identical to rabbit and human GLEPP1 and approximately 91% identical at the amino acid level. The membrane-spanning and phosphatase domains of mouse GLEPP1 shared> 99% homology with PTPphi, a murine macrophage cytoplasmic phosphatase. Northern analysis identified a single GLEPP1 transcript of approximately 5.5 kb in fetal kidney that became approximately threefold more abundant in adults. In situ hybridization of newborn mouse kidney revealed GLEPP1 mRNA in visceral epithelial cells (developing podocytes) of comma- and S-shaped nephric figures, and expression increased in capillary loop and maturing stage glomeruli. Beginning on embryonic day 14, GLEPP1 protein was first observed on cuboidal podocytes of capillary loop stage glomeruli, but nascent podocytes of earlier comma- and S-shaped nephric figures were negative. At later stages of glomerular maturation, where foot process elongation and interdigitation occurs, GLEPP1 immunolabeling intensified on podocytes and then persisted at high levels in fully developed glomeruli. CONCLUSION Our findings are consistent with a role for GLEPP1 in mediating and maintaining podocyte differentiation specifically.
Collapse
Affiliation(s)
- R Wang
- Department of Cell Biology, University of Alabama at Birmingham, USA
| | | | | | | | | |
Collapse
|
49
|
Blanchetot C, den Hertog J. Multiple interactions between receptor protein-tyrosine phosphatase (RPTP) alpha and membrane-distal protein-tyrosine phosphatase domains of various RPTPs. J Biol Chem 2000; 275:12446-52. [PMID: 10777529 DOI: 10.1074/jbc.275.17.12446] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Receptor protein-tyrosine phosphatase (RPTP) alpha belongs to the large family of receptor protein-tyrosine phosphatases containing two tandem phosphatase domains. Most of the catalytic activity is retained in the first, membrane-proximal domain (RPTPalpha-D1), and little is known about the function of the second, membrane-distal domain (RPTPalpha-D2). We investigated whether proteins bound to RPTPalpha using the two-hybrid system and found that the second domain of RPTPsigma interacted with the juxtamembrane domain of RPTPalpha. We confirmed this interaction by co-immunoprecipitation experiments. Furthermore, RPTPalpha not only interacted with RPTPsigma-D2 but also with RPTPalpha-D2, LAR-D2, RPTPdelta-D2, and RPTPmu-D2, members of various RPTP subfamilies, although with different affinities. In the yeast two-hybrid system and in glutathione S-transferase pull-down assays, we show that the RPTP-D2s interacted directly with the wedge structure of RPTPalpha-D1 that has been demonstrated to be involved in inactivation of the RPTPalpha-D1/RPTPalpha-D1 homodimer. The interaction was specific because the equivalent wedge structure in LAR was unable to interact with RPTPalpha-D2 or LAR-D2. In vivo, we show that other interaction sites exist as well, including the C terminus of RPTPalpha-D2. The observation that RPTPalpha, but not LAR, bound to multiple RPTP-D2s with varying affinities suggests a specific mechanism of cross-talk between RPTPs that may regulate their biological function.
Collapse
Affiliation(s)
- C Blanchetot
- Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Uppsalalaan 8, 3584 CT Utrecht, The Netherlands
| | | |
Collapse
|
50
|
Tisi MA, Xie Y, Yeo TT, Longo FM. Downregulation of LAR tyrosine phosphatase prevents apoptosis and augments NGF-induced neurite outgrowth. ACTA ACUST UNITED AC 2000. [DOI: 10.1002/(sici)1097-4695(200003)42:4<477::aid-neu8>3.0.co;2-b] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|