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Suresh S, Shaw AL, Pemberton JG, Scott MK, Harris NJ, Parson MAH, Jenkins ML, Rohilla P, Alejandro-Alvarez-Prats, Balla T, Yip CK, Burke JE. Molecular basis for plasma membrane recruitment of PI4KA by EFR3. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.30.587787. [PMID: 38746453 PMCID: PMC11092606 DOI: 10.1101/2024.04.30.587787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
The lipid kinase phosphatidylinositol 4 kinase III alpha (PI4KIIIα/PI4KA) is a master regulator of the lipid composition and asymmetry of the plasma membrane. PI4KA exists primarily in a heterotrimeric complex with its regulatory proteins TTC7 and FAM126. Fundamental to PI4KA activity is its targeted recruitment to the plasma membrane by the lipidated proteins EFR3A and EFR3B. Here, we report a cryo-EM structure of the C-terminus of EFR3A bound to the PI4KA-TTC7B-FAM126A complex, with extensive validation using both hydrogen deuterium exchange mass spectrometry (HDX-MS), and mutational analysis. The EFR3A C-terminus undergoes a disorder-order transition upon binding to the PI4KA complex, with an unexpected direct interaction with both TTC7B and FAM126A. Complex disrupting mutations in TTC7B, FAM126A, and EFR3 decrease PI4KA recruitment to the plasma membrane. Multiple post-translational modifications and disease linked mutations map to this site, providing insight into how PI4KA membrane recruitment can be regulated and disrupted in human disease.
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Affiliation(s)
- Sushant Suresh
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Alexandria L Shaw
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
- Current address: Department of Biology, Western University, London, ON, N6A 3K7 Canada
| | - Mackenzie K Scott
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Noah J Harris
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Matthew AH Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - Poojah Rohilla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Alejandro-Alvarez-Prats
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Calvin K Yip
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
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Suresh S, Burke JE. Structural basis for the conserved roles of PI4KA and its regulatory partners and their misregulation in disease. Adv Biol Regul 2023; 90:100996. [PMID: 37979461 DOI: 10.1016/j.jbior.2023.100996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 10/17/2023] [Indexed: 11/20/2023]
Abstract
The type III Phosphatidylinositol 4-kinase alpha (PI4KA) is an essential lipid kinase that is a master regulator of phosphoinositide signalling at the plasma membrane (PM). It produces the predominant pool of phosphatidylinositol 4-phosphate (PI4P) at the PM, with this being essential in lipid transport and in regulating the PLC and PI3K signalling pathways. PI4KA is essential and is highly conserved in all eukaryotes. In yeast, the PI4KA ortholog stt4 predominantly exists as a heterodimer with its regulatory partner ypp1. In higher eukaryotes, PI4KA instead primarily forms a heterotrimer with a TTC7 subunit (ortholog of ypp1) and a FAM126 subunit. In all eukaryotes PI4KA is recruited to the plasma membrane by the protein EFR3, which does not directly bind PI4KA, but instead binds to the TTC7/ypp1 regulatory partner. Misregulation in PI4KA or its regulatory partners is involved in myriad human diseases, including loss of function mutations in neurodevelopmental and inflammatory intestinal disorders and gain of function in human cancers. This review describes an in-depth analysis of the structure function of PI4KA and its regulatory partners, with a major focus on comparing and contrasting the differences in regulation of PI4KA throughout evolution.
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Affiliation(s)
- Sushant Suresh
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 2Y2, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 2Y2, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada.
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3
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Govindarajan B, Sbrissa D, Pressprich M, Kim S, Rishi AK, Vaishampayan U, Cher ML, Chinni SR. Adaptor proteins mediate CXCR4 and PI4KA crosstalk in prostate cancer cells and the significance of PI4KA in bone tumor growth. Sci Rep 2023; 13:20634. [PMID: 37996444 PMCID: PMC10667255 DOI: 10.1038/s41598-023-47633-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 11/16/2023] [Indexed: 11/25/2023] Open
Abstract
The chemokine receptor, CXCR4 signaling regulates cell growth, invasion, and metastasis to the bone-marrow niche in prostate cancer (PCa). Previously, we established that CXCR4 interacts with phosphatidylinositol 4-kinase IIIα (PI4KIIIα encoded by PI4KA) through its adaptor proteins and PI4KA overexpressed in the PCa metastasis. To further characterize how the CXCR4-PI4KIIIα axis promotes PCa metastasis, here we identify CXCR4 binds to PI4KIIIα adaptor proteins TTC7 and this interaction induce plasma membrane PI4P production in prostate cancer cells. Inhibiting PI4KIIIα or TTC7 reduces plasma membrane PI4P production, cellular invasion, and bone tumor growth. Using metastatic biopsy sequencing, we found PI4KA expression in tumors correlated with overall survival and contributes to immunosuppressive bone tumor microenvironment through preferentially enriching non-activated and immunosuppressive macrophage populations. Altogether we have characterized the chemokine signaling axis through CXCR4-PI4KIIIα interaction contributing to the growth of prostate cancer bone metastasis.
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Affiliation(s)
- Barani Govindarajan
- Department of Pathology, Wayne State University, School of Medicine, 9245 Scott Hall, 540 E. Canfield Avenue, Detroit, MI, 48201, USA
| | - Diego Sbrissa
- Department of Urology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA
| | - Mark Pressprich
- Department of Urology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA
| | - Seongho Kim
- Department of Oncology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA
- Biostatistics and Bioinformatics Core, Wayne State University, School of Medicine, Detroit, MI, 48201, USA
| | - Arun K Rishi
- Department of Oncology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA
| | - Ulka Vaishampayan
- Department of Oncology, University of Michigan, 7217 Rogel Cancer Center, Ann Arbor, MI, USA
| | - Michael L Cher
- Department of Pathology, Wayne State University, School of Medicine, 9245 Scott Hall, 540 E. Canfield Avenue, Detroit, MI, 48201, USA
- Department of Urology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA
- Department of Oncology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA
| | - Sreenivasa R Chinni
- Department of Pathology, Wayne State University, School of Medicine, 9245 Scott Hall, 540 E. Canfield Avenue, Detroit, MI, 48201, USA.
- Department of Urology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA.
- Department of Oncology, Wayne State University, School of Medicine, Detroit, MI, 48201, USA.
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Trybus M, Hryniewicz-Jankowska A, Wójtowicz K, Trombik T, Czogalla A, Sikorski AF. EFR3A: a new raft domain organizing protein? Cell Mol Biol Lett 2023; 28:86. [PMID: 37880612 PMCID: PMC10601247 DOI: 10.1186/s11658-023-00497-y] [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: 03/12/2023] [Accepted: 10/04/2023] [Indexed: 10/27/2023] Open
Abstract
BACKGROUND Membrane rafts play a crucial role in the regulation of many important biological processes. Our previous data suggest that specific interactions of flotillins with MPP1 are responsible for membrane raft domain organization and regulation in erythroid cells. Interaction of the flotillin-based protein network with specific membrane components underlies the mechanism of raft domain formation and regulation, including in cells with low expression of MPP1. METHODS We sought to identify other flotillin partners via the immobilized recombinant flotillin-2-based affinity approach and mass spectrometry technique. The results were further confirmed via immunoblotting and via co-immunoprecipitation. In order to study the effect of the candidate protein on the physicochemical properties of the plasma membrane, the gene was knocked down via siRNA, and fluorescence lifetime imaging microscopy and spot-variation fluorescence correlation spectroscopy was employed. RESULTS EFR3A was identified as a candidate protein that interacts with flotillin-2. Moreover, this newly discovered interaction was demonstrated via overlay assay using recombinant EFR3A and flotillin-2. EFR3A is a stable component of the detergent-resistant membrane fraction of HeLa cells, and its presence was sensitive to the removal of cholesterol. While silencing the EFR3A gene, we observed decreased order of the plasma membrane of living cells or giant plasma membrane vesicles derived from knocked down cells and altered mobility of the raft probe, as indicated via fluorescence lifetime imaging microscopy and spot-variation fluorescence correlation spectroscopy. Moreover, silencing of EFR3A expression was found to disturb epidermal growth factor receptor and phospholipase C gamma phosphorylation and affect epidermal growth factor-dependent cytosolic Ca2+ concentration. CONCLUSIONS Altogether, our results suggest hitherto unreported flotillin-2-EFR3A interaction, which might be responsible for membrane raft organization and regulation. This implies participation of this interaction in the regulation of multiple cellular processes, including those connected with cell signaling which points to the possible role in human health, in particular human cancer biology.
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Affiliation(s)
- Magdalena Trybus
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Anita Hryniewicz-Jankowska
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Karolina Wójtowicz
- Department of Biotransformation, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Tomasz Trombik
- Chair and Department of Biochemistry and Molecular Biology, Medical University of Lublin, Chodzki 1, 20-093, Lublin, Poland
| | - Aleksander Czogalla
- Department of Cytobiochemistry, Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14a, 50-383, Wroclaw, Poland.
| | - Aleksander F Sikorski
- Research and Development Center, Regional Specialist Hospital, Kamienskiego73a, 51-154, Wroclaw, Poland.
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Barlow-Busch I, Shaw AL, Burke JE. PI4KA and PIKfyve: Essential phosphoinositide signaling enzymes involved in myriad human diseases. Curr Opin Cell Biol 2023; 83:102207. [PMID: 37453227 DOI: 10.1016/j.ceb.2023.102207] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/09/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
Lipid phosphoinositides are master regulators of multiple cellular functions. Misregulation of the activity of the lipid kinases that generate phosphoinositides is causative of human diseases, including cancer, neurodegeneration, developmental disorders, immunodeficiencies, and inflammatory disease. This review will present a summary of recent discoveries on the roles of two phosphoinositide kinases (PI4KA and PIKfyve), which have emerged as targets for therapeutic intervention. Phosphatidylinositol 4-kinase alpha (PI4KA) generates PI4P at the plasma membrane and PIKfyve generates PI(3,5)P2 at endo-lysosomal membranes. Both of these enzymes exist as multi-protein mega complexes that are under myriad levels of regulation. Human disease can be caused by either loss or gain-of-function of these complexes, so understanding how they are regulated will be essential in the design of therapeutics. We will summarize insight into how these enzymes are regulated by their protein-binding partners, with a major focus on the unanswered questions of how their activity is controlled.
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Affiliation(s)
- Isobel Barlow-Busch
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Alexandria L Shaw
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada; Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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6
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Hoellerbauer P, Biery MC, Arora S, Rao Y, Girard EJ, Mitchell K, Dighe P, Kufeld M, Kuppers DA, Herman JA, Holland EC, Soroceanu L, Vitanza NA, Olson JM, Pritchard JR, Paddison PJ. Functional genomic analysis of adult and pediatric brain tumor isolates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.05.522885. [PMID: 36711964 PMCID: PMC9881972 DOI: 10.1101/2023.01.05.522885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background Adult and pediatric tumors display stark differences in their mutation spectra and chromosome alterations. Here, we attempted to identify common and unique gene dependencies and their associated biomarkers among adult and pediatric tumor isolates using functional genetic lethal screens and computational modeling. Methods We performed CRISRP-Cas9 lethality screens in two adult glioblastoma (GBM) tumor isolates and five pediatric brain tumor isolates representing atypical teratoid rhabdoid tumors (ATRT), diffuse intrinsic pontine glioma, GBM, and medulloblastoma. We then integrated the screen results with machine learning-based gene-dependency models generated from data from >900 cancer cell lines. Results We found that >50% of candidate dependencies of 280 identified were shared between adult GBM tumors and individual pediatric tumor isolates. 68% of screen hits were found as nodes in our network models, along with shared and tumor-specific predictors of gene dependencies. We investigated network predictors associated with ADAR, EFR3A, FGFR1 (pediatric-specific), and SMARCC2 (ATRT-specific) gene dependency among our tumor isolates. Conclusions The results suggest that, despite harboring disparate genomic signatures, adult and pediatric tumor isolates share a preponderance of genetic dependences. Further, combining data from primary brain tumor lethality screens with large cancer cell line datasets produced valuable insights into biomarkers of gene dependency, even for rare cancers. Importance of the Study Our results demonstrate that large cancer cell lines data sets can be computationally mined to identify known and novel gene dependency relationships in adult and pediatric human brain tumor isolates. Gene dependency networks and lethality screen results represent a key resource for neuro-oncology and cancer research communities. We also highlight some of the challenges and limitations of this approach.
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Affiliation(s)
- Pia Hoellerbauer
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA USA
| | - Matt C Biery
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA USA
- Ben Towne Center for Childhood Cancer Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Sonali Arora
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA USA
| | - Yiyun Rao
- Huck Institute for the Life Sciences, Pennsylvania State University, State College, PA, USA
| | - Emily J Girard
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA USA
| | - Kelly Mitchell
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA USA
| | - Pratiksha Dighe
- California Pacific Medical Center Research Institute, San Francisco, CA 94107, USA
| | - Megan Kufeld
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA USA
| | - Daniel A Kuppers
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA USA
| | - Jacob A Herman
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA USA
| | - Eric C Holland
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA USA
| | - Liliana Soroceanu
- California Pacific Medical Center Research Institute, San Francisco, CA 94107, USA
| | - Nicholas A Vitanza
- Ben Towne Center for Childhood Cancer Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - James M Olson
- Clinical Research Division, Fred Hutchinson Cancer Center, Seattle, WA USA
- Ben Towne Center for Childhood Cancer Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Justin R Pritchard
- Huck Institute for the Life Sciences, Pennsylvania State University, State College, PA, USA
| | - Patrick J Paddison
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA USA
- Molecular and Cellular Biology Program, University of Washington, Seattle, WA USA
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Zhang K, Kang L, Zhang H, Bai L, Pang H, Liu Q, Zhang X, Chen D, Yu H, Lv Y, Gao M, Liu Y, Gai Z, Wang D, Li X. A synonymous mutation in PI4KA impacts the transcription and translation process of gene expression. Front Immunol 2022; 13:987666. [DOI: 10.3389/fimmu.2022.987666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022] Open
Abstract
Phosphatidylinositol-4-kinase alpha (PI4KIIIα), encoded by the PI4KA gene, can synthesize phosphatidylinositol-4-phosphate (PI-4-P), which serves as a specific membrane marker and is instrumental in signal transduction. PI4KA mutations can cause autosomal recessive diseases involving neurological, intestinal, and immunological conditions (OMIM:619621, 616531, 619708). We detected sepsis, severe diarrhea, and decreased immunoglobulin levels in one neonate. Two novel compound heterozygous mutations, c.5846T>C (p.Leu1949Pro) and c.3453C>T (p.Gly1151=), were identified in the neonate from the father and the mother, respectively. Sanger sequencing and reverse transcription polymerase chain reaction (RT-PCR) for peripheral blood and minigene splicing assays showed a deletion of five bases (GTGAG) with the c.3453C>T variant at the mRNA level, which could result in a truncated protein (p.Gly1151GlyfsTer17). The missense mutation c.5846T>C (p.Leu1949Pro) kinase activity was measured, and little or no catalytic activity was detected. According to the clinical characteristics and gene mutations with functional verification, our pediatricians diagnosed the child with a combined immunodeficiency and intestinal disorder close to gastrointestinal defects and immunodeficiency syndrome 2 (GIDID2; OMIM: 619708). Medicines such as immunomodulators are prescribed to balance immune dysregulation. This study is the first report of a synonymous mutation in the PI4KA gene that influences alternative splicing. Our findings expand the mutation spectrum leading to PI4KIIIa deficiency-related diseases and provide exact information for genetic counseling.
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Habib K, Bishayee K, Kang J, Sadra A, Huh SO. RNA Binding Protein Rbms1 Enables Neuronal Differentiation and Radial Migration during Neocortical Development by Binding and Stabilizing the RNA Message for Efr3a. Mol Cells 2022; 45:588-602. [PMID: 35754370 PMCID: PMC9385565 DOI: 10.14348/molcells.2022.0044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/06/2022] [Accepted: 04/09/2022] [Indexed: 11/27/2022] Open
Abstract
Various RNA-binding proteins (RBPs) are key components in RNA metabolism and contribute to several neurodevelop-mental disorders. To date, only a few of such RBPs have been characterized for their roles in neocortex development. Here, we show that the RBP, Rbms1, is required for radial migration, polarization and differentiation of neuronal progenitors to neurons in the neocortex development. Rbms1 expression is highest in the early development in the developing cortex, with its expression gradually diminishing from embryonic day 13.5 (E13.5) to postnatal day 0 (P0). From in utero electroporation (IUE) experiments when Rbms1 levels are knocked down in neuronal progenitors, their transition from multipolar to bipolar state is delayed and this is accompanied by a delay in radial migration of these cells. Reduced Rbms1 levels in vivo also reduces differentiation as evidenced by a decrease in levels of several differentiation markers, meanwhile having no significant effects on proliferation and cell cycle rates of these cells. As an RNA binding protein, we profiled the RNA binders of Rbms1 by a cross-linked-RIP sequencing assay, followed by quantitative real-time polymerase chain reaction verification and showed that Rbms1 binds and stabilizes the mRNA for Efr3a, a signaling adapter protein. We also demonstrate that ectopic Efr3a can recover the cells from the migration defects due to loss of Rbms1, both in vivo and in vitro migration assays with cultured cells. These imply that one of the functions of Rbms1 involves the stabilization of Efr3a RNA message, required for migration and maturation of neuronal progenitors in radial migration in the developing neocortex.
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Affiliation(s)
- Khadija Habib
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chuncheon 24252, Korea
| | - Kausik Bishayee
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chuncheon 24252, Korea
| | - Jieun Kang
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chuncheon 24252, Korea
| | - Ali Sadra
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chuncheon 24252, Korea
| | - Sung-Oh Huh
- Department of Pharmacology, College of Medicine, Institute of Natural Medicine, Hallym University, Chuncheon 24252, Korea
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9
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Batrouni AG, Bag N, Phan HT, Baird BA, Baskin JM. A palmitoylation code controls PI4KIIIα complex formation and PI(4,5)P2 homeostasis at the plasma membrane. J Cell Sci 2022; 135:272297. [PMID: 34569608 DOI: 10.1242/jcs.259365] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022] Open
Abstract
Phosphatidylinositol 4-kinase IIIα (PI4KIIIα) is the major enzyme responsible for generating phosphatidylinositol (4)-phosphate [PI(4)P] at the plasma membrane. This lipid kinase forms two multicomponent complexes, both including a palmitoylated anchor, EFR3. Whereas both PI4KIIIα complexes support production of PI(4)P, the distinct functions of each complex and mechanisms underlying the interplay between them remain unknown. Here, we present roles for differential palmitoylation patterns within a tri-cysteine motif in EFR3B (Cys5, Cys7 and Cys8) in controlling the distribution of PI4KIIIα between these two complexes at the plasma membrane and corresponding functions in phosphoinositide homeostasis. Spacing of palmitoyl groups within three doubly palmitoylated EFR3B 'lipoforms' affects both interactions between EFR3B and TMEM150A, a transmembrane protein governing formation of a PI4KIIIα complex functioning in rapid phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] resynthesis following phospholipase C signaling, and EFR3B partitioning within liquid-ordered and -disordered regions of the plasma membrane. This work identifies a palmitoylation code involved in controlling protein-protein and protein-lipid interactions that affect a plasma membrane-resident lipid biosynthetic pathway.
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Affiliation(s)
- Alex G Batrouni
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.,Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA
| | - Nirmalya Bag
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Henry T Phan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Barbara A Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jeremy M Baskin
- Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
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Components of the phosphatidylserine endoplasmic reticulum to plasma membrane transport mechanism as targets for KRAS inhibition in pancreatic cancer. Proc Natl Acad Sci U S A 2021; 118:2114126118. [PMID: 34903667 DOI: 10.1073/pnas.2114126118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2021] [Indexed: 12/19/2022] Open
Abstract
KRAS is mutated in 90% of human pancreatic ductal adenocarcinomas (PDACs). To function, KRAS must localize to the plasma membrane (PM) via a C-terminal membrane anchor that specifically engages phosphatidylserine (PtdSer). This anchor-binding specificity renders KRAS-PM localization and signaling capacity critically dependent on PM PtdSer content. We now show that the PtdSer lipid transport proteins, ORP5 and ORP8, which are essential for maintaining PM PtdSer levels and hence KRAS PM localization, are required for KRAS oncogenesis. Knockdown of either protein, separately or simultaneously, abrogated growth of KRAS-mutant but not KRAS-wild-type pancreatic cancer cell xenografts. ORP5 or ORP8 knockout also abrogated tumor growth in an immune-competent orthotopic pancreatic cancer mouse model. Analysis of human datasets revealed that all components of this PtdSer transport mechanism, including the PM-localized EFR3A-PI4KIIIα complex that generates phosphatidylinositol-4-phosphate (PI4P), and endoplasmic reticulum (ER)-localized SAC1 phosphatase that hydrolyzes counter transported PI4P, are significantly up-regulated in pancreatic tumors compared to normal tissue. Taken together, these results support targeting PI4KIIIα in KRAS-mutant cancers to deplete the PM-to-ER PI4P gradient, reducing PM PtdSer content. We therefore repurposed the US Food and Drug Administration-approved hepatitis C antiviral agent, simeprevir, as a PI4KIIIα inhibitor In a PDAC setting. Simeprevir potently mislocalized KRAS from the PM, reduced the clonogenic potential of pancreatic cancer cell lines in vitro, and abrogated the growth of KRAS-dependent tumors in vivo with enhanced efficacy when combined with MAPK and PI3K inhibitors. We conclude that the cellular ER-to-PM PtdSer transport mechanism is essential for KRAS PM localization and oncogenesis and is accessible to therapeutic intervention.
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11
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Ulengin-Talkish I, Parson MAH, Jenkins ML, Roy J, Shih AZL, St-Denis N, Gulyas G, Balla T, Gingras AC, Várnai P, Conibear E, Burke JE, Cyert MS. Palmitoylation targets the calcineurin phosphatase to the phosphatidylinositol 4-kinase complex at the plasma membrane. Nat Commun 2021; 12:6064. [PMID: 34663815 PMCID: PMC8523714 DOI: 10.1038/s41467-021-26326-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/29/2021] [Indexed: 11/25/2022] Open
Abstract
Calcineurin, the conserved protein phosphatase and target of immunosuppressants, is a critical mediator of Ca2+ signaling. Here, to discover calcineurin-regulated processes we examined an understudied isoform, CNAβ1. We show that unlike canonical cytosolic calcineurin, CNAβ1 localizes to the plasma membrane and Golgi due to palmitoylation of its divergent C-terminal tail, which is reversed by the ABHD17A depalmitoylase. Palmitoylation targets CNAβ1 to a distinct set of membrane-associated interactors including the phosphatidylinositol 4-kinase (PI4KA) complex containing EFR3B, PI4KA, TTC7B and FAM126A. Hydrogen-deuterium exchange reveals multiple calcineurin-PI4KA complex contacts, including a calcineurin-binding peptide motif in the disordered tail of FAM126A, which we establish as a calcineurin substrate. Calcineurin inhibitors decrease PI4P production during Gq-coupled GPCR signaling, suggesting that calcineurin dephosphorylates and promotes PI4KA complex activity. In sum, this work discovers a calcineurin-regulated signaling pathway which highlights the PI4KA complex as a regulatory target and reveals that dynamic palmitoylation confers unique localization, substrate specificity and regulation to CNAβ1.
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Affiliation(s)
| | - Matthew A H Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Jagoree Roy
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Alexis Z L Shih
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Nicole St-Denis
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, University of Toronto, Toronto, Canada
- High-Fidelity Science Communications, Summerside, PE, Canada
| | - Gergo Gulyas
- Section on Molecular Signal Transduction, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, University of Toronto, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Péter Várnai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Elizabeth Conibear
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
- Department of Biochemistry, The University of British Columbia, Vancouver, BC, Canada
| | - Martha S Cyert
- Department of Biology, Stanford University, Stanford, CA, USA.
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12
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Oncogenic KRAS is dependent upon an EFR3A-PI4KA signaling axis for potent tumorigenic activity. Nat Commun 2021; 12:5248. [PMID: 34504076 PMCID: PMC8429657 DOI: 10.1038/s41467-021-25523-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/10/2021] [Indexed: 11/15/2022] Open
Abstract
The HRAS, NRAS, and KRAS genes are collectively mutated in a fifth of all human cancers. These mutations render RAS GTP-bound and active, constitutively binding effector proteins to promote signaling conducive to tumorigenic growth. To further elucidate how RAS oncoproteins signal, we mined RAS interactomes for potential vulnerabilities. Here we identify EFR3A, an adapter protein for the phosphatidylinositol kinase PI4KA, to preferentially bind oncogenic KRAS. Disrupting EFR3A or PI4KA reduces phosphatidylinositol-4-phosphate, phosphatidylserine, and KRAS levels at the plasma membrane, as well as oncogenic signaling and tumorigenesis, phenotypes rescued by tethering PI4KA to the plasma membrane. Finally, we show that a selective PI4KA inhibitor augments the antineoplastic activity of the KRASG12C inhibitor sotorasib, suggesting a clinical path to exploit this pathway. In sum, we have discovered a distinct KRAS signaling axis with actionable therapeutic potential for the treatment of KRAS-mutant cancers. The lipid composition of the plasma membrane defines the localisation of KRAS and its oncogenic function. Here the authors show that EFR3A binds to active KRAS to recruit PI4KA and alters the lipid composition of the plasma membrane to promote KRAS oncogenic signalling and tumorigenesis.
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13
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Myeong J, de la Cruz L, Jung SR, Yeon JH, Suh BC, Koh DS, Hille B. Phosphatidylinositol 4,5-bisphosphate is regenerated by speeding of the PI 4-kinase pathway during long PLC activation. J Gen Physiol 2021; 152:211533. [PMID: 33186442 PMCID: PMC7671494 DOI: 10.1085/jgp.202012627] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 10/13/2020] [Indexed: 01/05/2023] Open
Abstract
The dynamic metabolism of membrane phosphoinositide lipids involves several cellular compartments including the ER, Golgi, and plasma membrane. There are cycles of phosphorylation and dephosphorylation and of synthesis, transfer, and breakdown. The simplified phosphoinositide cycle comprises synthesis of phosphatidylinositol in the ER, transport, and phosphorylation in the Golgi and plasma membranes to generate phosphatidylinositol 4,5-bisphosphate, followed by receptor-stimulated hydrolysis in the plasma membrane and return of the components to the ER for reassembly. Using probes for specific lipid species, we have followed and analyzed the kinetics of several of these events during stimulation of M1 muscarinic receptors coupled to the G-protein Gq. We show that during long continued agonist action, polyphosphorylated inositol lipids are initially depleted but then regenerate while agonist is still present. Experiments and kinetic modeling reveal that the regeneration results from gradual but massive up-regulation of PI 4-kinase pathways rather than from desensitization of receptors. Golgi pools of phosphatidylinositol 4-phosphate and the lipid kinase PI4KIIIα (PI4KA) contribute to this homeostatic regeneration. This powerful acceleration, which may be at the level of enzyme activity or of precursor and product delivery, reveals strong regulatory controls in the phosphoinositide cycle.
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Affiliation(s)
- Jongyun Myeong
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA
| | - Lizbeth de la Cruz
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA
| | | | - Jun-Hee Yeon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Byung-Chang Suh
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Duk-Su Koh
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA
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14
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Nakatsu F, Kawasaki A. Functions of Oxysterol-Binding Proteins at Membrane Contact Sites and Their Control by Phosphoinositide Metabolism. Front Cell Dev Biol 2021; 9:664788. [PMID: 34249917 PMCID: PMC8264513 DOI: 10.3389/fcell.2021.664788] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 05/06/2021] [Indexed: 01/10/2023] Open
Abstract
Lipids must be correctly transported within the cell to the right place at the right time in order to be fully functional. Non-vesicular lipid transport is mediated by so-called lipid transfer proteins (LTPs), which contain a hydrophobic cavity that sequesters lipid molecules. Oxysterol-binding protein (OSBP)-related proteins (ORPs) are a family of LTPs known to harbor lipid ligands, such as cholesterol and phospholipids. ORPs act as a sensor or transporter of those lipid ligands at membrane contact sites (MCSs) where two different cellular membranes are closely apposed. In particular, a characteristic functional property of ORPs is their role as a lipid exchanger. ORPs mediate counter-directional transport of two different lipid ligands at MCSs. Several, but not all, ORPs transport their lipid ligand from the endoplasmic reticulum (ER) in exchange for phosphatidylinositol 4-phosphate (PI4P), the other ligand, on apposed membranes. This ORP-mediated lipid “countertransport” is driven by the concentration gradient of PI4P between membranes, which is generated by its kinases and phosphatases. In this review, we will discuss how ORP function is tightly coupled to metabolism of phosphoinositides such as PI4P. Recent progress on the role of ORP-mediated lipid transport/countertransport at multiple MCSs in cellular functions will be also discussed.
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Affiliation(s)
- Fubito Nakatsu
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
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15
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Batrouni AG, Baskin JM. The chemistry and biology of phosphatidylinositol 4-phosphate at the plasma membrane. Bioorg Med Chem 2021; 40:116190. [PMID: 33965837 DOI: 10.1016/j.bmc.2021.116190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 12/29/2022]
Abstract
Phosphoinositides are an important class of anionic, low abundance signaling lipids distributed throughout intracellular membranes. The plasma membrane contains three phosphoinositides: PI(4)P, PI(4,5)P2, and PI(3,4,5)P3. Of these, PI(4)P has remained the most mysterious, despite its characterization in this membrane more than a half-century ago. Fortunately, recent methodological innovations at the chemistry-biology interface have spurred a renaissance of interest in PI(4)P. Here, we describe these new toolsets and how they have revealed novel functions for the plasma membrane PI(4)P pool. We examine high-resolution structural characterization of the plasma membrane PI 4-kinase complex that produces PI(4)P, tools for modulating PI(4)P levels including isoform-selective PI 4-kinase inhibitors, and fluorescent probes for visualizing PI(4)P. Collectively, these chemical and biochemical approaches have revealed insights into how cells regulate synthesis of PI(4)P and its downstream metabolites as well as new roles for plasma membrane PI(4)P in non-vesicular lipid transport, membrane homeostasis and trafficking, and cell signaling pathways.
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Affiliation(s)
- Alex G Batrouni
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jeremy M Baskin
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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16
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Pemberton JG, Kim YJ, Balla T. Integrated regulation of the phosphatidylinositol cycle and phosphoinositide-driven lipid transport at ER-PM contact sites. Traffic 2019; 21:200-219. [PMID: 31650663 DOI: 10.1111/tra.12709] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/02/2019] [Accepted: 10/16/2019] [Indexed: 12/20/2022]
Abstract
Among the structural phospholipids that form the bulk of eukaryotic cell membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the common precursor for low-abundance regulatory lipids, collectively referred to as polyphosphoinositides (PPIn). The metabolic turnover of PPIn species has received immense attention because of the essential functions of these lipids as universal regulators of membrane biology and their dysregulation in numerous human pathologies. The diverse functions of PPIn lipids occur, in part, by orchestrating the spatial organization and conformational dynamics of peripheral or integral membrane proteins within defined subcellular compartments. The emerging role of stable contact sites between adjacent membranes as specialized platforms for the coordinate control of ion exchange, cytoskeletal dynamics, and lipid transport has also revealed important new roles for PPIn species. In this review, we highlight the importance of membrane contact sites formed between the endoplasmic reticulum (ER) and plasma membrane (PM) for the integrated regulation of PPIn metabolism within the PM. Special emphasis will be placed on non-vesicular lipid transport during control of the PtdIns biosynthetic cycle as well as toward balancing the turnover of the signaling PPIn species that define PM identity.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Maryland
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Maryland
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Maryland
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17
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Mishra NK, Southekal S, Guda C. Survival Analysis of Multi-Omics Data Identifies Potential Prognostic Markers of Pancreatic Ductal Adenocarcinoma. Front Genet 2019; 10:624. [PMID: 31379917 PMCID: PMC6659773 DOI: 10.3389/fgene.2019.00624] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Accepted: 06/14/2019] [Indexed: 12/12/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is the most common and among the deadliest of pancreatic cancers. Its 5-year survival is only ∼8%. Pancreatic cancers are a heterogeneous group of diseases, of which PDAC is particularly aggressive. Like many other cancers, PDAC also starts as a pre-invasive precursor lesion (known as pancreatic intraepithelial neoplasia, PanIN), which offers an opportunity for both early detection and early treatment. Even advanced PDAC can benefit from prognostic biomarkers. However, reliable biomarkers for early diagnosis or those for prognosis of therapy remain an unfulfilled goal for PDAC. In this study, we selected 153 PDAC patients from the TCGA database and used their clinical, DNA methylation, gene expression, and micro-RNA (miRNA) and long non-coding RNA (lncRNA) expression data for multi-omics analysis. Differential methylations at about 12,000 CpG sites were observed in PDAC tumor genomes, with about 61% of them hypermethylated, predominantly in the promoter regions and in CpG-islands. We correlated promoter methylation and gene expression for mRNAs and identified 17 genes that were previously recognized as PDAC biomarkers. Similarly, several genes (B3GNT3, DMBT1, DEPDC1B) and lncRNAs (PVT1, and GATA6-AS) are strongly correlated with survival, which have not been reported in PDAC before. Other genes such as EFR3B, whose biological roles are not well known in mammals are also found to strongly associated with survival. We further identified 406 promoter methylation target loci associated with patients survival, including known esophageal squamous cell carcinoma biomarkers, cg03234186 (ZNF154), and cg02587316, cg18630667, and cg05020604 (ZNF382). Overall, this is one of the first studies that identified survival associated genes using multi-omics data from PDAC patients.
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Affiliation(s)
- Nitish Kumar Mishra
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| | - Siddesh Southekal
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
| | - Chittibabu Guda
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, United States
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18
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Amyloid β oligomers suppress excitatory transmitter release via presynaptic depletion of phosphatidylinositol-4,5-bisphosphate. Nat Commun 2019; 10:1193. [PMID: 30867420 PMCID: PMC6416269 DOI: 10.1038/s41467-019-09114-z] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 02/21/2019] [Indexed: 12/21/2022] Open
Abstract
Amyloid β (Aβ) oligomer-induced aberrant neurotransmitter release is proposed to be a crucial early event leading to synapse dysfunction in Alzheimer's disease (AD). In the present study, we report that the release probability (Pr) at the synapse between the Schaffer collateral (SC) and CA1 pyramidal neurons is significantly reduced at an early stage in mouse models of AD with elevated Aβ production. High nanomolar synthetic oligomeric Aβ42 also suppresses Pr at the SC-CA1 synapse in wild-type mice. This Aβ-induced suppression of Pr is mainly due to an mGluR5-mediated depletion of phosphatidylinositol-4,5-bisphosphate (PIP2) in axons. Selectively inhibiting Aβ-induced PIP2 hydrolysis in the CA3 region of the hippocampus strongly prevents oligomeric Aβ-induced suppression of Pr at the SC-CA1 synapse and rescues synaptic and spatial learning and memory deficits in APP/PS1 mice. These results first reveal the presynaptic mGluR5-PIP2 pathway whereby oligomeric Aβ induces early synaptic deficits in AD.
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19
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Sengupta N, Jović M, Barnaeva E, Kim DW, Hu X, Southall N, Dejmek M, Mejdrova I, Nencka R, Baumlova A, Chalupska D, Boura E, Ferrer M, Marugan J, Balla T. A large scale high-throughput screen identifies chemical inhibitors of phosphatidylinositol 4-kinase type II alpha. J Lipid Res 2019; 60:683-693. [PMID: 30626625 DOI: 10.1194/jlr.d090159] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/08/2019] [Indexed: 12/24/2022] Open
Abstract
The minor phospholipid, phosphatidylinositol 4-phosphate (PI4P), is emerging as a key regulator of lipid transfer in ER-membrane contact sites. Four different phosphatidylinositol 4-kinase (PI4K) enzymes generate PI4P in different membrane compartments supporting distinct cellular processes, many of which are crucial for the maintenance of cellular integrity but also hijacked by intracellular pathogens. While type III PI4Ks have been targeted by small molecular inhibitors, thus helping decipher their importance in cellular physiology, no inhibitors are available for the type II PI4Ks, which hinders investigations into their cellular functions. Here, we describe the identification of small molecular inhibitors of PI4K type II alpha (PI4K2A) by implementing a large scale small molecule high-throughput screening. A novel assay was developed that allows testing of selected inhibitors against PI4K2A in intact cells using a bioluminescence resonance energy transfer approach adapted to plate readers. The compounds disclosed here will pave the way to the optimization of PI4K2A inhibitors that can be used in cellular and animal studies to better understand the role of this enzyme in both normal and pathological states.
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Affiliation(s)
- Nivedita Sengupta
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Marko Jović
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Elena Barnaeva
- Division of Preclinical Innovation National Center for Advancing Translational Sciences, Rockville, MD 20850
| | - David W Kim
- Division of Preclinical Innovation National Center for Advancing Translational Sciences, Rockville, MD 20850
| | - Xin Hu
- Division of Preclinical Innovation National Center for Advancing Translational Sciences, Rockville, MD 20850
| | - Noel Southall
- Division of Preclinical Innovation National Center for Advancing Translational Sciences, Rockville, MD 20850
| | - Milan Dejmek
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic
| | - Ivana Mejdrova
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic
| | - Radim Nencka
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic
| | - Adriana Baumlova
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic
| | - Dominika Chalupska
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic, 166 10 Prague 6, Czech Republic
| | - Marc Ferrer
- Division of Preclinical Innovation National Center for Advancing Translational Sciences, Rockville, MD 20850
| | - Juan Marugan
- Division of Preclinical Innovation National Center for Advancing Translational Sciences, Rockville, MD 20850
| | - Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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20
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A novel cross-talk between CXCR4 and PI4KIIIα in prostate cancer cells. Oncogene 2018; 38:332-344. [PMID: 30111818 PMCID: PMC6336684 DOI: 10.1038/s41388-018-0448-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/03/2018] [Accepted: 07/14/2018] [Indexed: 12/20/2022]
Abstract
Chemokine signaling regulates cell migration and tumor metastasis. CXCL12, a member of the chemokine family, and its receptor, CXCR4, a G protein coupled receptor (GPCR), are key mediators of prostate-cancer (PC) bone metastasis. In PC cells androgens activate CXCR4 gene expression and receptor signaling on lipid rafts, which induces protease expression and cancer cell invasion. To identify novel lipid-raft-associated CXCR4 regulators supporting invasion/metastasis, we performed a SILAC-based quantitative proteomic analysis of lipid-rafts derived from PC3 stable cell lines with overexpression or knockdown of CXCR4. This analysis identified the evolutionarily conserved phosphatidylinositol 4-kinase IIIα (PI4KIIIα), and SAC1 phosphatase that dephosphorylates phosphatidylinositol-4-phosphate as potential candidate CXCR4 regulators. CXCR4 interacted with PI4KIIIα membrane targeting machinery recruiting them to the plasma membrane for PI4P production. Consistent with this interaction, PI4KIIIα was found tightly linked to the CXCR4 induced PC cell invasion. Thus, ablation of PI4KIIIα in CXCR4-expressing PC3 cells reduced cellular invasion in response to a variety of chemokines. Immunofluorescence microscopy in CXCR4 expressing cells revealed localized production of PI4P on the invasive projections. Human tumor studies documented increased PI4KIIIα expression in metastatic tumors vs. the primary tumor counterparts, further supporting the PI4KIIIα role in tumor metastasis. Furthermore, we also identified an unexpected function of PI4KIIIα in GPCR signaling where CXCR4 regulates PI4KIIIα activity and mediate tumor metastasis. Together, our study identifies a novel cross-talk between PI4KIIIα and CXCR4 in promoting tumor metastasis and suggests that PI4KIIIα pharmacological targeting may have therapeutic benefit for advanced prostate cancer patients.
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21
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Balakrishnan SS, Basu U, Shinde D, Thakur R, Jaiswal M, Raghu P. Regulation of PI4P levels by PI4KIIIα during G-protein-coupled PLC signaling in Drosophila photoreceptors. J Cell Sci 2018; 131:jcs.217257. [PMID: 29980590 DOI: 10.1242/jcs.217257] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/27/2018] [Indexed: 12/27/2022] Open
Abstract
The activation of phospholipase C (PLC) is a conserved mechanism of receptor-activated cell signaling at the plasma membrane. PLC hydrolyzes the minor membrane lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], and continued signaling requires the resynthesis and availability of PI(4,5)P2 at the plasma membrane. PI(4,5)P2 is synthesized by the phosphorylation of phosphatidylinositol 4-phosphate (PI4P). Thus, a continuous supply of PI4P is essential to support ongoing PLC signaling. While the enzyme PI4KA has been identified as performing this function in cultured mammalian cells, its function in the context of an in vivo physiological model has not been established. In this study, we show that, in Drosophila photoreceptors, PI4KIIIα activity is required to support signaling during G-protein-coupled PLC activation. Depletion of PI4KIIIα results in impaired electrical responses to light, and reduced plasma membrane levels of PI4P and PI(4,5)P2 Depletion of the conserved proteins Efr3 and TTC7 [also known as StmA and L(2)k14710, respectively, in flies], which assemble PI4KIIIα at the plasma membrane, also results in an impaired light response and reduced plasma membrane PI4P and PI(4,5)P2 levels. Thus, PI4KIIIα activity at the plasma membrane generates PI4P and supports PI(4,5)P2 levels during receptor activated PLC signaling.
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Affiliation(s)
- Sruthi S Balakrishnan
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Urbashi Basu
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Dhananjay Shinde
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Rajan Thakur
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Manish Jaiswal
- TIFR Center for Interdisciplinary Science, Hyderabad 500107, India
| | - Padinjat Raghu
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore 560065, India
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22
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Videlock EJ, Mahurkar-Joshi S, Hoffman JM, Iliopoulos D, Pothoulakis C, Mayer EA, Chang L. Sigmoid colon mucosal gene expression supports alterations of neuronal signaling in irritable bowel syndrome with constipation. Am J Physiol Gastrointest Liver Physiol 2018; 315:G140-G157. [PMID: 29565640 PMCID: PMC6109711 DOI: 10.1152/ajpgi.00288.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 03/01/2018] [Accepted: 03/05/2018] [Indexed: 01/31/2023]
Abstract
Peripheral factors likely play a role in at least a subset of irritable bowel syndrome (IBS) patients. Few studies have investigated mucosal gene expression using an unbiased approach. Here, we performed mucosal gene profiling in a sex-balanced sample to identify relevant signaling pathways and gene networks and compare with publicly available profiling data from additional cohorts. Twenty Rome III+ IBS patients [10 IBS with constipation (IBS-C), 10 IBS with diarrhea (IBS-D), 5 men/women each), and 10 age-/sex-matched healthy controls (HCs)] underwent sigmoidoscopy with biopsy for gene microarray analysis, including differential expression, weighted gene coexpression network analysis (WGCNA), gene set enrichment analysis, and comparison with publicly available data. Expression levels of 67 genes were validated in an expanded cohort, including the above samples and 18 additional participants (6 each of IBS-C, IBS-D, HCs) using NanoString nCounter technology. There were 1,270 differentially expressed genes (FDR < 0.05) in IBS-C vs. HCs but none in IBS or IBS-D vs. HCs. WGNCA analysis identified activation of the cAMP/protein kinase A signaling pathway. Nine of 67 genes were validated by the NanoString nCounter technology (FDR < 0.05) in the expanded sample. Comparison with publicly available microarray data from the Mayo Clinic and University of Nottingham supports the reproducibility of 17 genes from the microarray analysis and three of nine genes validated by nCounter in IBS-C vs. HCs. This study supports the involvement of peripheral mechanisms in IBS-C, particularly pathways mediating neuronal signaling. NEW & NOTEWORTHY Peripheral factors play a role in the pathophysiology of irritable bowel syndrome (IBS), which, to date, has been mostly evident in IBS with diarrhea. Here, we show that sigmoid colon mucosal gene expression profiles differentiate IBS with constipation from healthy controls. These profiling data and analysis of additional cohorts also support the concept that peripheral neuronal pathways contribute to IBS pathophysiology.
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Affiliation(s)
- Elizabeth J Videlock
- G. Oppenheimer Center for Neurobiology of Stress and Resilience, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California , Los Angeles, California
| | - Swapna Mahurkar-Joshi
- G. Oppenheimer Center for Neurobiology of Stress and Resilience, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California , Los Angeles, California
| | - Jill M Hoffman
- Inflammatory Bowel Disease Research Center, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California , Los Angeles, California
| | - Dimitrios Iliopoulos
- Center for Systems Biomedicine, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California , Los Angeles, California
| | - Charalabos Pothoulakis
- Inflammatory Bowel Disease Research Center, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California , Los Angeles, California
| | - Emeran A Mayer
- G. Oppenheimer Center for Neurobiology of Stress and Resilience, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California , Los Angeles, California
| | - Lin Chang
- G. Oppenheimer Center for Neurobiology of Stress and Resilience, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California , Los Angeles, California
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23
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Hu H, Ye B, Zhang L, Wang Q, Liu Z, Ji S, Liu Q, Lv J, Ma Y, Xu Y, Wu H, Huang F, Xiang M. Efr3a Insufficiency Attenuates the Degeneration of Spiral Ganglion Neurons after Hair Cell Loss. Front Mol Neurosci 2017; 10:86. [PMID: 28424585 PMCID: PMC5372784 DOI: 10.3389/fnmol.2017.00086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 03/10/2017] [Indexed: 01/19/2023] Open
Abstract
Sensorineural hearing loss (SNHL) is caused by an irreversible impairment of cochlear hair cells and subsequent progressive degeneration of spiral ganglion neurons (SGNs). Eighty-five requiring 3 (Efr3) is a plasma membrane protein conserved from yeast to human, and knockout of Efr3a was reported to facilitate the survival of hippocampal newborn neurons in adult mice. Previously, we found Efr3a expression in the auditory neural pathway is upregulated soon after the destruction of hair cells. Here we conducted a time-course analysis of drug-caused damage to hearing ability, hair cells and SGNs in Efr3a knocking down mice (Efr3a−/+, Efr3a KD) and their wild type littermates. Functional examination showed that both groups of mice suffered from serious hearing loss with a higher level of severity in wild type (WT) mice. Morphologic observation following drugs administration showed that both WT and Efr3a KD mice went through progressive loss of hair cells and SGNs, in association with degenerative changes in the perikarya, intracellular organelles, cell body conformation in SGNs, and the changes of SGNs in WT mice were more severe than in Efr3a KD mice. These beneficial effects of Efr3a KD could be ascribed to an increase in the expression of some neurotrophic factors and their receptors in Efr3a KD mice. Our results indicate that Efr3a insufficiency suppresses drug-caused SNHL neurodegeneration in association with an increase in the expression of some neurotrophic factors and their receptors, which may be targeted in the treatment of neurodegeneration.
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Affiliation(s)
- Haixia Hu
- Department of Otolaryngology and Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of MedicineShanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose DiseasesShanghai, China.,Ear Institute, Shanghai Jiao Tong University School of MedicineShanghai, China
| | - Bin Ye
- Department of Otolaryngology and Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of MedicineShanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose DiseasesShanghai, China.,Ear Institute, Shanghai Jiao Tong University School of MedicineShanghai, China
| | - Le Zhang
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of SciencesShanghai, China
| | - Quan Wang
- Department of Otolaryngology and Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of MedicineShanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose DiseasesShanghai, China.,Ear Institute, Shanghai Jiao Tong University School of MedicineShanghai, China
| | - Zhiwei Liu
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing UniversityNanjing, China
| | - Suying Ji
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Institute of Biological Science, Chinese Academy of SciencesShanghai, China
| | - Qiuju Liu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Institute of Biological Science, Chinese Academy of SciencesShanghai, China
| | - Jingrong Lv
- Department of Otolaryngology and Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of MedicineShanghai, China
| | - Yan Ma
- Department of Otolaryngology and Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of MedicineShanghai, China
| | - Ying Xu
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing UniversityNanjing, China
| | - Hao Wu
- Shanghai Key Laboratory of Translational Medicine on Ear and Nose DiseasesShanghai, China.,Ear Institute, Shanghai Jiao Tong University School of MedicineShanghai, China
| | - Fude Huang
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of SciencesShanghai, China.,Institute of Neuroscience and State Key Laboratory of Neuroscience, Institute of Biological Science, Chinese Academy of SciencesShanghai, China
| | - Mingliang Xiang
- Department of Otolaryngology and Head and Neck Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of MedicineShanghai, China.,Shanghai Key Laboratory of Translational Medicine on Ear and Nose DiseasesShanghai, China.,Ear Institute, Shanghai Jiao Tong University School of MedicineShanghai, China
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24
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Qian Q, Liu Q, Zhou D, Pan H, Liu Z, He F, Ji S, Wang D, Bao W, Liu X, Liu Z, Zhang H, Zhang X, Zhang L, Wang M, Xu Y, Huang F, Luo B, Sun B. Brain-specific ablation of Efr3a promotes adult hippocampal neurogenesis via the brain-derived neurotrophic factor pathway. FASEB J 2017; 31:2104-2113. [PMID: 28193719 DOI: 10.1096/fj.201601207r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 01/17/2017] [Indexed: 11/11/2022]
Abstract
Efr3 is a newly identified plasma membrane protein and plays an important role in the phosphoinositide metabolism on the plasma membrane. However, although it is highly expressed in the brain, the functional significance of Efr3 in the brain is not clear. In the present study, we generated Efr3af/f mice and then crossed them with Nestin-Cre mice to delete Efr3a, one of the Efr3 isoforms, specifically in the brain. We found that brain-specific ablation of Efr3a promoted adult hippocampal neurogenesis by increasing survival and maturation of newborn neurons without affecting their dendritic tree morphology. Moreover, the brain-derived neurotrophic factor (BDNF)-tropomyosin-related kinase B (TrkB) signaling pathway was significantly enhanced in the hippocampus of Efr3a-deficient mice, as reflected by increased expression of BDNF, TrkB, and the downstream molecules, including phospho-MAPK and phospho-Akt. Furthermore, the number of TUNEL+ cells was decreased in the subgranular zone of dentate gyrus in Efr3a-deficient mice compared with that of control mice. Our data suggest that brain-specific deletion of Efr3a could promote adult hippocampal neurogenesis, presumably by upregulating the expression of BDNF and its receptor, TrkB, and therefore provide new insight into the roles of Efr3 in the brain.-Qian, Q., Liu, Q., Zhou, D., Pan, H., Liu, Z., He, F., Ji, S., Wang, D., Bao, W., Liu, X., Liu, Z., Zhang, H., Zhang, X., Zhang, L., Wang, M., Xu, Y., Huang, F., Luo, B., Sun B. Brain-specific ablation of Efr3a promotes adult hippocampal neurogenesis via the brain-derived neurotrophic factor pathway.
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Affiliation(s)
- Qi Qian
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China.,Key Laboratory of Neurobiology of Zhejiang Province, and.,Department of Neurology, First Affiliated Hospital, Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Qiuji Liu
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Shanghai, China
| | - Dongming Zhou
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China.,Key Laboratory of Neurobiology of Zhejiang Province, and
| | - Hongyu Pan
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China.,Key Laboratory of Neurobiology of Zhejiang Province, and
| | - Zhiwei Liu
- Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China; and
| | - Fangping He
- Department of Neurology, First Affiliated Hospital, Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | - Suying Ji
- Institute of Neuroscience, Shanghai Institute of Biological Science, Chinese Academy of Sciences, Shanghai, China
| | - Dongpi Wang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China.,Key Laboratory of Neurobiology of Zhejiang Province, and
| | - Wangxiao Bao
- Department of Neurology, First Affiliated Hospital, Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China
| | | | - Zhaoling Liu
- Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China; and
| | - Heng Zhang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China.,Key Laboratory of Neurobiology of Zhejiang Province, and
| | - Xiaoqin Zhang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China.,Key Laboratory of Neurobiology of Zhejiang Province, and
| | - Ling Zhang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China.,Key Laboratory of Neurobiology of Zhejiang Province, and
| | - Mingkai Wang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China.,Key Laboratory of Neurobiology of Zhejiang Province, and
| | - Ying Xu
- Ministry of Education (MOE) Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, China; and
| | - Fude Huang
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Shanghai, China;
| | - Benyan Luo
- Department of Neurology, First Affiliated Hospital, Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, China;
| | - Binggui Sun
- Department of Neurobiology, Key Laboratory of Medical Neurobiology, Ministry of Health of China, .,Key Laboratory of Neurobiology of Zhejiang Province, and
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25
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Jung SR, Seo JB, Deng Y, Asbury CL, Hille B, Koh DS. Contributions of protein kinases and β-arrestin to termination of protease-activated receptor 2 signaling. ACTA ACUST UNITED AC 2016; 147:255-71. [PMID: 26927499 PMCID: PMC4772372 DOI: 10.1085/jgp.201511477] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Systematic imaging studies and modeling reveal new details of the regulation of the Gq-coupled GPCR, protease-activated receptor 2, by phosphorylation and β-arrestin. Activated Gq protein–coupled receptors (GqPCRs) can be desensitized by phosphorylation and β-arrestin binding. The kinetics and individual contributions of these two mechanisms to receptor desensitization have not been fully distinguished. Here, we describe the shut off of protease-activated receptor 2 (PAR2). PAR2 activates Gq and phospholipase C (PLC) to hydrolyze phosphatidylinositol 4,5-bisphosphate (PIP2) into diacylglycerol and inositol trisphosphate (IP3). We used fluorescent protein–tagged optical probes to monitor several consequences of PAR2 signaling, including PIP2 depletion and β-arrestin translocation in real time. During continuous activation of PAR2, PIP2 was depleted transiently and then restored within a few minutes, indicating fast receptor activation followed by desensitization. Knockdown of β-arrestin 1 and 2 using siRNA diminished the desensitization, slowing PIP2 restoration significantly and even adding a delayed secondary phase of further PIP2 depletion. These effects of β-arrestin knockdown on PIP2 recovery were prevented when serine/threonine phosphatases that dephosphorylate GPCRs were inhibited. Thus, PAR2 may continuously regain its activity via dephosphorylation when there is insufficient β-arrestin to trap phosphorylated receptors. Similarly, blockers of protein kinase C (PKC) and G protein–coupled receptor kinase potentiated the PIP2 depletion. In contrast, an activator of PKC inhibited receptor activation, presumably by augmenting phosphorylation of PAR2. Our interpretations were strengthened by modeling. Simulations supported the conclusions that phosphorylation of PAR2 by protein kinases initiates receptor desensitization and that recruited β-arrestin traps the phosphorylated state of the receptor, protecting it from phosphatases. Speculative thinking suggested a sequestration of phosphatidylinositol 4-phosphate 5 kinase (PIP5K) to the plasma membrane by β-arrestin to explain why knockdown of β-arrestin led to secondary depletion of PIP2. Indeed, artificial recruitment of PIP5K removed the secondary loss of PIP2 completely. Altogether, our experimental and theoretical approaches demonstrate roles and dynamics of the protein kinases, β-arrestin, and PIP5K in the desensitization of PAR2.
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Affiliation(s)
- Seung-Ryoung Jung
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Jong Bae Seo
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Yi Deng
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Duk-Su Koh
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195 Department of Physics, Pohang University of Science and Technology, Pohang, Kyungbuk, 790-784, Republic of Korea
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26
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Olender T, Keydar I, Pinto JM, Tatarskyy P, Alkelai A, Chien MS, Fishilevich S, Restrepo D, Matsunami H, Gilad Y, Lancet D. The human olfactory transcriptome. BMC Genomics 2016; 17:619. [PMID: 27515280 PMCID: PMC4982115 DOI: 10.1186/s12864-016-2960-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 07/21/2016] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Olfaction is a versatile sensory mechanism for detecting thousands of volatile odorants. Although molecular basis of odorant signaling is relatively well understood considerable gaps remain in the complete charting of all relevant gene products. To address this challenge, we applied RNAseq to four well-characterized human olfactory epithelial samples and compared the results to novel and published mouse olfactory epithelium as well as 16 human control tissues. RESULTS We identified 194 non-olfactory receptor (OR) genes that are overexpressed in human olfactory tissues vs. CONTROLS The highest overexpression is seen for lipocalins and bactericidal/permeability-increasing (BPI)-fold proteins, which in other species include secreted odorant carriers. Mouse-human discordance in orthologous lipocalin expression suggests different mammalian evolutionary paths in this family. Of the overexpressed genes 36 have documented olfactory function while for 158 there is little or no previous such functional evidence. The latter group includes GPCRs, neuropeptides, solute carriers, transcription factors and biotransformation enzymes. Many of them may be indirectly implicated in sensory function, and ~70 % are over expressed also in mouse olfactory epithelium, corroborating their olfactory role. Nearly 90 % of the intact OR repertoire, and ~60 % of the OR pseudogenes are expressed in the olfactory epithelium, with the latter showing a 3-fold lower expression. ORs transcription levels show a 1000-fold inter-paralog variation, as well as significant inter-individual differences. We assembled 160 transcripts representing 100 intact OR genes. These include 1-4 short 5' non-coding exons with considerable alternative splicing and long last exons that contain the coding region and 3' untranslated region of highly variable length. Notably, we identified 10 ORs with an intact open reading frame but with seemingly non-functional transcripts, suggesting a yet unreported OR pseudogenization mechanism. Analysis of the OR upstream regions indicated an enrichment of the homeobox family transcription factor binding sites and a consensus localization of a specific transcription factor binding site subfamily (Olf/EBF). CONCLUSIONS We provide an overview of expression levels of ORs and auxiliary genes in human olfactory epithelium. This forms a transcriptomic view of the entire OR repertoire, and reveals a large number of over-expressed uncharacterized human non-receptor genes, providing a platform for future discovery.
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Affiliation(s)
- Tsviya Olender
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
| | - Ifat Keydar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Jayant M Pinto
- Section of Otolaryngology-Head and Neck Surgery, University of Chicago, Chicago, IL, USA
| | - Pavlo Tatarskyy
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Anna Alkelai
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Ming-Shan Chien
- Department of Molecular Genetics and Microbiology, Department of Neurobiology, Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC, USA
| | - Simon Fishilevich
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Diego Restrepo
- Department of Cell and Developmental Biology, Neuroscience Program, and Rocky Mountain Taste and Smell Center, University of Colorado School of Medicine, Aurora, CO, USA
| | - Hiroaki Matsunami
- Department of Molecular Genetics and Microbiology, Department of Neurobiology, Duke Institute for Brain Sciences, Duke University Medical Center, Durham, NC, USA
| | - Yoav Gilad
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Doron Lancet
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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27
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Płóciennikowska A, Hromada-Judycka A, Dembinńska J, Roszczenko P, Ciesielska A, Kwiatkowska K. Contribution of CD14 and TLR4 to changes of the PI(4,5)P2
level in LPS-stimulated cells. J Leukoc Biol 2016; 100:1363-1373. [DOI: 10.1189/jlb.2vma1215-577r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 06/12/2016] [Accepted: 06/29/2016] [Indexed: 01/09/2023] Open
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28
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Gross C. Defective phosphoinositide metabolism in autism. J Neurosci Res 2016; 95:1161-1173. [PMID: 27376697 DOI: 10.1002/jnr.23797] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/26/2016] [Accepted: 06/01/2016] [Indexed: 12/12/2022]
Abstract
Phosphoinositides are essential components of lipid membranes and crucial regulators of many cellular functions, including signal transduction, vesicle trafficking, membrane receptor localization and activity, and determination of membrane identity. These functions depend on the dynamic and highly regulated metabolism of phosphoinositides and require finely balanced activity of specific phosphoinositide kinases and phosphatases. There is increasing evidence from genetic and functional studies that these enzymes are often dysregulated or mutated in autism spectrum disorders; in particular, phosphoinositide 3-kinases and their regulatory subunits appear to be affected frequently. Examples of autism spectrum disorders with defective phosphoinositide metabolism are fragile X syndrome and autism disorders associated with mutations in the phosphoinositide 3-phosphatase tensin homolog deleted on chromosome 10 (PTEN), but recent genetic analyses also suggest that select nonsyndromic, idiopathic forms of autism may have altered activity of phosphoinositide kinases and phosphatases. Isoform-specific inhibitors for some of the phosphoinositide kinases have already been developed for cancer research and treatment, and a few are being evaluated for use in humans. Altogether, this offers exciting opportunities to explore altered phosphoinositide metabolism as a therapeutic target in individuals with certain forms of autism. This review summarizes genetic and functional studies identifying defects in phosphoinositide metabolism in autism and related disorders, describes published preclinical work targeting phosphoinositide 3-kinases in neurological diseases, and discusses the opportunities and challenges ahead to translate these findings from animal models and human cells into clinical application in humans. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Christina Gross
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.,Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio
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