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Conduit SE, Vanhaesebroeck B. Phosphoinositide lipids in primary cilia biology. Biochem J 2020; 477:3541-3565. [PMID: 32970140 PMCID: PMC7518857 DOI: 10.1042/bcj20200277] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/30/2020] [Accepted: 08/27/2020] [Indexed: 12/11/2022]
Abstract
Primary cilia are solitary signalling organelles projecting from the surface of most cell types. Although the ciliary membrane is continuous with the plasma membrane it exhibits a unique phospholipid composition, a feature essential for normal cilia formation and function. Recent studies have illustrated that distinct phosphoinositide lipid species localise to specific cilia subdomains, and have begun to build a 'phosphoinositide map' of the cilium. The abundance and localisation of phosphoinositides are tightly regulated by the opposing actions of lipid kinases and lipid phosphatases that have also been recently discovered at cilia. The critical role of phosphoinositides in cilia biology is highlighted by the devastating consequences of genetic defects in cilia-associated phosphoinositide regulatory enzymes leading to ciliopathy phenotypes in humans and experimental mouse and zebrafish models. Here we provide a general introduction to primary cilia and the roles phosphoinositides play in cilia biology. In addition to increasing our understanding of fundamental cilia biology, this rapidly expanding field may inform novel approaches to treat ciliopathy syndromes caused by deregulated phosphoinositide metabolism.
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Affiliation(s)
- Sarah E. Conduit
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, U.K
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, U.K
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2
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Kim J, Jung KH, Yoo J, Park JH, Yan HH, Fang Z, Lim JH, Kwon SR, Kim MK, Park HJ, Hong SS. PBT-6, a Novel PI3KC2γ Inhibitor in Rheumatoid Arthritis. Biomol Ther (Seoul) 2020; 28:172-183. [PMID: 31739383 PMCID: PMC7059814 DOI: 10.4062/biomolther.2019.153] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/15/2019] [Accepted: 10/17/2019] [Indexed: 12/29/2022] Open
Abstract
Phosphoinositide 3-kinase (PI3K) is considered as a promising therapeutic target for rheumatoid arthritis (RA) because of its involvement in inflammatory processes. However, limited studies have reported the involvement of PI3KC2γ in RA, and the underlying mechanism remains largely unknown. Therefore, we investigated the role of PI3KC2γ as a novel therapeutic target for RA and the effect of its selective inhibitor, PBT-6. In this study, we observed that PI3KC2γ was markedly increased in the synovial fluid and tissue as well as the PBMCs of patients with RA. PBT-6, a novel PI3KC2γ inhibitor, decreased the cell growth of TNF-mediated synovial fibroblasts and LPS-mediated macrophages. Furthermore, PBT-6 inhibited the PI3KC2γ expression and PI3K/ AKT signaling pathway in both synovial fibroblasts and macrophages. In addition, PBT-6 suppressed macrophage migration via CCL2 and osteoclastogenesis. In CIA mice, it significantly inhibited the progression and development of RA by decreasing arthritis scores and paw swelling. Three-dimensional micro-computed tomography confirmed that PBT-6 enhanced the joint structures in CIA mice. Taken together, our findings suggest that PI3KC2γ is a therapeutic target for RA, and PBT-6 could be developed as a novel PI3KC2γ inhibitor to target inflammatory diseases including RA.
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Affiliation(s)
- Juyoung Kim
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
| | - Kyung Hee Jung
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
| | - Jaeho Yoo
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jung Hee Park
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
| | - Hong Hua Yan
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
| | - Zhenghuan Fang
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
| | - Joo Han Lim
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
| | - Seong-Ryul Kwon
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
| | - Myung Ku Kim
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
| | - Hyun-Ju Park
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Soon-Sun Hong
- Department of Medicine, College of Medicine, Inha University, Incheon 22313, Republic of Korea
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3
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Durrant TN, Hers I. PI3K inhibitors in thrombosis and cardiovascular disease. Clin Transl Med 2020; 9:8. [PMID: 32002690 PMCID: PMC6992830 DOI: 10.1186/s40169-020-0261-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/13/2020] [Indexed: 12/15/2022] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) are lipid kinases that regulate important intracellular signalling and vesicle trafficking events via the generation of 3-phosphoinositides. Comprising eight core isoforms across three classes, the PI3K family displays broad expression and function throughout mammalian tissues, and the (patho)physiological roles of these enzymes in the cardiovascular system present the PI3Ks as potential therapeutic targets in settings such as thrombosis, atherosclerosis and heart failure. This review will discuss the PI3K enzymes and their roles in cardiovascular physiology and disease, with a particular focus on platelet function and thrombosis. The current progress and future potential of targeting the PI3K enzymes for therapeutic benefit in cardiovascular disease will be considered, while the challenges of developing drugs against these master cellular regulators will be discussed.
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Affiliation(s)
- Tom N Durrant
- Department of Chemistry, University of Oxford, Oxford, OX1 3QZ, UK.
| | - Ingeborg Hers
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK.
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4
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Bilanges B, Posor Y, Vanhaesebroeck B. PI3K isoforms in cell signalling and vesicle trafficking. Nat Rev Mol Cell Biol 2019; 20:515-534. [PMID: 31110302 DOI: 10.1038/s41580-019-0129-z] [Citation(s) in RCA: 296] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PI3Ks are a family of lipid kinases that phosphorylate intracellular inositol lipids to regulate signalling and intracellular vesicular traffic. Mammals have eight isoforms of PI3K, divided into three classes. The class I PI3Ks generate 3-phosphoinositide lipids, which directly activate signal transduction pathways. In addition to being frequently genetically activated in cancer, similar mutations in class I PI3Ks have now also been found in a human non-malignant overgrowth syndrome and a primary immune disorder that predisposes to lymphoma. The class II and class III PI3Ks are regulators of membrane traffic along the endocytic route, in endosomal recycling and autophagy, with an often indirect effect on cell signalling. Here, we summarize current knowledge of the different PI3K classes and isoforms, focusing on recently uncovered biological functions and the mechanisms by which these kinases are activated. Deeper insight into the PI3K isoforms will undoubtedly continue to contribute to a better understanding of fundamental cell biological processes and, ultimately, of human disease.
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Affiliation(s)
- Benoit Bilanges
- UCL Cancer Institute, University College London, London, UK.
| | - York Posor
- UCL Cancer Institute, University College London, London, UK.
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5
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Alliouachene S, Bilanges B, Chicanne G, Anderson KE, Pearce W, Ali K, Valet C, Posor Y, Low PC, Chaussade C, Scudamore CL, Salamon RS, Backer JM, Stephens L, Hawkins PT, Payrastre B, Vanhaesebroeck B. Inactivation of the Class II PI3K-C2β Potentiates Insulin Signaling and Sensitivity. Cell Rep 2015; 13:1881-94. [PMID: 26655903 PMCID: PMC4675724 DOI: 10.1016/j.celrep.2015.10.052] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 08/25/2015] [Accepted: 10/15/2015] [Indexed: 11/24/2022] Open
Abstract
In contrast to the class I phosphoinositide 3-kinases (PI3Ks), the organismal roles of the kinase activity of the class II PI3Ks are less clear. Here, we report that class II PI3K-C2β kinase-dead mice are viable and healthy but display an unanticipated enhanced insulin sensitivity and glucose tolerance, as well as protection against high-fat-diet-induced liver steatosis. Despite having a broad tissue distribution, systemic PI3K-C2β inhibition selectively enhances insulin signaling only in metabolic tissues. In a primary hepatocyte model, basal PI3P lipid levels are reduced by 60% upon PI3K-C2β inhibition. This results in an expansion of the very early APPL1-positive endosomal compartment and altered insulin receptor trafficking, correlating with an amplification of insulin-induced, class I PI3K-dependent Akt signaling, without impacting MAPK activity. These data reveal PI3K-C2β as a critical regulator of endosomal trafficking, specifically in insulin signaling, and identify PI3K-C2β as a potential drug target for insulin sensitization.
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Affiliation(s)
- Samira Alliouachene
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK.
| | - Benoit Bilanges
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Gaëtan Chicanne
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432 Toulouse Cedex 4, France
| | - Karen E Anderson
- Inositide Laboratory, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Wayne Pearce
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Khaled Ali
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Colin Valet
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432 Toulouse Cedex 4, France
| | - York Posor
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Pei Ching Low
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Claire Chaussade
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Cheryl L Scudamore
- Mary Lyon Centre, MRC Harwell, Harwell Science and Innovation Campus, Harwell OX11 0RD, UK
| | - Rachel S Salamon
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jonathan M Backer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Len Stephens
- Inositide Laboratory, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Phill T Hawkins
- Inositide Laboratory, The Babraham Institute, Cambridge CB22 3AT, UK
| | - Bernard Payrastre
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432 Toulouse Cedex 4, France
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6DD, UK.
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PI3K-C2γ is a Rab5 effector selectively controlling endosomal Akt2 activation downstream of insulin signalling. Nat Commun 2015; 6:7400. [PMID: 26100075 PMCID: PMC4479417 DOI: 10.1038/ncomms8400] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 05/06/2015] [Indexed: 01/09/2023] Open
Abstract
In the liver, insulin-mediated activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway is at the core of metabolic control. Multiple PI3K and Akt isoenzymes are found in hepatocytes and whether isoform-selective interplays exist is currently unclear. Here we report that insulin signalling triggers the association of the liver-specific class II PI3K isoform γ (PI3K-C2γ) with Rab5-GTP, and its recruitment to Rab5-positive early endosomes. In these vesicles, PI3K-C2γ produces a phosphatidylinositol-3,4-bisphosphate pool specifically required for delayed and sustained endosomal Akt2 stimulation. Accordingly, loss of PI3K-C2γ does not affect insulin-dependent Akt1 activation as well as S6K and FoxO1-3 phosphorylation, but selectively reduces Akt2 activation, which specifically inhibits glycogen synthase activity. As a consequence, PI3K-C2γ-deficient mice display severely reduced liver accumulation of glycogen and develop hyperlipidemia, adiposity as well as insulin resistance with age or after consumption of a high-fat diet. Our data indicate PI3K-C2γ supports an isoenzyme-specific forking of insulin-mediated signal transduction to an endosomal pool of Akt2, required for glucose homeostasis. The kinase PI3K is crucial for insulin signalling in the liver but the roles of individual PI3K isoforms are largely unclear. Using mice that lack class II PI3K isoform γ (PI3K-C2γ), the authors here show that PI3K-C2γ selectively activates endosomal Akt2 by regulating the localized production of PIP2.
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7
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Mountford JK, Petitjean C, Putra HWK, McCafferty JA, Setiabakti NM, Lee H, Tønnesen LL, McFadyen JD, Schoenwaelder SM, Eckly A, Gachet C, Ellis S, Voss AK, Dickins RA, Hamilton JR, Jackson SP. The class II PI 3-kinase, PI3KC2α, links platelet internal membrane structure to shear-dependent adhesive function. Nat Commun 2015; 6:6535. [PMID: 25779105 DOI: 10.1038/ncomms7535] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/05/2015] [Indexed: 12/29/2022] Open
Abstract
PI3KC2α is a broadly expressed lipid kinase with critical functions during embryonic development but poorly defined roles in adult physiology. Here we utilize multiple mouse genetic models to uncover a role for PI3KC2α in regulating the internal membrane reserve structure of megakaryocytes (demarcation membrane system) and platelets (open canalicular system) that results in dysregulated platelet adhesion under haemodynamic shear stress. Structural alterations in the platelet internal membrane lead to enhanced membrane tether formation that is associated with accelerated, yet highly unstable, thrombus formation in vitro and in vivo. Notably, agonist-induced 3-phosphorylated phosphoinositide production and cellular activation are normal in PI3KC2α-deficient platelets. These findings demonstrate an important role for PI3KC2α in regulating shear-dependent platelet adhesion via regulation of membrane structure, rather than acute signalling. These studies provide a link between the open canalicular system and platelet adhesive function that has relevance to the primary haemostatic and prothrombotic function of platelets.
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Affiliation(s)
- Jessica K Mountford
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Claire Petitjean
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Harun W Kusuma Putra
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Jonathan A McCafferty
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Natasha M Setiabakti
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Hannah Lee
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Lotte L Tønnesen
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - James D McFadyen
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Simone M Schoenwaelder
- 1] Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia [2] The Heart Research Institute and Charles Perkins Centre, The University of Sydney, Newtown 2050, Australia
| | - Anita Eckly
- Unité mixte de recherche S949 Institut National de la Santé et de la Recherche Médicale, Université de Strasbourg, Etablissement Français du Sang-Alsace 67000, Strasbourg, France
| | - Christian Gachet
- Unité mixte de recherche S949 Institut National de la Santé et de la Recherche Médicale, Université de Strasbourg, Etablissement Français du Sang-Alsace 67000, Strasbourg, France
| | - Sarah Ellis
- Sir Peter MacCallum Department of Oncology, Peter MacCallum Cancer Centre and The University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Anne K Voss
- 1] Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia [2] Department of Medical Biology, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Ross A Dickins
- 1] Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria 3052, Australia [2] Department of Medical Biology, University of Melbourne, Melbourne, Victoria 3052, Australia
| | - Justin R Hamilton
- Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia
| | - Shaun P Jackson
- 1] Australian Centre for Blood Diseases, Monash University, Level 6, 89 Commercial Road, Melbourne, Victoria 3004, Australia [2] The Heart Research Institute and Charles Perkins Centre, The University of Sydney, Newtown 2050, Australia [3] Department of Molecular and Experimental Medicine, The Scripps Research Institute, San Diego, CA 92037, USA
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8
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Anderson D, Cordell HJ, Fakiola M, Francis RW, Syn G, Scaman ESH, Davis E, Miles SJ, McLeay T, Jamieson SE, Blackwell JM. First genome-wide association study in an Australian aboriginal population provides insights into genetic risk factors for body mass index and type 2 diabetes. PLoS One 2015; 10:e0119333. [PMID: 25760438 PMCID: PMC4356593 DOI: 10.1371/journal.pone.0119333] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 01/28/2015] [Indexed: 12/15/2022] Open
Abstract
A body mass index (BMI) >22kg/m2 is a risk factor for type 2 diabetes (T2D) in Aboriginal Australians. To identify loci associated with BMI and T2D we undertook a genome-wide association study using 1,075,436 quality-controlled single nucleotide polymorphisms (SNPs) genotyped (Illumina 2.5M Duo Beadchip) in 402 individuals in extended pedigrees from a Western Australian Aboriginal community. Imputation using the thousand genomes (1000G) reference panel extended the analysis to 6,724,284 post quality-control autosomal SNPs. No associations achieved genome-wide significance, commonly accepted as P<5x10-8. Nevertheless, genes/pathways in common with other ethnicities were identified despite the arrival of Aboriginal people in Australia >45,000 years ago. The top hit (rs10868204 Pgenotyped = 1.50x10-6; rs11140653 Pimputed_1000G = 2.90x10-7) for BMI lies 5’ of NTRK2, the type 2 neurotrophic tyrosine kinase receptor for brain-derived neurotrophic factor (BDNF) that regulates energy balance downstream of melanocortin-4 receptor (MC4R). PIK3C2G (rs12816270 Pgenotyped = 8.06x10-6; rs10841048 Pimputed_1000G = 6.28x10-7) was associated with BMI, but not with T2D as reported elsewhere. BMI also associated with CNTNAP2 (rs6960319 Pgenotyped = 4.65x10-5; rs13225016 Pimputed_1000G = 6.57x10-5), previously identified as the strongest gene-by-environment interaction for BMI in African-Americans. The top hit (rs11240074 Pgenotyped = 5.59x10-6, Pimputed_1000G = 5.73x10-6) for T2D lies 5’ of BCL9 that, along with TCF7L2, promotes beta-catenin’s transcriptional activity in the WNT signaling pathway. Additional hits occurred in genes affecting pancreatic (KCNJ6, KCNA1) and/or GABA (GABRR1, KCNA1) functions. Notable associations observed for genes previously identified at genome-wide significance in other populations included MC4R (Pgenotyped = 4.49x10-4) for BMI and IGF2BP2 Pimputed_1000G = 2.55x10-6) for T2D. Our results may provide novel functional leads in understanding disease pathogenesis in this Australian Aboriginal population.
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Affiliation(s)
- Denise Anderson
- Telethon Kids Institute, The University of Western Australia, Subiaco, Western Australia, 6008, Australia
| | - Heather J. Cordell
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, United Kingdom
| | - Michaela Fakiola
- Telethon Kids Institute, The University of Western Australia, Subiaco, Western Australia, 6008, Australia
- Cambridge Institute for Medical Research, Department of Medicine, and Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Richard W. Francis
- Telethon Kids Institute, The University of Western Australia, Subiaco, Western Australia, 6008, Australia
| | - Genevieve Syn
- Telethon Kids Institute, The University of Western Australia, Subiaco, Western Australia, 6008, Australia
| | - Elizabeth S. H. Scaman
- Telethon Kids Institute, The University of Western Australia, Subiaco, Western Australia, 6008, Australia
| | - Elizabeth Davis
- Telethon Kids Institute, The University of Western Australia, Subiaco, Western Australia, 6008, Australia
- Department of Endocrinology and Diabetes, Princess Margaret Hospital for Children, Subiaco, Western Australia, 6008, Australia
| | - Simon J. Miles
- Ngangganawili Aboriginal Health Service, Wiluna, Western Australia, 6646, Australia
| | - Toby McLeay
- Ngangganawili Aboriginal Health Service, Wiluna, Western Australia, 6646, Australia
| | - Sarra E. Jamieson
- Telethon Kids Institute, The University of Western Australia, Subiaco, Western Australia, 6008, Australia
| | - Jenefer M. Blackwell
- Telethon Kids Institute, The University of Western Australia, Subiaco, Western Australia, 6008, Australia
- Cambridge Institute for Medical Research, Department of Medicine, and Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
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9
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The Role of p110δ in the Development and Activation of B Lymphocytes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 850:119-35. [DOI: 10.1007/978-3-319-15774-0_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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10
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Lupia E, Pigozzi L, Goffi A, Hirsch E, Montrucchio G. Role of phosphoinositide 3-kinase in the pathogenesis of acute pancreatitis. World J Gastroenterol 2014; 20:15190-15199. [PMID: 25386068 PMCID: PMC4223253 DOI: 10.3748/wjg.v20.i41.15190] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Revised: 06/12/2014] [Accepted: 07/22/2014] [Indexed: 02/06/2023] Open
Abstract
A large body of experimental and clinical data supports the notion that inflammation in acute pancreatitis has a crucial role in the pathogenesis of local and systemic damage and is a major determinant of clinical severity. Thus, research has recently focused on molecules that can regulate the inflammatory processes, such as phosphoinositide 3-kinases (PI3Ks), a family of lipid and protein kinases involved in intracellular signal transduction. Studies using genetic ablation or pharmacologic inhibitors of different PI3K isoforms, in particular the class I PI3Kδ and PI3Kγ, have contributed to a greater understanding of the roles of these kinases in the modulation of inflammatory and immune responses. Recent data suggest that PI3Ks are also involved in the pathogenesis of acute pancreatitis. Activation of the PI3K signaling pathway, and in particular of the class IB PI3Kγ isoform, has a significant role in those events which are necessary for the initiation of acute pancreatic injury, namely calcium signaling alteration, trypsinogen activation, and nuclear factor-κB transcription. Moreover, PI3Kγ is instrumental in modulating acinar cell apoptosis, and regulating local neutrophil infiltration and systemic inflammatory responses during the course of experimental acute pancreatitis. The availability of PI3K inhibitors selective for specific isoforms may provide new valuable therapeutic strategies to improve the clinical course of this disease. This article presents a brief summary of PI3K structure and function, and highlights recent advances that implicate PI3Ks in the pathogenesis of acute pancreatitis.
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Braccini L, Ciraolo E, Martini M, Pirali T, Germena G, Rolfo K, Hirsch E. PI3K keeps the balance between metabolism and cancer. Adv Biol Regul 2012; 52:389-405. [PMID: 22884032 DOI: 10.1016/j.jbior.2012.04.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 04/11/2012] [Indexed: 06/01/2023]
Abstract
Epidemiological studies have established a positive correlation between cancer and metabolic disorders, suggesting that aberrant cell metabolism is a common feature of nearly all tumors. To meet their demand of building block molecules, cancer cells switch to a heavily glucose-dependent metabolism. As insulin triggers glucose uptake, most tumors are or become insulin-dependent. However, the effects of insulin and of other similar growth factors are not only limited to metabolic control but also favor tumor growth by stimulating proliferation and survival. A key signaling event mediating these metabolic and proliferative responses is the activation of the phosphatidylinositol-3 kinases (PI3K) pathway. In this review, we will thus discuss the current concepts of tumor metabolism and the opportunity of PI3K-targeted therapies to exploit the "sweet tooth" of cancer cells.
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Affiliation(s)
- L Braccini
- Department of Genetics, Biology and Biochemistry, Molecular Biotechnology Center, University of Torino, Torino, Italy
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Leibiger B, Moede T, Uhles S, Barker CJ, Creveaux M, Domin J, Berggren PO, Leibiger IB. Insulin-feedback via PI3K-C2alpha activated PKBalpha/Akt1 is required for glucose-stimulated insulin secretion. FASEB J 2010; 24:1824-37. [PMID: 20061534 DOI: 10.1096/fj.09-148072] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Phosphatidylinositide 3-kinases (PI3Ks) play central roles in insulin signal transduction. While the contribution of class Ia PI3K members has been extensively studied, the role of class II members remains poorly understood. The diverse actions of class II PI3K-C2alpha have been attributed to its lipid product PI(3)P. By applying pharmacological inhibitors, transient overexpression and small-interfering RNA-based knockdown of PI3K and PKB/Akt isoforms, together with PI-lipid profiling and live-cell confocal and total internal reflection fluorescence microscopy, we now demonstrate that in response to insulin, PI3K-C2alpha generates PI(3,4)P(2), which allows the selective activation of PKBalpha/Akt1. Knockdown of PI3K-C2alpha expression and subsequent reduction of PKBalpha/Akt1 activity in the pancreatic beta-cell impaired glucose-stimulated insulin release, at least in part, due to reduced glucokinase expression and increased AS160 activity. Hence, our results identify signal transduction via PI3K-C2alpha as a novel pathway whereby insulin activates PKB/Akt and thus discloses PI3K-C2alpha as a potential drugable target in type 2 diabetes. The high degree of codistribution of PI3K-C2alpha and PKBalpha/Akt1 with insulin receptor B type, but not A type, in the same plasma membrane microdomains lends further support to the concept that selectivity in insulin signaling is achieved by the spatial segregation of signaling events.
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Affiliation(s)
- Barbara Leibiger
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
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14
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Sasaki T, Takasuga S, Sasaki J, Kofuji S, Eguchi S, Yamazaki M, Suzuki A. Mammalian phosphoinositide kinases and phosphatases. Prog Lipid Res 2009; 48:307-43. [PMID: 19580826 DOI: 10.1016/j.plipres.2009.06.001] [Citation(s) in RCA: 190] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Phosphoinositides are lipids that are present in the cytoplasmic leaflet of a cell's plasma and internal membranes and play pivotal roles in the regulation of a wide variety of cellular processes. Phosphoinositides are molecularly diverse due to variable phosphorylation of the hydroxyl groups of their inositol rings. The rapid and reversible configuration of the seven known phosphoinositide species is controlled by a battery of phosphoinositide kinases and phosphoinositide phosphatases, which are thus critical for phosphoinositide isomer-specific localization and functions. Significantly, a given phosphoinositide generated by different isozymes of these phosphoinositide kinases and phosphatases can have different biological effects. In mammals, close to 50 genes encode the phosphoinositide kinases and phosphoinositide phosphatases that regulate phosphoinositide metabolism and thus allow cells to respond rapidly and effectively to ever-changing environmental cues. Understanding the distinct and overlapping functions of these phosphoinositide-metabolizing enzymes is important for our knowledge of both normal human physiology and the growing list of human diseases whose etiologies involve these proteins. This review summarizes the structural and biological properties of all the known mammalian phosphoinositide kinases and phosphoinositide phosphatases, as well as their associations with human disorders.
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Affiliation(s)
- Takehiko Sasaki
- Department of Pathology and Immunology, Akita University, Graduate School of Medicine, Akita 010-8543, Japan.
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15
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Kok K, Geering B, Vanhaesebroeck B. Regulation of phosphoinositide 3-kinase expression in health and disease. Trends Biochem Sci 2009; 34:115-27. [DOI: 10.1016/j.tibs.2009.01.003] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2008] [Revised: 01/08/2009] [Accepted: 01/08/2009] [Indexed: 11/24/2022]
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16
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Elis W, Triantafellow E, Wolters NM, Sian KR, Caponigro G, Borawski J, Gaither LA, Murphy LO, Finan PM, Mackeigan JP. Down-regulation of class II phosphoinositide 3-kinase alpha expression below a critical threshold induces apoptotic cell death. Mol Cancer Res 2008; 6:614-23. [PMID: 18403640 DOI: 10.1158/1541-7786.mcr-07-0262] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Members of the phosphoinositide 3-kinase (PI3K) family collectively control multiple cellular responses, including proliferation, growth, chemotaxis, and survival. These diverse effects can partly be attributed to the broad range of downstream effectors being regulated by the products of these lipid kinases, the 3'-phosphoinositides. However, an additional layer of complexity is introduced by the existence of multiple PI3K enzyme isoforms. Much has been learned over the last years on the roles of the classes I and III PI3K members in cellular signaling, but little is known about the isoform-specific tasks done by the class II PI3Ks (C2alpha, beta, and gamma). In this study, we used quantitative reverse transcription-PCR and RNA interference in mammalian cells to gain further insight into the function of these lesser studied PI3K enzymes. We find that PI3K-C2alpha, but not PI3K-C2beta, has an important role in controlling cell survival and by using a panel of RNA interference reagents, we were able to determine a critical threshold of PI3K-C2alpha mRNA levels, below which the apoptotic program is switched on, via the intrinsic cell death pathway. In addition, knockdown of PI3K-C2alpha to levels that by themselves do not induce apoptosis sensitize cells to the anticancer agent Taxol (paclitaxel). Lastly, we report that lowering the levels of PI3K-C2alpha in a number of cancer cell lines reduces their proliferation and cell viability, arguing that PI3K inhibitors targeting not only the class Ialpha isoform but also class IIalpha may contribute to an effective anticancer strategy.
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Affiliation(s)
- Winfried Elis
- Van Andel Research Institute, Grand Rapids, MI 49503, USA
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17
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Diorio C, Brisson J, Bérubé S, Pollak M. Genetic Polymorphisms Involved in Insulin-like Growth Factor (IGF) Pathway in Relation to Mammographic Breast Density and IGF Levels. Cancer Epidemiol Biomarkers Prev 2008; 17:880-8. [DOI: 10.1158/1055-9965.epi-07-2500] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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18
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Daimon M, Sato H, Oizumi T, Toriyama S, Saito T, Karasawa S, Jimbu Y, Wada K, Kameda W, Susa S, Yamaguchi H, Emi M, Muramatsu M, Kubota I, Kawata S, Kato T. Association of the PIK3C2G gene polymorphisms with type 2 DM in a Japanese population. Biochem Biophys Res Commun 2007; 365:466-71. [PMID: 17991425 DOI: 10.1016/j.bbrc.2007.10.180] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Accepted: 10/30/2007] [Indexed: 11/15/2022]
Abstract
The associations of five SNPs (SNPs1-5: A-5468G, A-3333G, C-1794T, C437T and T9148C) of the class II phosphoinositide 3-kinase gamma-subunit (PIK3C2G) gene with type 2 diabetes were examined using a population of the Takahata Study (n (M/W): 2930 (1328/1602); age: 63.3+/-10.2 years), a Japanese community-based study. Quantitative association study of the SNPs with HbA1c levels showed significant association for SNPs 2 and 4 (p=0.018 and 0.004, respectively). A case-control association study of SNP 4 with diabetes by multiple logistic regression analysis showed a significant association of the genotype TT of the SNP with an odds ratio of 2.21 (p=0.001) independently of age, gender and BMI. In the NGT subjects, serum fasting insulin levels in the at-risk genotype group of SNP 4 were significantly lower than those in the others (TT, TC, and CC, 4.9+/-2.6, 5.4+/-3.0, and 5.6+/-3.4muU/ml, respectively; p=0.029).
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Affiliation(s)
- Makoto Daimon
- Department of Neurology, Hematology, Metabolism, Endocrinology and Diabetology (DNHMED), Yamagata University School of Medicine, 2-2-2 Iida-Nishi, Yamagata 990-9585, Japan
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19
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Edwards JL, Apicella MA. Neisseria gonorrhoeae PLD directly interacts with Akt kinase upon infection of primary, human, cervical epithelial cells. Cell Microbiol 2006; 8:1253-71. [PMID: 16882030 DOI: 10.1111/j.1462-5822.2006.00707.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Neisseria gonorrhoeae secrets a phospholipase D (NgPLD), which augments complement receptor 3 (CR3)-mediated invasion of cervical epithelial cells. To elucidate the signalling pathways triggered with gonococcus CR3-engagement and the putative function of NgPLD in these events, we analysed the contribution of the phosphoinositide-Akt pathway to cervical infection. Our data indicated that Akt plays a critical role in cervical infection. Inhibition of myosin light chain kinase, PtdIns(4,5)P2, and Akt functions resulted in decreased gonococcus invasion of primary, human, cervical epithelial cells as well as Akt kinase activity. Akt activity was similarly impaired when cervical cells were challenged with NgPLD-mutant gonococci. Conversely, the PI3-kinase inhibitor, LY294002, enhanced gonococcal invasion of, and Akt activity within, primary cervical cells. We demonstrated that NgPLD directly binds to the Akt PH domain and can compete with a natural Akt ligand, PtdIns(3,4,5)P3, for Akt binding. Collectively, our data suggested that NgPLD augments gonococcus invasion of cervical epithelia by interacting with Akt kinase in a PI3-kinase-independent manner, which results in subversion of normal cervical cell signalling.
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Affiliation(s)
- Jennifer L Edwards
- Department of Microbiology, The University of Iowa, Iowa City, IA 52242, USA.
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20
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Frey RS, Gao X, Javaid K, Siddiqui SS, Rahman A, Malik AB. Phosphatidylinositol 3-kinase gamma signaling through protein kinase Czeta induces NADPH oxidase-mediated oxidant generation and NF-kappaB activation in endothelial cells. J Biol Chem 2006; 281:16128-38. [PMID: 16527821 DOI: 10.1074/jbc.m508810200] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We addressed the role of class 1B phosphatidylinositol 3-kinase (PI3K) isoform PI3Kgamma in mediating NADPH oxidase activation and reactive oxidant species (ROS) generation in endothelial cells (ECs) and of PI3Kgamma-mediated oxidant signaling in the mechanism of NF-kappaB activation and intercellular adhesion molecule (ICAM)-1 expression. We used lung microvascular ECs isolated from mice with targeted deletion of the p110gamma catalytic subunit of PI3Kgamma. Tumor necrosis factor (TNF) alpha challenge of wild type ECs caused p110gamma translocation to the plasma membrane and phosphatidylinositol 1,4,5-trisphosphate production coupled to ROS production; however, this response was blocked in p110gamma-/- ECs. ROS production was the result of TNFalpha activation of Ser phosphorylation of NADPH oxidase subunit p47(phox) and its translocation to EC membranes. NADPH oxidase activation failed to occur in p110gamma-/- ECs. Additionally, the TNFalpha-activated NF-kappaB binding to the ICAM-1 promoter, ICAM-1 protein expression, and PMN adhesion to ECs required functional PI3Kgamma. TNFalpha challenge of p110gamma-/- ECs failed to induce phosphorylation of PDK1 and activation of the atypical PKC isoform, PKCzeta. Thus, PI3Kgamma lies upstream of PKCzeta in the endothelium, and its activation is crucial in signaling NADPH oxidase-dependent oxidant production and subsequent NF-kappaB activation and ICAM-1 expression.
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Affiliation(s)
- Randall S Frey
- Department of Pharmacology and Center for Lung and Vascular Biology, the University of Illinois College of Medicine, Chicago, Illinois 60612, USA.
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21
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Hickey FB, Cotter TG. BCR-ABL Regulates Phosphatidylinositol 3-Kinase-p110γ Transcription and Activation and Is Required for Proliferation and Drug Resistance. J Biol Chem 2006; 281:2441-50. [PMID: 16291747 DOI: 10.1074/jbc.m511173200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The BCR-ABL oncogene is the hallmark of chronic myeloid leukemia, a clonal hematopoietic stem cell disorder. BCR-ABL displays constitutive tyrosine kinase activity, required for its transformation ability. Although the molecular mechanisms behind this malignancy are not fully understood, a role for phosphatidylinositol (PI) 3-kinase has been repeatedly described. Here we report the specific up-regulation of the class I(B) catalytic subunit of PI 3-kinase (p110gamma) in response to BCR-ABL expression. We demonstrate that this upregulation is due to increased transcription and is dependent on both PI 3-kinase and MEK activity. We performed in vitro kinase activity assays and show that BCR-ABL also leads to increased p110gamma activity and that this activation requires both G protein-coupled receptor and Ras signaling. In addition, by transfection of cells with dominant negative p110gamma, we determined that this specific PI 3-kinase isoform is involved in both proliferation and the apoptosis resistance associated with chronic myeloid leukemia. The data presented here define for the first time the ability of BCR-ABL to alter the expression levels of PI 3-kinase isoforms and also demonstrate a previously unreported link between BCR-ABL and p110gamma.
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Affiliation(s)
- Fionnuala B Hickey
- Department of Biochemistry, Biosciences Institute, University College Cork, Cork, Ireland
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22
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Kang S, Song J, Kang J, Kang H, Lee D, Lee Y, Park D. Suppression of the alpha-isoform of class II phosphoinositide 3-kinase gene expression leads to apoptotic cell death. Biochem Biophys Res Commun 2005; 329:6-10. [PMID: 15721265 DOI: 10.1016/j.bbrc.2005.01.091] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Indexed: 11/24/2022]
Abstract
Phosphoinositide 3-kinases (PI3Ks) have known to be key enzymes activating intracellular signaling molecules when a number of growth factors bind to their cell surface receptors. PI3Ks are divided into three classes (I, II, and III) and enzymes of each class have different tissue-specificities and physiological functions. Class II PI3Ks consist of three isoforms (alpha,beta,gamma). Although the alpha-isoform (PI3K-C2alpha) is considered ubiquitous and preferentially activated by insulin rather than the beta-isoform, the physiological significance of PI3K-C2alpha is poorly understood. The present study aimed to determine whether PI3K-C2alpha is associated with the suppression of apoptotic cell death. Different sense- and antisense oligonucleotides (ODNs) were synthesized based on the sequence of C2 domain of PI3K-C2alpha gene. Transfection of CHO-IR cells with two different antisense ODNs clearly reduced the protein content as well as mRNA levels of PI3K-C2alpha whereas neither the nonspecific mock- nor sense ODNs affected. The decrease of PI3K-C2alpha gene expression was paralleled by cellular changes indicating apoptotic cell death such as nuclear condensation, formation of apoptotic bodies, and DNA fragmentation. PI3K-C2alpha mRNA levels were also reduced when cells were incubated in growth factor-deficient medium. Supplementing growth factors (serum or insulin) into medium lead to an increase of PI3K-C2alpha mRNA levels. This finding strongly suggests that PI3K-C2alpha is a crucial survival factor.
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Affiliation(s)
- Shinhae Kang
- Technology Innovation Center, Cheju National University, Jeju, Jeju 690-756, Republic of Korea
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23
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Shepherd PR. Mechanisms regulating phosphoinositide 3-kinase signalling in insulin-sensitive tissues. ACTA ACUST UNITED AC 2005; 183:3-12. [PMID: 15654916 DOI: 10.1111/j.1365-201x.2004.01382.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A great deal of evidence has accumulated indicating that the activity of PI 3-kinase is necessary, and in some cases sufficient, for a wide range of insulin's actions in the cell. Most biochemical, genetic and pharmacological studies have focused on identifying potential roles for the class-Ia PI 3-kinases which are rapidly activated following insulin stimulation. However, recent evidence indicates the alpha isoform of class-II PI 3-kinase (PI3K-C2alpha) may also play a role as insulin causes a very rapid activation of this as well. The basic mechanisms by which insulin activates the various members of the PI 3-kinase family are increasingly well understood and these studies reveal multiple mechanisms for modulating the activity and functionality of PI 3-kinase and for down regulating the signals they generate. These include inhibitory phosphorylation events, lipid phosphatases such as PTEN and SHIP2 and inhibitor proteins of the suppressors of cytokine signalling (SOCS) family. The current review will focus on these mechanisms and how defects in these might contribute to the development of insulin resistance.
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Affiliation(s)
- P R Shepherd
- Department of Biochemistry and Molecular Biology, University College London, Gower St, London WC1E 6BT, UK
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24
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El Sheikh SS, Domin J, Tomtitchong P, Abel P, Stamp G, Lalani EN. Topographical expression of class IA and class II phosphoinositide 3-kinase enzymes in normal human tissues is consistent with a role in differentiation. BMC Clin Pathol 2003; 3:4. [PMID: 14563213 PMCID: PMC280660 DOI: 10.1186/1472-6890-3-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Accepted: 10/16/2003] [Indexed: 11/25/2022] Open
Abstract
Background Growth factor, cytokine and chemokine-induced activation of PI3K enzymes constitutes the start of a complex signalling cascade, which ultimately mediates cellular activities such as proliferation, differentiation, chemotaxis, survival, trafficking, and glucose homeostasis. The PI3K enzyme family is divided into 3 classes; class I (subdivided into IA and IB), class II (PI3K-C2α, PI3K-C2β and PI3K-C2γ) and class III PI3K. Expression of these enzymes in human tissue has not been clearly defined. Methods In this study, we analysed the immunohistochemical topographical expression profile of class IA (anti-p85 adaptor) and class II PI3K (PI3K-C2α and PI3K-C2β) enzymes in 104 formalin-fixed, paraffin embedded normal adult human (age 33–71 years, median 44 years) tissue specimens including those from the gastrointestinal, genitourinary, hepatobiliary, endocrine, integument and lymphoid systems. Antibody specificity was verified by Western blotting of cell lysates and peptide blocking studies. Immunohistochemistry intensity was scored from undetectable to strong. Results PI3K enzymes were expressed in selected cell populations of epithelial or mesenchymal origin. Columnar epithelium and transitional epithelia were reactive but mucous secreting and stratified squamous epithelia were not. Mesenchymal elements (smooth muscle and endothelial cells) and glomerular epithelium were only expressed PI3K-C2α while ganglion cells expressed p85 and PI3K-C2β. All three enzymes were detected in macrophages, which served as an internal positive control. None of the three PI3K isozymes was detected in the stem cell/progenitor compartments or in B lymphocyte aggregates. Conclusions Taken together, these data suggest that PI3K enzyme distribution is not ubiquitous but expressed selectively in fully differentiated, non-proliferating cells. Identification of the normal in vivo expression pattern of class IA and class II PI3K paves the way for further analyses which will clarify the role played by these enzymes in inflammatory, neoplastic and other human disease conditions.
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Affiliation(s)
- Soha Salama El Sheikh
- Department of Histopathology, L Block, Hammersmith Hospital Campus, Imperial College, London W12 0NN, UK
| | - Jan Domin
- Department of Renal Medicine, J Block, Hammersmith Hospital Campus, Imperial College, London W12 0NN, UK
| | - Prakitpunthu Tomtitchong
- Department of Histopathology, L Block, Hammersmith Hospital Campus, Imperial College, London W12 0NN, UK
| | - Paul Abel
- Department of Surgery, B Block, Hammersmith Hospital Campus, Imperial College, London W12 0NN, UK
| | - Gordon Stamp
- Department of Histopathology, L Block, Hammersmith Hospital Campus, Imperial College, London W12 0NN, UK
| | - El-Nasir Lalani
- Department of Histopathology, L Block, Hammersmith Hospital Campus, Imperial College, London W12 0NN, UK
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25
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Fry MJ. Phosphoinositide 3-kinase signalling in breast cancer: how big a role might it play? Breast Cancer Res 2001; 3:304-12. [PMID: 11597319 PMCID: PMC138693 DOI: 10.1186/bcr312] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2001] [Revised: 05/22/2001] [Accepted: 06/04/2001] [Indexed: 11/10/2022] Open
Abstract
Phosphoinositide 3-kinase (PI3K) was first identified as a lipid kinase activity associated with the products of viral oncogenes and with activated protein-tyrosine kinases. Since those early studies, the PI3K superfamily has grown to embrace at least 12 structurally and functionally related enzymes present in the human genome, some of which have protein kinase activity but not lipid kinase activity. Evidence is emerging that PI3K superfamily members, and components of PI3K signalling, play a role in the development of many human cancers. In this review, the PI3K family of enzymes and their signalling is reviewed, with particular reference to possible involvement in breast cancer.
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Affiliation(s)
- M J Fry
- School of Animal and Microbial Sciences, University of Reading, Reading, UK.
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Boytim ML, Lilly P, Drouvalakis K, Lyu SC, Jung R, Krensky AM, Clayberger C. A human class II MHC-derived peptide antagonizes phosphatidylinositol 3-kinase to block IL-2 signaling. J Clin Invest 2000; 105:1447-53. [PMID: 10811852 PMCID: PMC315461 DOI: 10.1172/jci8139] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
MHC molecules bind antigenic peptides and present them to T cells. There is a growing body of evidence that MHC molecules also serve other functions. We and others have described synthetic peptides derived from regions of MHC molecules that inhibit T-cell proliferation or cytotoxicity in an allele-nonspecific manner that is independent of interaction with the T-cell receptor. In this report, we describe the mechanism of action of a synthetic MHC class II-derived peptide that blocks T-cell activation induced by IL-2. Both this peptide, corresponding to residues 65-79 of DQA*03011 (DQ 65-79), and rapamycin inhibit p70 S6 kinase activity, but only DQ 65-79 blocks Akt kinase activity, placing the effects of DQ 65-79 upstream of mTOR, a PI kinase family member. DQ 65-79, but not rapamycin, inhibits phosphatidylinositol 3-kinase (PI 3-kinase) activity in vitro. The peptide is taken up by cells, as demonstrated by confocal microscopy. These findings indicate that DQ 65-79 acts as an antagonist with PI 3-kinase, repressing downstream signaling events and inhibiting proliferation. Understanding the mechanism of action of immunomodulatory peptides may provide new insights into T-cell activation and allow the development of novel immunosuppressive agents.
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Affiliation(s)
- M L Boytim
- Program in Immunology, Division of Immunology and Transplantation Biology, Department of Pediatrics, Stanford University, Stanford, California 94305-5407, USA
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27
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Gillham H, Golding MC, Pepperkok R, Gullick WJ. Intracellular movement of green fluorescent protein-tagged phosphatidylinositol 3-kinase in response to growth factor receptor signaling. J Cell Biol 1999; 146:869-80. [PMID: 10459020 PMCID: PMC2156137 DOI: 10.1083/jcb.146.4.869] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Phosphatidylinositol 3-kinase (PI 3-kinase) is a lipid kinase which has been implicated in mitogenesis, protein trafficking, inhibition of apoptosis, and integrin and actin functions. Here we show using a green fluorescent protein-tagged p85 subunit that phosphatidylinositol 3-kinase is distributed throughout the cytoplasm and is localized to focal adhesion complexes in resting NIH-3T3, A431, and MCF-7 cells. Ligand stimulation of an epidermal growth factor receptor/c-erbB-3 chimera expressed in these cells results in a redistribution of p85 to the cell membrane which is independent of the catalytic activity of the enzyme and the integrity of the actin cytoskeleton. The movement is, however, dependent on the phosphorylation status of the erbB-3 chimera. Using rhodamine-labeled epidermal growth factor we show that the phosphatidylinositol 3-kinase and the receptors colocalize in discrete patches on the cell surface. Low concentrations of ligand cause patching only at the periphery of the cells, whereas at high concentrations patches were seen over the whole cell surface. Using green fluorescent protein-tagged fragments of p85 we show that binding to the receptor requires the NH(2)-terminal part of the protein as well as its SH2 domains.
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Affiliation(s)
- Helen Gillham
- Receptor Biology Laboratory, Imperial Cancer Research Fund Molecular Oncology Unit, Imperial College School of Medicine, Hammersmith Hospital, London W12 ONN, United Kingdom
| | - Matthew C.H.M. Golding
- Receptor Biology Laboratory, Imperial Cancer Research Fund Molecular Oncology Unit, Imperial College School of Medicine, Hammersmith Hospital, London W12 ONN, United Kingdom
| | - Rainer Pepperkok
- Digital Imaging Microscopy Laboratory, Imperial Cancer Research Fund, Lincoln's Inn Fields, London WC2A 3PX, United Kingdom
| | - William J. Gullick
- Receptor Biology Laboratory, Imperial Cancer Research Fund Molecular Oncology Unit, Imperial College School of Medicine, Hammersmith Hospital, London W12 ONN, United Kingdom
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Virdee K, Xue L, Hemmings BA, Goemans C, Heumann R, Tolkovsky AM. Nerve growth factor-induced PKB/Akt activity is sustained by phosphoinositide 3-kinase dependent and independent signals in sympathetic neurons. Brain Res 1999; 837:127-42. [PMID: 10433995 DOI: 10.1016/s0006-8993(99)01643-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Phosphoinositide 3-kinase and its downstream effector kinase PKB/Akt have been suggested to have crucial roles in suppressing apoptosis in several classes of neurons. However, few studies have conducted a long-term investigation of either kinase activity, many studies relying instead on use of the phosphoinositide 3-kinase inhibitors wortmannin and LY294002. When we added LY294002 or wortmannin to sympathetic neurons, apoptosis in the presence of nerve growth factor (NGF) was very slow compared to that obtained by NGF deprivation. However, expression of a kinase-inactive mutant of PKB/Akt in the presence of NGF induced apoptosis in a significant proportion of the neurons. To understand this discrepancy, we investigated more closely the regulation of PKB/Akt activity by NGF. NGF stimulation induced a rapid increase in PKB/Akt activity which was sustained at approximately 6-fold up to 24 h. Phosphoinositide 3-kinase was also rapidly activated by NGF. However, concentrations of wortmannin which completely blocked phosphoinositide 3-kinase activity in the neurons inhibited no more than 50-70% of cellular PKB/Akt activity. Similarly, approximately 50% of maximal NGF-stimulated PKB/Akt activity remained elevated at concentrations of LY294002 which completely blocked neurite outgrowth, a process known to be phosphoinositide 3-kinase dependent. We suggest that a proportion of the sustained PKB/Akt activity induced by NGF is mediated by phosphoinositide 3-kinase-independent pathways. These results raise a cautionary note as to the usefulness of LY294002 or wortmannin as tools to dissect the role of PKB/Akt in neuronal survival.
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Affiliation(s)
- K Virdee
- Department of Biochemistry, Tennis Court Road, University of Cambridge, Cambridge CB2 1QW, UK
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Abstract
Biological actions of insulin are mediated by the insulin receptor, a member of a large family of receptor tyrosine kinases (RTK). Signal transduction by the insulin receptor follows a paradigm for RTK signalling. Many intracellular signalling molecules contain multiple modular domains that mediate protein-protein interactions and participate in the formation of signalling complexes. Phosphorylation cascades are also a prominent feature of RTK signalling. Distal pathways are difficult to dissect because branching paths emerge from downstream effectors and several upstream inputs converge upon single branch points. Thus, insulin action is determined by complicated signalling networks rather than simple linear pathways. Interestingly, many signalling molecules downstream from the insulin receptor are also activated by a plethora of RTKs. Therefore, mechanisms that generate specificity are required. In this review we discuss recent advances in the elucidation of specific metabolic insulin signalling pathways related to glucose transport, one of the most distinctive biological actions of insulin. We also present examples of potential mechanisms underlying specificity in insulin signalling including interactions between multiple branching pathways, subcellular compartmentalization, tissue-specific expression of key effectors and modulation of signal frequency and amplitude.
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Affiliation(s)
- F H Nystrom
- Hypertension-Endocrine Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1754, USA
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30
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Rozycka M, Lu YJ, Brown RA, Lau MR, Shipley JM, Fry MJ. cDNA cloning of a third human C2-domain-containing class II phosphoinositide 3-kinase, PI3K-C2gamma, and chromosomal assignment of this gene (PIK3C2G) to 12p12. Genomics 1998; 54:569-74. [PMID: 9878262 DOI: 10.1006/geno.1998.5621] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Phosphoinositide (PI) 3-kinases have been shown to have critical roles in signaling pathways that regulate proliferation, oncogenic transformation, cell survival, cell migration, and intracellular protein trafficking. We have previously used reverse-transcription polymerase chain reaction methods to identify novel PI 3-kinase isoforms in normal human breast and in lymph nodes containing metastatic breast cancer. Here we report the cDNA cloning of a Class II PI 3-kinase found in normal breast tissue. This gene (PIK3C2G) encodes the third distinct protein of the human Class II PI 3-kinase family, PI3K-C2gamma. PIK3C2G was mapped to chromosome 12 at 12p12 by fluorescence in situ hybridization.
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Affiliation(s)
- M Rozycka
- The Breakthrough Toby Robins Breast Cancer Research Centre, Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, United Kingdom
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31
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Ono F, Nakagawa T, Saito S, Owada Y, Sakagami H, Goto K, Suzuki M, Matsuno S, Kondo H. A novel class II phosphoinositide 3-kinase predominantly expressed in the liver and its enhanced expression during liver regeneration. J Biol Chem 1998; 273:7731-6. [PMID: 9516481 DOI: 10.1074/jbc.273.13.7731] [Citation(s) in RCA: 59] [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
We report herein the cloning and characterization of a novel class II phosphoinositide 3-kinase, termed PI3K-IIgamma, from the cDNA library of regenerating rat liver. This cDNA encodes a protein of 1505 amino acids with a calculated molecular mass of 170,972 Da. The amino acid sequence of PI3K-IIgamma is highly similar to those of class II PI 3-kinases, including murine Cpk-m/p170 and human HsC2-PI3K. It contains a C2 domain at the C terminus but no recognizable protein motifs at its N terminus. PI3K-IIgamma displays a restricted substrate specificity for PtdIns and PtdIns 4-P, but not for PtdIns 4,5-P2. By epitope tag immunocytochemistry, the immunoreactivity for PI3K-IIgamma is localized in the juxtanuclear Golgi region at high levels and also in the plasma and nuclear membranes at low levels. By Northern blot analysis and in situ hybridization histochemistry, PI3K-IIgamma mRNA expression is confined to the liver throughout the development with much higher expression in adult liver than in fetal liver. In addition, its expression increases during liver regeneration after partial hepatectomy with maximal expression after the growth period, suggesting that PI3K-IIgamma may function mainly in highly differentiated hepatic cells.
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Affiliation(s)
- F Ono
- Department of Histology, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-77, Japan
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32
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Su TZ, Wang M, Syu LJ, Saltiel AR, Oxender DL. Regulation of system A amino acid transport in 3T3-L1 adipocytes by insulin. J Biol Chem 1998; 273:3173-9. [PMID: 9452428 DOI: 10.1074/jbc.273.6.3173] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The insulin-stimulated uptake of 2-(methylamino)isobutyric acid (MeAIB), a nonmetabolizable substrate for system A, in 3T3-L1 adipocytes was investigated. As cells took on a more adipogenic phenotype, the insulin-stimulated versus the saturable basal MeAIB uptake increased by 5-fold. The induced transport activity showed properties characteristic of system A, with a Km value of 190 microM. The half-life of the induced system A activity was independent of de novo mRNA and protein synthesis and was not accelerated by ambient amino acids, therefore, it was mechanistically distinct from the previously described adaptive and hormonal regulation of system A. Inhibition of mitogen-activated protein kinase kinase by PD98059, Ras farnesylation by PD152440 and B581, p70(S6K) by rapamycin, and phosphatidylinositol 3-kinase (PI 3'-K) by wortmannin and LY294002 revealed that only wortmannin and LY294002 inhibited the insulin-induced MeAIB uptake with IC50 values close to that previously reported for inhibition of PI 3'-K. These results suggest that the Ras/mitogen-activated protein kinase and pp70(S6K) insulin signaling pathways are neither required nor sufficient for insulin stimulation of MeAIB uptake, and activation of PI 3'-K or a wortmannin/LY294002-sensitive pathway may play an important role in regulation of system A transport by insulin in 3T3-L1 cells.
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Affiliation(s)
- T Z Su
- Department of Molecular Biology, Parke-Davis Pharmaceutical Research Division of Warner Lambert Co., Ann Arbor, Michigan 48105, USA
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