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Hernandez-Lara MA, Richard J, Deshpande DA. Diacylglycerol kinase is a keystone regulator of signaling relevant to the pathophysiology of asthma. Am J Physiol Lung Cell Mol Physiol 2024; 327:L3-L18. [PMID: 38742284 PMCID: PMC11380957 DOI: 10.1152/ajplung.00091.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 04/05/2024] [Accepted: 04/23/2024] [Indexed: 05/16/2024] Open
Abstract
Signal transduction by G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and immunoreceptors converge at the activation of phospholipase C (PLC) for the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). This is a point for second-messenger bifurcation where DAG via protein kinase C (PKC) and IP3 via calcium activate distinct protein targets and regulate cellular functions. IP3 signaling is regulated by multiple calcium influx and efflux proteins involved in calcium homeostasis. A family of lipid kinases belonging to DAG kinases (DGKs) converts DAG to phosphatidic acid (PA), negatively regulating DAG signaling and pathophysiological functions. PA, through a series of biochemical reactions, is recycled to produce new molecules of PIP2. Therefore, DGKs act as a central switch in terminating DAG signaling and resynthesis of membrane phospholipids precursor. Interestingly, calcium and PKC regulate the activation of α and ζ isoforms of DGK that are predominantly expressed in airway and immune cells. Thus, DGK forms a feedback and feedforward control point and plays a crucial role in fine-tuning phospholipid stoichiometry, signaling, and functions. In this review, we discuss the previously underappreciated complex and intriguing DAG/DGK-driven mechanisms in regulating cellular functions associated with asthma, such as contraction and proliferation of airway smooth muscle (ASM) cells and inflammatory activation of immune cells. We highlight the benefits of manipulating DGK activity in mitigating salient features of asthma pathophysiology and shed light on DGK as a molecule of interest for heterogeneous diseases such as asthma.
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Affiliation(s)
- Miguel A Hernandez-Lara
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - Joshua Richard
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
| | - Deepak A Deshpande
- Department of Medicine, Center for Translational Medicine, Jane & Leonard Korman Respiratory Institute, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, United States
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2
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Kim CW, Lee JM, Park SW. Divergent roles of the regulatory subunits of class IA PI3K. Front Endocrinol (Lausanne) 2024; 14:1152579. [PMID: 38317714 PMCID: PMC10839044 DOI: 10.3389/fendo.2023.1152579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 12/11/2023] [Indexed: 02/07/2024] Open
Abstract
The regulatory subunit of phosphatidylinositol 3-kinase (PI3K), known as p85, is a critical component in the insulin signaling pathway. Extensive research has shed light on the diverse roles played by the two isoforms of p85, namely p85α and p85β. The gene pik3r1 encodes p85α and its variants, p55α and p50α, while pik3r2 encodes p85β. These isoforms exhibit various activities depending on tissue types, nutrient availability, and cellular stoichiometry. Whole-body or liver-specific deletion of pik3r1 have shown to display increased insulin sensitivity and improved glucose homeostasis; however, skeletal muscle-specific deletion of p85α does not exhibit any significant effects on glucose homeostasis. On the other hand, whole-body deletion of pik3r2 shows improved insulin sensitivity with no significant impact on glucose tolerance. Meanwhile, liver-specific double knockout of pik3r1 and pik3r2 leads to reduced insulin sensitivity and glucose tolerance. In the context of obesity, upregulation of hepatic p85α or p85β has been shown to improve glucose homeostasis. However, hepatic overexpression of p85α in the absence of p50α and p55α results in increased insulin resistance in obese mice. p85α and p85β have distinctive roles in cancer development. p85α acts as a tumor suppressor, but p85β promotes tumor progression. In the immune system, p85α facilitates B cell development, while p85β regulates T cell differentiation and maturation. This review provides a comprehensive overview of the distinct functions attributed to p85α and p85β, highlighting their significance in various physiological processes, including insulin signaling, cancer development, and immune system regulation.
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Affiliation(s)
- Cho-Won Kim
- Division of Endocrinology, Boston Children’s Hospital, Boston, MA, United States
- Department of Pediatrics, Harvard Medical School, Boston, MA, United States
| | - Junsik M. Lee
- Division of Endocrinology, Boston Children’s Hospital, Boston, MA, United States
| | - Sang Won Park
- Division of Endocrinology, Boston Children’s Hospital, Boston, MA, United States
- Department of Pediatrics, Harvard Medical School, Boston, MA, United States
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3
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Wu W, Xia X, Tang L, Luo J, Xiong S, Ma G, Lei H. Phosphoinositide 3-kinase as a therapeutic target in angiogenic disease. Exp Eye Res 2023; 236:109646. [PMID: 37716399 DOI: 10.1016/j.exer.2023.109646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 08/30/2023] [Accepted: 09/05/2023] [Indexed: 09/18/2023]
Abstract
Phosphoinositide 3-kinases (PI3Ks) generate lipids that control multitudinous intracellular cell signaling events which participate in cell survival and proliferation. In addition, PI3K signaling also contributes to metabolism, immunity, angiogenesis and cardiovascular homeostasis, and many diseases. The diverse actions of PI3K stem from the existence of their various isoforms and a variety of protein effectors. Hence, PI3K isoform-specific inhibitors have already achieved a wonderful effect on treating cancer. Herein, we summarize the molecular mechanism of PI3K inhibitors in preventing the permeability of vessels and neovascularization. Additionally, we briefly illustrate how PI3K signaling modulates blood vessel growth and discuss the different roles that PI3K isoforms play in angiogenesis.
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Affiliation(s)
- Wenyi Wu
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.
| | - Xiaobo Xia
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Luosheng Tang
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jing Luo
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Siqi Xiong
- Department of Ophthalmology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Ophthalmology, Changsha, China; National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Gaoen Ma
- Department of Ophthalmology, The First Affiliated Hospital of Hainan Medical University, Haikou, 571199, China.
| | - Hetian Lei
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China.
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4
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Cabral-Dias R, Antonescu CN. Control of phosphatidylinositol-3-kinase signaling by nanoscale membrane compartmentalization. Bioessays 2023; 45:e2200196. [PMID: 36567275 DOI: 10.1002/bies.202200196] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 09/12/2022] [Accepted: 12/13/2022] [Indexed: 12/27/2022]
Abstract
Phosphatidylinositol-3-kinases (PI3Ks) are lipid kinases that produce 3-phosphorylated derivatives of phosphatidylinositol upon activation by various cues. These 3-phosphorylated lipids bind to various protein effectors to control many cellular functions. Lipid phosphatases such as phosphatase and tensin homolog (PTEN) terminate PI3K-derived signals and are critical to ensure appropriate signaling outcomes. Many lines of evidence indicate that PI3Ks and PTEN, as well as some specific lipid effectors are highly compartmentalized, either in plasma membrane nanodomains or in endosomal compartments. We examine the evidence for specific recruitment of PI3Ks, PTEN, and other related enzymes to membrane nanodomains and endocytic compartments. We then examine the hypothesis that scaffolding of the sources (PI3Ks), terminators (PTEN), and effectors of these lipid signals with a common plasma membrane nanodomain may achieve highly localized lipid signaling and ensure selective activation of specific effectors. This highlights the importance of spatial regulation of PI3K signaling in various physiological and disease contexts.
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Affiliation(s)
- Rebecca Cabral-Dias
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Toronto Metropolitan University, Toronto, Ontario, Canada
| | - Costin N Antonescu
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Toronto Metropolitan University, Toronto, Ontario, Canada
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5
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Galarreta CI, Kennedy C, Blair DR, Slavotinek A. Expanding the phenotype of PIK3C2A related syndrome: Report of two siblings with novel features and genotype. Am J Med Genet A 2022; 188:2724-2731. [PMID: 35770347 DOI: 10.1002/ajmg.a.62881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/05/2022] [Accepted: 04/15/2022] [Indexed: 01/25/2023]
Abstract
A pair of siblings was ascertained due to multiple congenital anomalies, including strikingly similar facial, skeletal, and ocular abnormalities. Exome sequencing of both the children and their mother revealed two novel PIK3C2A variants in the siblings, c.4381delC (p.Arg1461Glufs*31) and c.1555C > T (p.Arg519Ter). PIK3C2A belongs to the Class IIa family of Phosphatidylinositol-3-kinases, which create second messenger lipids that regulate a wide range of downstream signaling pathways involved in cell growth, survival and migration. Tiosano et al. (2019) identified the first monogenic disorder associated with biallelic PIK3C2A loss-of-function variants (oculoskeletodental syndrome). The novel syndrome was characterized by short stature, coarse facial features, ocular and skeletal abnormalities. This report describes two additional siblings affected by the PIK3C2A-related syndrome, confirms core clinical features, establishes intrafamilial variability and expands the phenotype to include proteinuria.
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Affiliation(s)
- Carolina I Galarreta
- Medical Genetics and Metabolism Department, Valley Children's Hospital, Madera, California, USA
| | - Colleen Kennedy
- Medical Genetics and Metabolism Department, Valley Children's Hospital, Madera, California, USA
| | - David R Blair
- Department of Pediatrics, Division of Genetics, University of California, San Francisco, California, USA
| | - Anne Slavotinek
- Department of Pediatrics, Division of Genetics, University of California, San Francisco, California, USA
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6
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Gupta S, Kumar M, Chaudhuri S, Kumar A. The non-canonical nuclear functions of key players of the PI3K-AKT-MTOR pathway. J Cell Physiol 2022; 237:3181-3204. [PMID: 35616326 DOI: 10.1002/jcp.30782] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/05/2022] [Accepted: 05/02/2022] [Indexed: 12/29/2022]
Abstract
The PI3K-AKT-MTOR signal transduction pathway is one of the essential signalling cascades within the cell due to its involvement in many vital functions. The pathway initiates with the recruitment of phosphatidylinositol-3 kinases (PI3Ks) onto the plasma membrane, generating phosphatidylinositol-3,4,5-triphosphate [PtdIns(3,4,5)P3 ] and subsequently activating AKT. Being the central node of the PI3K network, AKT activates the mechanistic target of rapamycin kinase complex 1 (MTORC1) via Tuberous sclerosis complex 2 inhibition in the cytoplasm. Although the cytoplasmic role of the pathway has been widely explored for decades, we now know that most of the effector molecules of the PI3K axis diverge from the canonical route and translocate to other cell organelles including the nucleus. The presence of phosphoinositides (PtdIns) inside the nucleus itself indicates the existence of a nuclear PI3K signalling. The nuclear localization of these signaling components is evident in regulating many nuclear processes like DNA replication, transcription, DNA repair, maintenance of genomic integrity, chromatin architecture, and cell cycle control. Here, our review intends to present a comprehensive overview of the nuclear functions of the PI3K-AKT-MTOR signaling biomolecules.
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Affiliation(s)
- Sakshi Gupta
- Department of Molecular Reproduction, Development & Genetics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Mukund Kumar
- Department of Molecular Reproduction, Development & Genetics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Soumi Chaudhuri
- Department of Molecular Reproduction, Development & Genetics, Indian Institute of Science, Bangalore, Karnataka, India
| | - Arun Kumar
- Department of Molecular Reproduction, Development & Genetics, Indian Institute of Science, Bangalore, Karnataka, India
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7
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Wan S, Sun X, Tang W, Wang L, Wu Z, Sun X. Exosome-Depleted Excretory-Secretory Products of the Fourth-Stage Larval Angiostrongylus cantonensis Promotes Alternative Activation of Macrophages Through Metabolic Reprogramming by the PI3K-Akt Pathway. Front Immunol 2021; 12:685984. [PMID: 34367145 PMCID: PMC8343011 DOI: 10.3389/fimmu.2021.685984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/07/2021] [Indexed: 12/19/2022] Open
Abstract
Angiostrongylus cantonensis (AC), which parasitizes in the brain of the non-permissive host, such as mouse and human, is an etiologic agent of eosinophilic meningitis. Excretory-secretory (ES) products play an important role in the interaction between parasites and hosts’ immune responses. Inflammatory macrophages are responsible for eosinophilic meningitis induced by AC, and the soluble antigens of Angiostrongylus cantonensis fourth stage larva (AC L4), a mimic of dead AC L4, aggravate eosinophilic meningitis in AC-infected mice model via promoting alternative activation of macrophages. In this study, we investigated the key molecules in the ES products of AC L4 on macrophages and observed the relationship between metabolic reprogramming and the PI3K-Akt pathway. First, a co-culture system of macrophage and AC L4 was established to define the role of AC L4 ES products on macrophage polarization. Then, AC L4 exosome and exosome-depleted excretory-secretory products (exofree) were separated from AC L4 ES products using differential centrifugation, and their distinct roles on macrophage polarization were confirmed using qPCR and ELISA experiments. Moreover, AC L4 exofree induced alternative activation of macrophages, which is partially associated with metabolic reprogramming by the PI3K-Akt pathway. Next, lectin blot and deglycosylation assay were done, suggesting the key role of N-linked glycoproteins in exofree. Then, glycoproteomic analysis of exofree and RNA-seq analysis of exofree-treated macrophage were performed. Bi-layer PPI network analysis based on these results identified macrophage-related protein Hexa as a key molecule in inducing alternative activation of macrophages. Our results indicate a great value for research of helminth-derived immunoregulatory molecules, which might contribute to drug development for immune-related diseases.
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Affiliation(s)
- Shuo Wan
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China.,The First Affiliated Hospital, Jinan University, Guangzhou, China
| | - Xiaoqiang Sun
- Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Zhongshan School of Mathematics, Sun Yat-Sen University, Guangzhou, China
| | - Wenyan Tang
- Department of Neonatology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Lifu Wang
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Zhongdao Wu
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
| | - Xi Sun
- Department of Parasitology of Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China.,Key Laboratory of Tropical Disease Control (SYSU), Ministry of Education, Guangzhou, China.,Provincial Engineering Technology Research Center for Biological Vector Control, Guangzhou, China
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8
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Class II phosphatidylinositol 3-kinase isoforms in vesicular trafficking. Biochem Soc Trans 2021; 49:893-901. [PMID: 33666217 PMCID: PMC8106491 DOI: 10.1042/bst20200835] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/12/2021] [Accepted: 02/16/2021] [Indexed: 01/14/2023]
Abstract
Phosphatidylinositol 3-kinases (PI3Ks) are critical regulators of many cellular processes including cell survival, proliferation, migration, cytoskeletal reorganization, and intracellular vesicular trafficking. They are a family of lipid kinases that phosphorylate membrane phosphoinositide lipids at the 3′ position of their inositol rings, and in mammals they are divided into three classes. The role of the class III PI3K Vps34 is well-established, but recent evidence suggests the physiological significance of class II PI3K isoforms in vesicular trafficking. This review focuses on the recently discovered functions of the distinct PI3K-C2α and PI3K-C2β class II PI3K isoforms in clathrin-mediated endocytosis and consequent endosomal signaling, and discusses recently reported data on class II PI3K isoforms in different physiological contexts in comparison with class I and III isoforms.
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9
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Choi YB, Cousins E, Nicholas J. Novel Functions and Virus-Host Interactions Implicated in Pathogenesis and Replication of Human Herpesvirus 8. Recent Results Cancer Res 2021; 217:245-301. [PMID: 33200369 DOI: 10.1007/978-3-030-57362-1_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Human herpesvirus 8 (HHV-8) is classified as a γ2-herpesvirus and is related to Epstein-Barr virus (EBV), a γ1-herpesvirus. One important aspect of the γ-herpesviruses is their association with neoplasia, either naturally or in animal model systems. HHV-8 is associated with B-cell-derived primary effusion lymphoma (PEL) and multicentric Castleman's disease (MCD), endothelial-derived Kaposi's sarcoma (KS), and KSHV inflammatory cytokine syndrome (KICS). EBV is also associated with a number of B-cell malignancies, such as Burkitt's lymphoma, Hodgkin's lymphoma, and posttransplant lymphoproliferative disease, in addition to epithelial nasopharyngeal and gastric carcinomas. Despite the similarities between these viruses and their associated malignancies, the particular protein functions and activities involved in key aspects of virus biology and neoplastic transformation appear to be quite distinct. Indeed, HHV-8 specifies a number of proteins for which counterparts had not previously been identified in EBV, other herpesviruses, or even viruses in general, and these proteins are believed to play vital functions in virus biology and to be involved centrally in viral pathogenesis. Additionally, a set of microRNAs encoded by HHV-8 appears to modulate the expression of multiple host proteins to provide conditions conductive to virus persistence within the host and possibly contributing to HHV-8-induced neoplasia. Here, we review the molecular biology underlying these novel virus-host interactions and their potential roles in both virus biology and virus-associated disease.
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Affiliation(s)
- Young Bong Choi
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA.
| | - Emily Cousins
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA
| | - John Nicholas
- Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, Department of Oncology, Johns Hopkins University School of Medicine, 1650 Orleans Street, Baltimore, MD, 21287, USA
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10
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Liu H, Paddock MN, Wang H, Murphy CJ, Geck RC, Navarro AJ, Wulf GM, Elemento O, Haucke V, Cantley LC, Toker A. The INPP4B Tumor Suppressor Modulates EGFR Trafficking and Promotes Triple-Negative Breast Cancer. Cancer Discov 2020; 10:1226-1239. [PMID: 32513774 DOI: 10.1158/2159-8290.cd-19-1262] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/22/2020] [Accepted: 06/02/2020] [Indexed: 11/16/2022]
Abstract
Inactivation of the tumor suppressor lipid phosphatase INPP4B is common in triple-negative breast cancer (TNBC). We generated a genetically engineered TNBC mouse model deficient in INPP4B. We found a dose-dependent increase in tumor incidence in INPP4B homozygous and heterozygous knockout mice compared with wild-type (WT), supporting a role for INPP4B as a tumor suppressor in TNBC. Tumors derived from INPP4B knockout mice are enriched for AKT and MEK gene signatures. Consequently, mice with INPP4B deficiency are more sensitive to PI3K or MEK inhibitors compared with WT mice. Mechanistically, we found that INPP4B deficiency increases PI(3,4)P2 levels in endocytic vesicles but not at the plasma membrane. Moreover, INPP4B loss delays degradation of EGFR and MET, while promoting recycling of receptor tyrosine kinases (RTK), thus enhancing the duration and amplitude of signaling output upon growth factor stimulation. Therefore, INPP4B inactivation in TNBC promotes tumorigenesis by modulating RTK recycling and signaling duration. SIGNIFICANCE: Inactivation of the lipid phosphatase INPP4B is frequent in TNBC. Using a genetically engineered mouse model, we show that INPP4B functions as a tumor suppressor in TNBC. INPP4B regulates RTK trafficking and degradation, such that loss of INPP4B prolongs both PI3K and ERK activation.This article is highlighted in the In This Issue feature, p. 1079.
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Affiliation(s)
- Hui Liu
- Department of Pathology and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
| | | | - Haibin Wang
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Charles J Murphy
- Meyer Cancer Center, Weill Cornell Medicine, New York, New York.,Englander Institute for Precision Medicine, Weill Cornell Medicine, New York, New York
| | - Renee C Geck
- Department of Pathology and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Adrija J Navarro
- Department of Pathology and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Gerburg M Wulf
- Division of Hematology/Oncology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - Olivier Elemento
- Englander Institute for Precision Medicine, Weill Cornell Medicine, New York, New York
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Lewis C Cantley
- Meyer Cancer Center, Weill Cornell Medicine, New York, New York.
| | - Alex Toker
- Department of Pathology and Cancer Center, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts. .,Ludwig Center at Harvard, Boston, Massachusetts
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11
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Aki S, Yoshioka K, Takuwa N, Takuwa Y. TGFβ receptor endocytosis and Smad signaling require synaptojanin1, PI3K-C2α-, and INPP4B-mediated phosphoinositide conversions. Mol Biol Cell 2020; 31:360-372. [PMID: 31913757 PMCID: PMC7183790 DOI: 10.1091/mbc.e19-11-0662] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Phosphoinositide conversion regulates a diverse array of dynamic membrane events including endocytosis. However, it is not well understood which enzymes are involved in phosphoinositide conversions for receptor endocytosis. We found by small interfering RNA (siRNA)-mediated knockdown (KD) that class II PI3K α-isoform (PI3K-C2α), the 5'-phosphatase synaptojanin1 (Synj1), and the 4'-phosphatase INPP4B, but not PI3K-C2β, Synj2, or INPP4A, were required for TGFβ-induced endocytosis of TGFβ receptor. TGFβ induced rapid decreases in PI(4,5)P2 at the plasma membrane (PM) with increases in PI(4)P, followed by increases in PI(3,4)P2, in a TGFβ receptor kinase ALK5-dependent manner. TGFβ induced the recruitment of both synaptojanin1 and PI3K-C2α to the PM with their substantial colocalization. Knockdown of synaptojanin1 abolished TGFβ-induced PI(4,5)P2 decreases and PI(4)P increases. Interestingly, PI3K-C2α KD abolished not only TGFβ-induced PI(3,4)P2 increases but also TGFβ-induced synaptojanin1 recruitment to the PM, PI(4,5)P2 decreases, and PI(4)P increases. Finally, the phosphoinositide conversions were necessary for TGFβ-induced activation of Smad2 and Smad3. These observations demonstrate that the sequential phosphoinositide conversions mediated by Synj1, PI3K-C2α, and INPP4B are essential for TGFβ receptor endocytosis and its signaling.
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Affiliation(s)
- Sho Aki
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8640, Japan
| | - Kazuaki Yoshioka
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8640, Japan
| | - Noriko Takuwa
- Department of Health Science, Ishikawa Prefectural University, Kahoku, Ishikawa 929-1210, Japan
| | - Yoh Takuwa
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8640, Japan
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12
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Lagundžin D, Hu WF, Law HCH, Krieger KL, Qiao F, Clement EJ, Drincic AT, Nedić O, Naldrett MJ, Alvarez S, Woods NT. Delineating the role of FANCA in glucose-stimulated insulin secretion in β cells through its protein interactome. PLoS One 2019; 14:e0220568. [PMID: 31461451 PMCID: PMC6713327 DOI: 10.1371/journal.pone.0220568] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/18/2019] [Indexed: 12/31/2022] Open
Abstract
Hyperinsulinemia affects 72% of Fanconi anemia (FA) patients and an additional 25% experience lowered glucose tolerance or frank diabetes. The underlying molecular mechanisms contributing to the dysfunction of FA pancreas β cells is unknown. Therefore, we sought to evaluate the functional role of FANCA, the most commonly mutated gene in FA, in glucose-stimulated insulin secretion (GSIS). This study reveals that FANCA or FANCB knockdown impairs GSIS in human pancreas β cell line EndoC-βH3. To identify potential pathways by which FANCA might regulate GSIS, we employed a proteomics approach to identify FANCA protein interactions in EndoC-βH3 differentially regulated in response to elevated glucose levels. Glucose-dependent changes in the FANCA interaction network were observed, including increased association with other FA family proteins, suggesting an activation of the DNA damage response in response to elevated glucose levels. Reactive oxygen species increase in response to glucose stimulation and are necessary for GSIS in EndoC-βH3 cells. Glucose-induced activation of the DNA damage response was also observed as an increase in the DNA damage foci marker γ-H2AX and dependent upon the presence of reactive oxygen species. These results illuminate the role of FANCA in GSIS and its protein interactions regulated by glucose stimulation that may explain the prevalence of β cell-specific endocrinopathies in FA patients.
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Affiliation(s)
- Dragana Lagundžin
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- Mass Spectrometry and Proteomics Core Facility, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Wen-Feng Hu
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Henry C. H. Law
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Kimiko L. Krieger
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Fangfang Qiao
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Emalie J. Clement
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Andjela T. Drincic
- Department of Internal Medicine: Diabetes, Endocrinology and Metabolism, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Olgica Nedić
- Institute for the Application of Nuclear Energy, University of Belgrade, Banatska, Belgrade, Serbia
| | - Michael J. Naldrett
- Proteomics & Metabolomics Facility, Nebraska Center for Biotechnology, University of Nebraska–Lincoln, Nebraska, United States of America
| | - Sophie Alvarez
- Proteomics & Metabolomics Facility, Nebraska Center for Biotechnology, University of Nebraska–Lincoln, Nebraska, United States of America
| | - Nicholas T. Woods
- Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
- * E-mail:
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13
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Sugiyama MG, Fairn GD, Antonescu CN. Akt-ing Up Just About Everywhere: Compartment-Specific Akt Activation and Function in Receptor Tyrosine Kinase Signaling. Front Cell Dev Biol 2019; 7:70. [PMID: 31131274 PMCID: PMC6509475 DOI: 10.3389/fcell.2019.00070] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/09/2019] [Indexed: 12/12/2022] Open
Abstract
The serine/threonine kinase Akt is a master regulator of many diverse cellular functions, including survival, growth, metabolism, migration, and differentiation. Receptor tyrosine kinases are critical regulators of Akt, as a result of activation of phosphatidylinositol-3-kinase (PI3K) signaling leading to Akt activation upon receptor stimulation. The signaling axis formed by receptor tyrosine kinases, PI3K and Akt, as well as the vast range of downstream substrates is thus central to control of cell physiology in many different contexts and tissues. This axis must be tightly regulated, as disruption of PI3K-Akt signaling underlies the pathology of many diseases such as cancer and diabetes. This sophisticated regulation of PI3K-Akt signaling is due in part to the spatial and temporal compartmentalization of Akt activation and function, including in specific nanoscale domains of the plasma membrane as well as in specific intracellular membrane compartments. Here, we review the evidence for localized activation of PI3K-Akt signaling by receptor tyrosine kinases in various specific cellular compartments, as well as that of compartment-specific functions of Akt leading to control of several fundamental cellular processes. This spatial and temporal control of Akt activation and function occurs by a large number of parallel molecular mechanisms that are central to regulation of cell physiology.
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Affiliation(s)
- Michael G. Sugiyama
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Toronto, ON, Canada
| | - Gregory D. Fairn
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Toronto, ON, Canada
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Costin N. Antonescu
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
- Keenan Research Centre for Biomedical Science, St. Michael’s Hospital, Toronto, ON, Canada
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14
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Gulluni F, De Santis MC, Margaria JP, Martini M, Hirsch E. Class II PI3K Functions in Cell Biology and Disease. Trends Cell Biol 2019; 29:339-359. [DOI: 10.1016/j.tcb.2019.01.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/21/2018] [Accepted: 01/02/2019] [Indexed: 12/12/2022]
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15
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Aung KT, Yoshioka K, Aki S, Ishimaru K, Takuwa N, Takuwa Y. The class II phosphoinositide 3-kinases PI3K-C2α and PI3K-C2β differentially regulate clathrin-dependent pinocytosis in human vascular endothelial cells. J Physiol Sci 2019; 69:263-280. [PMID: 30374841 PMCID: PMC10717547 DOI: 10.1007/s12576-018-0644-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/13/2018] [Indexed: 01/18/2023]
Abstract
Pinocytosis is an important fundamental cellular process that is used by the cell to transport fluid and solutes. Phosphoinositide 3-kinases (PI3Ks) regulate a diverse array of dynamic membrane events. However, it is not well-understood which PI3K isoforms are involved in specific mechanisms of pinocytosis. We performed knockdown studies of endogenous PI3K isoforms and clathrin heavy chain (CHC) mediated by small interfering RNA (siRNA). The results demonstrated that the class II PI3K PI3K-C2α and PI3K-C2β, but not the class I or III PI3K, were required for pinocytosis, based on an evaluation of fluorescein-5-isothiocyanate (FITC)-dextran uptake in endothelial cells. Pinocytosis was partially dependent on both clathrin and dynamin, and both PI3K-C2α and PI3K-C2β were required for clathrin-mediated-but not clathrin-non-mediated-FITC-dextran uptake at the step leading up to its delivery to early endosomes. Both PI3K-C2α and PI3K-C2β were co-localized with clathrin-coated pits and vesicles. However, PI3K-C2β, but not PI3K-C2α, was highly co-localized with actin filament-associated clathrin-coated structures and required for actin filament formation at the clathrin-coated structures. These results indicate that PI3K-C2α and PI3K-C2β play differential, indispensable roles in clathrin-mediated pinocytosis.
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Affiliation(s)
- Khin Thuzar Aung
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa, 920-8640, Japan
| | - Kazuaki Yoshioka
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa, 920-8640, Japan
| | - Sho Aki
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa, 920-8640, Japan
| | - Kazuhiro Ishimaru
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa, 920-8640, Japan
| | - Noriko Takuwa
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa, 920-8640, Japan
- Department of Health Science, Ishikawa Prefectural University, Kahoku, Ishikawa, 929-1210, Japan
| | - Yoh Takuwa
- Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa, 920-8640, Japan.
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16
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Molecular Basis for Membrane Recruitment by the PX and C2 Domains of Class II Phosphoinositide 3-Kinase-C2α. Structure 2018; 26:1612-1625.e4. [DOI: 10.1016/j.str.2018.08.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/05/2018] [Accepted: 08/23/2018] [Indexed: 11/17/2022]
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17
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Effective angiogenesis requires regulation of phosphoinositide signaling. Adv Biol Regul 2018; 71:69-78. [PMID: 30503054 DOI: 10.1016/j.jbior.2018.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 12/21/2022]
Abstract
Phosphoinositide signaling regulates numerous downstream effectors that mediate cellular processes which influence cell cycle progression, migration, proliferation, growth, survival, metabolism and vesicular trafficking. A prominent role for phosphoinositide 3-kinase, which generates phosphatidylinositol 3,4,5-trisphosphate, a phospholipid that activates a plethora of effectors including AKT and FOXO during embryonic and postnatal angiogenesis, has been described. In addition, phosphatidylinositol 3-phosphate signaling is required for endosomal trafficking, which contributes to vascular remodeling. This review will examine the role phosphoinositide signaling plays in the endothelium and its contribution to sprouting angiogenesis.
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18
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Sánchez-Alegría K, Flores-León M, Avila-Muñoz E, Rodríguez-Corona N, Arias C. PI3K Signaling in Neurons: A Central Node for the Control of Multiple Functions. Int J Mol Sci 2018; 19:ijms19123725. [PMID: 30477115 PMCID: PMC6321294 DOI: 10.3390/ijms19123725] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 11/13/2018] [Accepted: 11/15/2018] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositide 3-kinase (PI3K) signaling contributes to a variety of processes, mediating many aspects of cellular function, including nutrient uptake, anabolic reactions, cell growth, proliferation, and survival. Less is known regarding its critical role in neuronal physiology, neuronal metabolism, tissue homeostasis, and the control of gene expression in the central nervous system in healthy and diseased states. The aim of the present work is to review cumulative evidence regarding the participation of PI3K pathways in neuronal function, focusing on their role in neuronal metabolism and transcriptional regulation of genes involved in neuronal maintenance and plasticity or on the expression of pathological hallmarks associated with neurodegeneration.
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Affiliation(s)
- Karina Sánchez-Alegría
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
| | - Manuel Flores-León
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
| | - Evangelina Avila-Muñoz
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
| | - Nelly Rodríguez-Corona
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
| | - Clorinda Arias
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, AP 70-228, 04510 México, DF, Mexico.
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19
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Kaposi's Sarcoma-Associated Herpesvirus Nonstructural Membrane Protein pK15 Recruits the Class II Phosphatidylinositol 3-Kinase PI3K-C2α To Activate Productive Viral Replication. J Virol 2018; 92:JVI.00544-18. [PMID: 29950425 DOI: 10.1128/jvi.00544-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 06/24/2018] [Indexed: 12/16/2022] Open
Abstract
Kaposi's sarcoma (KS)-associated herpesvirus (KSHV)/human herpesvirus 8 (HHV-8) causes the angiogenic tumor KS and two B-cell malignancies. The KSHV nonstructural membrane protein encoded by the open reading frame (ORF) K15 recruits and activates several cellular proteins, including phospholipase Cγ1 (PLCγ1), components of the NF-κB pathway, as well as members of the Src family of nonreceptor tyrosine kinases, and thereby plays an important role in the activation of angiogenic and inflammatory pathways that contribute to the pathogenesis of KS as well as KSHV productive (lytic) replication. In order to identify novel cellular components involved in the biology of pK15, we immunoprecipitated pK15 from KSHV-infected endothelial cells and identified associated proteins by label-free quantitative mass spectrometry. Cellular proteins interacting with pK15 point to previously unappreciated cellular processes, such as the endocytic pathway, that could be involved in the function of pK15. We found that the class II phosphatidylinositol 3-kinase (PI3K) PI3K-C2α, which is involved in the endocytosis of activated receptor tyrosine kinases and their signaling from intracellular organelles, interacts and colocalizes with pK15 in vesicular structures abundant in the perinuclear area. Further functional analysis revealed that PI3K-C2α contributes to the pK15-dependent phosphorylation of PLCγ1 and Erk1/2. PI3K-C2α also plays a role in KSHV lytic replication, as evidenced by the reduced expression of the viral lytic genes K-bZIP and ORF45 as well as the reduced release of infectious virus in PI3K-C2α-depleted KSHV-infected endothelial cells. Taken together, our results suggest a role of the cellular PI3K-C2α protein in the functional properties of the KSHV pK15 protein.IMPORTANCE The nonstructural membrane protein encoded by open reading frame K15 of Kaposi's sarcoma-associated herpesvirus (KSHV) (HHV8) activates several intracellular signaling pathways that contribute to the angiogenic properties of KSHV in endothelial cells and to its reactivation from latency. A detailed understanding of how pK15 activates these intracellular signaling pathways is a prerequisite for targeting these processes specifically in KSHV-infected cells. By identifying pK15-associated cellular proteins using a combination of immunoprecipitation and mass spectrometry, we provide evidence that pK15-dependent signaling may occur from intracellular vesicles and rely on the endocytotic machinery. Specifically, a class II PI3K, PI3K-C2α, is recruited by pK15 and involved in pK15-dependent intracellular signaling and viral reactivation from latency. These findings are of importance for future intervention strategies that aim to disrupt the activation of intracellular signaling by pK15 in order to antagonize KSHV productive replication and tumorigenesis.
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20
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Wang H, Lo WT, Vujičić Žagar A, Gulluni F, Lehmann M, Scapozza L, Haucke V, Vadas O. Autoregulation of Class II Alpha PI3K Activity by Its Lipid-Binding PX-C2 Domain Module. Mol Cell 2018; 71:343-351.e4. [DOI: 10.1016/j.molcel.2018.06.042] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 05/14/2018] [Accepted: 06/27/2018] [Indexed: 11/30/2022]
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21
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Hauswirth AG, Ford KJ, Wang T, Fetter RD, Tong A, Davis GW. A postsynaptic PI3K-cII dependent signaling controller for presynaptic homeostatic plasticity. eLife 2018; 7:31535. [PMID: 29303480 PMCID: PMC5773188 DOI: 10.7554/elife.31535] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/04/2018] [Indexed: 01/29/2023] Open
Abstract
Presynaptic homeostatic plasticity stabilizes information transfer at synaptic connections in organisms ranging from insect to human. By analogy with principles of engineering and control theory, the molecular implementation of PHP is thought to require postsynaptic signaling modules that encode homeostatic sensors, a set point, and a controller that regulates transsynaptic negative feedback. The molecular basis for these postsynaptic, homeostatic signaling elements remains unknown. Here, an electrophysiology-based screen of the Drosophila kinome and phosphatome defines a postsynaptic signaling platform that includes a required function for PI3K-cII, PI3K-cIII and the small GTPase Rab11 during the rapid and sustained expression of PHP. We present evidence that PI3K-cII localizes to Golgi-derived, clathrin-positive vesicles and is necessary to generate an endosomal pool of PI(3)P that recruits Rab11 to recycling endosomal membranes. A morphologically distinct subdivision of this platform concentrates postsynaptically where we propose it functions as a homeostatic controller for retrograde, trans-synaptic signaling.
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Affiliation(s)
- Anna G Hauswirth
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Kevin J Ford
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Tingting Wang
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Richard D Fetter
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Amy Tong
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States.,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, United States
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22
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Gulluni F, Martini M, De Santis MC, Campa CC, Ghigo A, Margaria JP, Ciraolo E, Franco I, Ala U, Annaratone L, Disalvatore D, Bertalot G, Viale G, Noatynska A, Compagno M, Sigismund S, Montemurro F, Thelen M, Fan F, Meraldi P, Marchiò C, Pece S, Sapino A, Chiarle R, Di Fiore PP, Hirsch E. Mitotic Spindle Assembly and Genomic Stability in Breast Cancer Require PI3K-C2α Scaffolding Function. Cancer Cell 2017; 32:444-459.e7. [PMID: 29017056 DOI: 10.1016/j.ccell.2017.09.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/25/2017] [Accepted: 09/05/2017] [Indexed: 12/11/2022]
Abstract
Proper organization of the mitotic spindle is key to genetic stability, but molecular components of inter-microtubule bridges that crosslink kinetochore fibers (K-fibers) are still largely unknown. Here we identify a kinase-independent function of class II phosphoinositide 3-OH kinase α (PI3K-C2α) acting as limiting scaffold protein organizing clathrin and TACC3 complex crosslinking K-fibers. Downregulation of PI3K-C2α causes spindle alterations, delayed anaphase onset, and aneuploidy, indicating that PI3K-C2α expression is required for genomic stability. Reduced abundance of PI3K-C2α in breast cancer models initially impairs tumor growth but later leads to the convergent evolution of fast-growing clones with mitotic checkpoint defects. As a consequence of altered spindle, loss of PI3K-C2α increases sensitivity to taxane-based therapy in pre-clinical models and in neoadjuvant settings.
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Affiliation(s)
- Federico Gulluni
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy
| | - Miriam Martini
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy.
| | - Maria Chiara De Santis
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy
| | - Carlo Cosimo Campa
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy
| | - Alessandra Ghigo
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy
| | - Jean Piero Margaria
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy
| | - Elisa Ciraolo
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy
| | - Irene Franco
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy
| | - Ugo Ala
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy
| | - Laura Annaratone
- Department of Medical Sciences, University of Torino, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, Turin, Italy
| | - Davide Disalvatore
- IFOM, The FIRC Institute for Molecular Oncology Foundation, Milan, Italy
| | - Giovanni Bertalot
- Program of Molecular Medicine, IEO, European Institute of Oncology, Milan, Italy
| | - Giuseppe Viale
- Division of Pathology, European Institute of Oncology, Milan, Italy; Department of Oncology and Hemato-oncology (DIPO), University of Milan, Milan, Italy
| | - Anna Noatynska
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Mara Compagno
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy; Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Sara Sigismund
- IFOM, The FIRC Institute for Molecular Oncology Foundation, Milan, Italy
| | - Filippo Montemurro
- Unit of Investigative Oncology, Candiolo Cancer Institute - FPO, IRCCS, Candiolo (TO), Italy
| | - Marcus Thelen
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland
| | - Fan Fan
- Department of Biological Science and Bioengineering, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
| | - Patrick Meraldi
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Caterina Marchiò
- Department of Medical Sciences, University of Torino, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Universitaria Città della Salute e della Scienza di Torino, Turin, Italy
| | - Salvatore Pece
- Program of Molecular Medicine, IEO, European Institute of Oncology, Milan, Italy; Department of Oncology and Hemato-oncology (DIPO), University of Milan, Milan, Italy
| | - Anna Sapino
- Department of Medical Sciences, University of Torino, Turin, Italy; Unit of Pathology, Candiolo Cancer Institute - FPO, IRCCS, Candiolo (TO), Italy
| | - Roberto Chiarle
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy; Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Pier Paolo Di Fiore
- IFOM, The FIRC Institute for Molecular Oncology Foundation, Milan, Italy; Program of Molecular Medicine, IEO, European Institute of Oncology, Milan, Italy; Department of Oncology and Hemato-oncology (DIPO), University of Milan, Milan, Italy
| | - Emilio Hirsch
- Molecular Biotechnology Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin 10126, Italy.
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PI3K-C2α knockdown decreases autophagy and maturation of endocytic vesicles. PLoS One 2017; 12:e0184909. [PMID: 28910396 PMCID: PMC5599018 DOI: 10.1371/journal.pone.0184909] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/01/2017] [Indexed: 12/26/2022] Open
Abstract
Phosphoinositide 3-kinase (PI3K) family members are involved in diverse cellular fates including cell growth, proliferation, and survival. While many molecular details are known about the Class I and III PI3Ks, less is known about the Class II PI3Ks. To explore the function of all eight PI3K isoforms in autophagy, we knock down each gene individually and measure autophagy. We find a significant decrease in autophagy following siRNA-mediated PIK3C2A (encoding the Class 2 PI3K, PI3K-C2α) knockdown. This defective autophagy is rescued by exogenous PI3K-C2α, but not kinase-dead PI3K-C2α. Using confocal microscopy, we probe for markers of endocytosis and autophagy, revealing that PI3K-C2α colocalizes with markers of endocytosis. Though endocytic uptake is intact, as demonstrated by transferrin labeling, PIK3C2A knockdown results in vesicle accumulation at the recycling endosome. We isolate distinct membrane sources and observe that PI3K-C2α interacts with markers of endocytosis and autophagy, notably ATG9. Knockdown of either PIK3C2A or ATG9A/B, but not PI3KC3, results in an accumulation of transferrin-positive clathrin coated vesicles and RAB11-positive vesicles at the recycling endosome. Taken together, these results support a role for PI3K-C2α in the proper maturation of endosomes, and suggest that PI3K-C2α may be a critical node connecting the endocytic and autophagic pathways.
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24
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Yoo EJ, Ojiaku CA, Sunder K, Panettieri RA. Phosphoinositide 3-Kinase in Asthma: Novel Roles and Therapeutic Approaches. Am J Respir Cell Mol Biol 2017; 56:700-707. [PMID: 27977296 DOI: 10.1165/rcmb.2016-0308tr] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Asthma manifests as airway hyperresponsiveness and inflammation, including coughing, wheezing, and shortness of breath. Immune cells and airway structural cells orchestrate asthma pathophysiology, leading to mucus secretion, airway narrowing, and obstruction. Phosphoinositide 3-kinase, a lipid kinase, plays a crucial role in many of the cellular and molecular mechanisms driving asthma pathophysiology and represents an attractive therapeutic target. Here, we summarize the diverse roles of phosphoinositide 3-kinase in the pathogenesis of asthma and discuss novel therapeutic approaches to treatment.
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Affiliation(s)
- Edwin J Yoo
- 1 Rutgers Institute for Translational Medicine and Science, Rutgers, the State University of New Jersey, New Brunswick, New Jersey; and.,2 Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Christie A Ojiaku
- 1 Rutgers Institute for Translational Medicine and Science, Rutgers, the State University of New Jersey, New Brunswick, New Jersey; and.,2 Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Krishna Sunder
- 1 Rutgers Institute for Translational Medicine and Science, Rutgers, the State University of New Jersey, New Brunswick, New Jersey; and
| | - Reynold A Panettieri
- 1 Rutgers Institute for Translational Medicine and Science, Rutgers, the State University of New Jersey, New Brunswick, New Jersey; and
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25
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Shiwarski DJ, Darr M, Telmer CA, Bruchez MP, Puthenveedu MA. PI3K class II α regulates δ-opioid receptor export from the trans-Golgi network. Mol Biol Cell 2017; 28:2202-2219. [PMID: 28566554 PMCID: PMC5531736 DOI: 10.1091/mbc.e17-01-0030] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 04/26/2017] [Accepted: 05/23/2017] [Indexed: 12/20/2022] Open
Abstract
The interplay between signaling and trafficking by G protein-coupled receptors (GPCRs) has focused mainly on endocytic trafficking. Whether and how surface delivery of newly synthesized GPCRs is regulated by extracellular signals is less understood. Here we define a signaling-regulated checkpoint at the trans-Golgi network (TGN) that controls the surface delivery of the delta opioid receptor (δR). In PC12 cells, inhibition of phosphoinositide-3 kinase (PI3K) activity blocked export of newly synthesized δR from the Golgi and delivery to the cell surface, similar to treatment with nerve growth factor (NGF). Depletion of class II phosphoinositide-3 kinase α (PI3K C2A), but not inhibition of class I PI3K, blocked δR export to comparable levels and attenuated δR-mediated cAMP inhibition. NGF treatment displaced PI3K C2A from the Golgi and optogenetic recruitment of the PI3K C2A kinase domain to the TGN-induced δR export downstream of NGF. Of importance, PI3K C2A expression promotes export of endogenous δR in primary trigeminal ganglion neurons. Taken together, our results identify PI3K C2A as being required and sufficient for δR export and surface delivery in neuronal cells and suggest that it could be a key modulator of a novel Golgi export checkpoint that coordinates GPCR delivery to the surface.
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Affiliation(s)
- Daniel J Shiwarski
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213.,Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Marlena Darr
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Cheryl A Telmer
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Marcel P Bruchez
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213.,Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213.,Molecular Biosensor and Imaging Center, Carnegie Mellon University, Pittsburgh, PA 15213
| | - Manojkumar A Puthenveedu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213 .,Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA 15213
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Alliouachene S, Bilanges B, Chaussade C, Pearce W, Foukas LC, Scudamore CL, Moniz LS, Vanhaesebroeck B. Inactivation of class II PI3K-C2α induces leptin resistance, age-dependent insulin resistance and obesity in male mice. Diabetologia 2016; 59:1503-1512. [PMID: 27138914 PMCID: PMC4901096 DOI: 10.1007/s00125-016-3963-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 03/24/2016] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS While the class I phosphoinositide 3-kinases (PI3Ks) are well-documented positive regulators of metabolism, the involvement of class II PI3K isoforms (PI3K-C2α, -C2β and -C2γ) in metabolic regulation is just emerging. Organismal inactivation of PI3K-C2β increases insulin signalling and sensitivity, whereas PI3K-C2γ inactivation has a negative metabolic impact. In contrast, the role of PI3K-C2α in organismal metabolism remains unexplored. In this study, we investigated whether kinase inactivation of PI3K-C2α affects glucose metabolism in mice. METHODS We have generated and characterised a mouse line with a constitutive inactivating knock-in (KI) mutation in the kinase domain of the gene encoding PI3K-C2α (Pik3c2a). RESULTS While homozygosity for kinase-dead PI3K-C2α was embryonic lethal, heterozygous PI3K-C2α KI mice were viable and fertile, with no significant histopathological findings. However, male heterozygous mice showed early onset leptin resistance, with a defect in leptin signalling in the hypothalamus, correlating with a mild, age-dependent obesity, insulin resistance and glucose intolerance. Insulin signalling was unaffected in insulin target tissues of PI3K-C2α KI mice, in contrast to previous reports in which downregulation of PI3K-C2α in cell lines was shown to dampen insulin signalling. Interestingly, no metabolic phenotypes were detected in female PI3K-C2α KI mice at any age. CONCLUSIONS/INTERPRETATION Our data uncover a sex-dependent role for PI3K-C2α in the modulation of hypothalamic leptin action and systemic glucose homeostasis. ACCESS TO RESEARCH MATERIALS All reagents are available upon request.
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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.
| | - Claire Chaussade
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
- Galderma R&D, Sophia Antipolis Cedex, France
| | - Wayne Pearce
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Lazaros C Foukas
- Institute of Healthy Ageing and Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Cheryl L Scudamore
- Mary Lyon Centre, MRC Harwell, Harwell Science and Innovation Campus, Harwell, UK
| | - Larissa S Moniz
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
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Chandler P, Kochupurakkal BS, Alam S, Richardson AL, Soybel DI, Kelleher SL. Subtype-specific accumulation of intracellular zinc pools is associated with the malignant phenotype in breast cancer. Mol Cancer 2016; 15:2. [PMID: 26728511 PMCID: PMC4700748 DOI: 10.1186/s12943-015-0486-y] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 12/11/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Zinc (Zn) hyper-accumulates in breast tumors and malignant cell lines compared to normal mammary epithelium. The mechanisms responsible for Zn accumulation and the consequence of Zn dysregulation are poorly understood. METHODS Microarrays were performed to assess differences in the expression of Zn transporters and metallothioneins (MTs) in human breast tumors and breast cancer cell lines. Real-time PCR and immunoblotting were employed to profile Zn transporter expression in representative luminal (T47D), basal (MDA-MB-231), and non-malignant (MCF10A) cell lines. Zn distribution in human tumors was assessed by X-ray fluorescence imaging. Zn distribution and content in cell lines was measured using FluoZin-3 imaging, and quantification and atomic absorption spectroscopy. Functional consequences of ZnT2 over-expression in MDA-MB-231 cells including invasion, proliferation, and cell cycle were measured using Boyden chambers, MTT assays, and flow cytometry, respectively. RESULTS Gene expression profiling of human breast tumors and breast cancer cell lines identified subtype-specific dysregulation in the Zn transporting network. X-ray fluorescence imaging of breast tumor tissues revealed Zn hyper-accumulation at the margins of Luminal breast tumors while Zn was more evenly distributed within Basal tumors. While both T47D and MDA-MB-231 cells hyper-accumulated Zn relative to MCF10A cells, T47D cells accumulated 2.5-fold more Zn compared to MDA-MB-231 cells. FluoZin-3 imaging indicated that Zn was sequestered into numerous large vesicles in T47D cells, but was retained in the cytoplasm and found in fewer and larger, amorphous sub-cellular compartments in MDA-MB-231 cells. The differences in Zn localization mirrored the relative abundance of the Zn transporter ZnT2; T47D cells over-expressed ZnT2, whereas MDA-MB-231 cells did not express ZnT2 protein due to proteasomal degradation. To determine the functional relevance of the lack of ZnT2 in MDA-MB-231cells, cells were transfected to express ZnT2. ZnT2 over-expression led to Zn vesicularization, shifts in cell cycle, enhanced apoptosis, and reduced proliferation and invasion. CONCLUSIONS This comprehensive analysis of the Zn transporting network in malignant breast tumors and cell lines illustrates that distinct subtype-specific dysregulation of Zn management may underlie phenotypic characteristics of breast cancers such as grade, invasiveness, metastatic potential, and response to therapy.
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Affiliation(s)
- Paige Chandler
- The Interdisciplinary Graduate Program in Physiology, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA
- The Department of Cellular and Molecular Physiology, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA
| | - Bose S Kochupurakkal
- Dana Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Samina Alam
- The Department of Cellular and Molecular Physiology, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA
- The Department of Surgery, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA
| | - Andrea L Richardson
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - David I Soybel
- The Department of Cellular and Molecular Physiology, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA
- The Department of Surgery, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA
| | - Shannon L Kelleher
- The Interdisciplinary Graduate Program in Physiology, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA.
- The Department of Cellular and Molecular Physiology, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA.
- The Department of Pharmacology, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA.
- The Department of Surgery, Penn State Hershey College of Medicine, Hershey, PA, 17033, USA.
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Danelishvili L, Bermudez LE. Mycobacterium avium MAV_2941 mimics phosphoinositol-3-kinase to interfere with macrophage phagosome maturation. Microbes Infect 2015; 17:628-37. [PMID: 26043821 PMCID: PMC4554883 DOI: 10.1016/j.micinf.2015.05.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/22/2015] [Indexed: 11/25/2022]
Abstract
Mycobacterium avium subsp hominissuis (M. avium) is a pathogen that infects and survives in macrophages. Previously, we have identified the M. avium MAV_2941 gene encoding a 73 amino acid protein exported by the oligopeptide transporter OppA to the macrophage cytoplasm. Mutations in MAV_2941 were associated with significant impairment of M. avium growth in THP-1 macrophages. In this study, we investigated the molecular mechanism of MAV_2941 action and demonstrated that MAV_2941 interacts with the vesicle trafficking proteins syntaxin-8 (STX8), adaptor-related protein complex 3 (AP-3) complex subunit beta-1 (AP3B1) and Archain 1 (ARCN1) in mononuclear phagocytic cells. Sequencing analysis revealed that the binding site of MAV_2941 is structurally homologous to the human phosphatidylinositol 3-kinase (PI3K) chiefly in the region recognized by vesicle trafficking proteins. The β3A subunit of AP-3, encoded by AP3B1, is essential for trafficking cargo proteins, including lysosomal-associated membrane protein 1 (LAMP-1), to the phagosome and lysosome-related organelles. Here, we show that while the heat-killed M. avium when ingested by macrophages co-localizes with LAMP-1 protein, transfection of MAV_2941 in macrophages results in significant decrease of LAMP-1 co-localization with the heat-killed M. avium phagosomes. Mutated MAV_2941, where the amino acids homologous to the binding region of PI3K were changed, failed to interact with trafficking proteins. Inactivation of the AP3B1 gene led to alteration in the trafficking of LAMP-1. These results suggest that M. avium MAV_2941 interferes with the protein trafficking within macrophages altering the maturation of phagosome.
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Affiliation(s)
- Lia Danelishvili
- Department of Biomedical Sciences, College of Veterinary Medicine, USA
| | - Luiz E Bermudez
- Department of Biomedical Sciences, College of Veterinary Medicine, USA; Department of Microbiology, College of Science, USA; Molecular and Cell Biology Program, Oregon State University, Corvallis, OR 97331, USA.
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Charming neighborhoods on the cell surface: plasma membrane microdomains regulate receptor tyrosine kinase signaling. Cell Signal 2015; 27:1963-76. [PMID: 26163824 DOI: 10.1016/j.cellsig.2015.07.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/07/2015] [Indexed: 12/14/2022]
Abstract
Receptor tyrosine kinases (RTK) are an important family of growth factor and hormone receptors that regulate many aspects of cellular physiology. Ligand binding by RTKs at the plasma membrane elicits activation of many signaling intermediates. The spatial and temporal regulation of RTK signaling within cells is an important determinant of receptor signaling outcome. In particular, the compartmentalization of the plasma membrane into a number of microdomains allows context-specific control of RTK signaling. Indeed various RTKs are recruited to and enriched within specific plasma membrane microdomains under various conditions, including lipid-ordered domains such as caveolae and lipid rafts, clathrin-coated structures, tetraspanin-enriched microdomains, and actin-dependent protrusive membrane microdomains such as dorsal ruffles and invadosomes. We examine the evidence for control of RTK signaling by each of these plasma membrane microdomains, as well as molecular mechanisms for how this spatial organization controls receptor signaling.
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30
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Posor Y, Eichhorn-Grünig M, Haucke V. Phosphoinositides in endocytosis. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:794-804. [DOI: 10.1016/j.bbalip.2014.09.014] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/21/2014] [Accepted: 09/17/2014] [Indexed: 02/04/2023]
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PI3K-C2α: One enzyme for two products coupling vesicle trafficking and signal transduction. FEBS Lett 2015; 589:1552-8. [DOI: 10.1016/j.febslet.2015.05.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 05/04/2015] [Accepted: 05/05/2015] [Indexed: 12/20/2022]
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32
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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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Aki S, Yoshioka K, Okamoto Y, Takuwa N, Takuwa Y. Phosphatidylinositol 3-kinase class II α-isoform PI3K-C2α is required for transforming growth factor β-induced Smad signaling in endothelial cells. J Biol Chem 2015; 290:6086-105. [PMID: 25614622 DOI: 10.1074/jbc.m114.601484] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We have recently demonstrated that the PI3K class II-α isoform (PI3K-C2α), which generates phosphatidylinositol 3-phosphate and phosphatidylinositol 3,4-bisphosphates, plays crucial roles in angiogenesis, by analyzing PI3K-C2α knock-out mice. The PI3K-C2α actions are mediated at least in part through its participation in the internalization of VEGF receptor-2 and sphingosine-1-phosphate receptor S1P1 and thereby their signaling on endosomes. TGFβ, which is also an essential angiogenic factor, signals via the serine/threonine kinase receptor complex to induce phosphorylation of Smad2 and Smad3 (Smad2/3). SARA (Smad anchor for receptor activation) protein, which is localized in early endosomes through its FYVE domain, is required for Smad2/3 signaling. In the present study, we showed that PI3K-C2α knockdown nearly completely abolished TGFβ1-induced phosphorylation and nuclear translocation of Smad2/3 in vascular endothelial cells (ECs). PI3K-C2α was necessary for TGFβ-induced increase in phosphatidylinositol 3,4-bisphosphates in the plasma membrane and TGFβ receptor internalization into the SARA-containing early endosomes, but not for phosphatidylinositol 3-phosphate enrichment or localization of SARA in the early endosomes. PI3K-C2α was also required for TGFβ receptor-mediated formation of SARA-Smad2/3 complex. Inhibition of dynamin, which is required for the clathrin-dependent receptor endocytosis, suppressed both TGFβ receptor internalization and Smad2/3 phosphorylation. TGFβ1 stimulated Smad-dependent VEGF-A expression, VEGF receptor-mediated EC migration, and capillary-like tube formation, which were all abolished by either PI3K-C2α knockdown or a dynamin inhibitor. Finally, TGFβ1-induced microvessel formation in Matrigel plugs was greatly attenuated in EC-specific PI3K-C2α-deleted mice. These observations indicate that PI3K-C2α plays the pivotal role in TGFβ receptor endocytosis and thereby Smad2/3 signaling, participating in angiogenic actions of TGFβ.
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Affiliation(s)
- Sho Aki
- From the Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8640, Japan and
| | - Kazuaki Yoshioka
- From the Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8640, Japan and
| | - Yasuo Okamoto
- From the Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8640, Japan and
| | - Noriko Takuwa
- From the Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8640, Japan and the Department of Health and Medical Sciences, Ishikawa Prefectural Nursing University, Kahoku, Ishikawa 929-1210, Japan
| | - Yoh Takuwa
- From the Department of Physiology, Kanazawa University School of Medicine, Kanazawa, Ishikawa 920-8640, Japan and
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Yamanaka T, Wong HK, Tosaki A, Bauer PO, Wada K, Kurosawa M, Shimogori T, Hattori N, Nukina N. Large-scale RNA interference screening in mammalian cells identifies novel regulators of mutant huntingtin aggregation. PLoS One 2014; 9:e93891. [PMID: 24705917 PMCID: PMC3976342 DOI: 10.1371/journal.pone.0093891] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 03/10/2014] [Indexed: 01/04/2023] Open
Abstract
In polyglutamine (polyQ) diseases including Huntington's disease (HD), mutant proteins containing expanded polyQ stretch form aggregates in neurons. Genetic or RNAi screenings in yeast, C. elegans or Drosophila have identified multiple genes modifying polyQ aggregation, a few of which are confirmed effective in mammals. However, the overall molecular mechanism underlying polyQ protein aggregation in mammalian cells still remains obscure. We here perform RNAi screening in mouse neuro2a cells to identify mammalian modifiers for aggregation of mutant huntingtin, a causative protein of HD. By systematic cell transfection and automated cell image analysis, we screen ∼12000 shRNA clones and identify 111 shRNAs that either suppress or enhance mutant huntingtin aggregation, without altering its gene expression. Classification of the shRNA-targets suggests that genes with various cellular functions such as gene transcription and protein phosphorylation are involved in modifying the aggregation. Subsequent analysis suggests that, in addition to the aggregation-modifiers sensitive to proteasome inhibition, some of them, such as a transcription factor Tcf20, and kinases Csnk1d and Pik3c2a, are insensitive to it. As for Tcf20, which contains polyQ stretches at N-terminus, its binding to mutant huntingtin aggregates is observed in neuro2a cells and in HD model mouse neurons. Notably, except Pik3c2a, the rest of the modifiers identified here are novel. Thus, our first large-scale RNAi screening in mammalian system identifies previously undescribed genetic players that regulate mutant huntingtin aggregation by several, possibly mammalian-specific mechanisms.
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Affiliation(s)
- Tomoyuki Yamanaka
- Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
- Laboratory for Molecular Mechanisms of Thalamus Development, RIKEN Brain Science Institute, Saitama, Japan
- CREST (Core Research for Evolutionary Science and Technology), JST, Tokyo, Japan
| | - Hon Kit Wong
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
- Center for Neurologic Diseases, Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Harvard Institutes of Medicine, Boston, Massachusetts, United States of America
| | - Asako Tosaki
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
| | - Peter O. Bauer
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
| | - Koji Wada
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
| | - Masaru Kurosawa
- Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
- Laboratory for Molecular Mechanisms of Thalamus Development, RIKEN Brain Science Institute, Saitama, Japan
- CREST (Core Research for Evolutionary Science and Technology), JST, Tokyo, Japan
| | - Tomomi Shimogori
- Laboratory for Molecular Mechanisms of Thalamus Development, RIKEN Brain Science Institute, Saitama, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Nobuyuki Nukina
- Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan
- Laboratory for Molecular Mechanisms of Thalamus Development, RIKEN Brain Science Institute, Saitama, Japan
- CREST (Core Research for Evolutionary Science and Technology), JST, Tokyo, Japan
- * E-mail:
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Abstract
Phosphoinositide-3-kinase (PI3K) signaling has been implicated in a panoply of cellular responses including survival, proliferation, protein synthesis, migration, and vesicular trafficking. In addition, alterations in the enzymatic activity of PI3Ks have been involved in the pathogenesis of multiple diseases, ranging from cancer to chronic inflammation. The emerging interest in PI3K as a pharmacological target has prompted the development of several molecules with inhibitory activity. In this context, the quantification of the second messenger generated by PI3Ks, phosphoinositide-3-phosphate, offers an opportunity to directly test variations in the lipid kinase activity of PI3K in physiological as well as pathological conditions. Here, we will describe common methods to measure the lipid kinase activity of PI3K in vitro and new techniques to follow the production of phosphoinositide-3-phosphate in vivo. These methods are relevant to study the alterations of the PI3K systems at the interface between signaling and oncometabolism.
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PtdIns(4)P signalling and recognition systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 991:59-83. [PMID: 23775691 DOI: 10.1007/978-94-007-6331-9_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The Golgi apparatus is a sorting platform that exchanges extensively with the endoplasmic reticulum (ER), endosomes (Es) and plasma membrane (PM) compartments. The last compartment of the Golgi, the trans-Golgi Network (TGN) is a large complex of highly deformed membranes from which vesicles depart to their targeted organelles but also are harbored from retrograde pathways. The phosphoinositide (PI) composition of the TGN is marked by an important contingent of phosphatidylinositol-4-phosphate (PtdIns(4)P). Although this PI is present throughout the Golgi, its proportion grows along the successive cisternae and peaks at the TGN. The levels of this phospholipid are controlled by a set of kinases and phosphatases that regulate its concentrations in the Golgi and maintain a dynamic gradient that determines the cellular localization of several interacting proteins. Though not exclusive to the Golgi, the synthesis of PtdIns(4)P in other membranes is relatively marginal and has unclear consequences. The significance of PtdIns(4)P within the TGN has been demonstrated for numerous cellular events such as vesicle formation, lipid metabolism, and membrane trafficking.
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Krawczyk J, Keane N, Swords R, O'Dwyer M, Freeman CL, Giles FJ. Perifosine--a new option in treatment of acute myeloid leukemia? Expert Opin Investig Drugs 2013; 22:1315-27. [PMID: 23931614 DOI: 10.1517/13543784.2013.826648] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
INTRODUCTION Perifosine is a novel targeted oral Akt inhibitor. In preclinical leukemia models, perifosine has an independent cytotoxic potential but also synergizes well with other rationally selected targeted agents. The evidence from clinical trials supporting the use of perifosine in the therapy of leukemias is limited. The optimal dose and schedule have yet to be defined. However, given its favorable toxicity profile and mechanism of action, the therapeutic potential of perifosine should be evaluated in well-designed clinical trials. AREAS COVERED The role of the phosphatidylinositol-3 kinase (PI3K)/Akt zpathway in normal cells, cancer and leukemias is discussed. The mechanism of action of perifosine and the basic information on the development and chemical properties are summarized. The evidence from in vivo and in vitro studies is presented. The efficacy and side effect profile are summarized. EXPERT OPINION The safety and tolerability profile of perifosine are satisfactory. The evidence from clinical trials in patients with leukemias is very limited. The preclinical data are encouraging. Perifosine has the potential to play a role in the treatment of leukemias in the future. Its role needs to be confirmed in clinical trials.
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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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Garg R, Kapoor V, Mittal M, Singh MK, Shukla NK, Das SN. Abnormal expression of PI3K isoforms in patients with tobacco-related oral squamous cell carcinoma. Clin Chim Acta 2013; 416:100-6. [PMID: 23228846 DOI: 10.1016/j.cca.2012.11.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 11/22/2012] [Accepted: 11/23/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND The phosphatidylinositol 3-kinase (PI3K) signaling regulates several cellular functions such as motility, proliferation, angiogenesis and survival. METHODS Since there is no information on expression of PI3K isoforms in oral cancer, we studied the expression of different isoforms of PI3K (p110α, p110γ, PI3K-C2, Vps34p and p85α) in tumor samples and PBMC by RT and q-RTPCR and serum levels of PI3K p110α by SPR and ELISA techniques in 108 patients with tobacco-related oral squamous cell carcinoma (OSCC) and 46 normal subjects. RESULTS We observed significantly higher PI3K p110α (p<0.0001) and lower (p<0.0001) vesicular sorting protein 34p (Vps34p) mRNA both in PBMC and tissue samples of oral cancer patients as compared to the normal controls. Other PI3K isoforms did not show such change. Circulating PI3K p110α levels were higher in patients (p<0.0001) as compared to healthy subjects, the SPR data showed direct correlation with advancing stage of the disease. PI3K p110α was overexpressed in tumor samples but not in the normal buccal mucosa. CONCLUSIONS Upregulation of circulating PI3K p110α isoform and its direct correlation with increasing tumor load in OSCC patients indicates that it may be a significant prognostic indicator and a suitable target for therapeutic/chemo-preventive strategies for tobacco-related OSCC.
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Affiliation(s)
- Richa Garg
- Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110029, India
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Biswas K, Yoshioka K, Asanuma K, Okamoto Y, Takuwa N, Sasaki T, Takuwa Y. Essential role of class II phosphatidylinositol-3-kinase-C2α in sphingosine 1-phosphate receptor-1-mediated signaling and migration in endothelial cells. J Biol Chem 2012. [PMID: 23192342 DOI: 10.1074/jbc.m112.409656] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The phosphatidylinositol (PtdIns) 3-kinase (PI3K) family regulates diverse cellular processes, including cell proliferation, migration, and vesicular trafficking, through catalyzing 3'-phosphorylation of phosphoinositides. In contrast to class I PI3Ks, including p110α and p110β, functional roles of class II PI3Ks, comprising PI3K-C2α, PI3K-C2β, and PI3K-C2γ, are little understood. The lysophospholipid mediator sphingosine 1-phosphate (S1P) plays the important roles in regulating vascular functions, including vascular formation and barrier integrity, via the G-protein-coupled receptors S1P(1-3). We studied the roles of PI3K-C2α in S1P-induced endothelial cell (EC) migration and tube formation. S1P stimulated cell migration and activation of Akt, ERK, and Rac1, the latter of which acts as a signaling molecule essential for cell migration and tube formation, via S1P(1) in ECs. Knockdown of either PI3K-C2α or class I p110β markedly inhibited S1P-induced migration, lamellipodium formation, and tube formation, whereas that of p110α or Vps34 did not. Only p110β was necessary for S1P-iduced Akt activation, but both PI3K-C2α and p110β were required for Rac1 activation. FRET imaging showed that S1P induced Rac1 activation in both the plasma membrane and PtdIns 3-phosphate (PtdIns(3)P)-enriched endosomes. Knockdown of PI3K-C2α but not p110β markedly reduced PtdIns(3)P-enriched endosomes and suppressed endosomal Rac1 activation. Also, knockdown of PI3K-C2α but not p110β suppressed S1P-induced S1P(1) internalization into PtdIns(3)P-enriched endosomes. Finally, pharmacological inhibition of endocytosis suppressed S1P-induced S1P(1) internalization, Rac1 activation, migration, and tube formation. These observations indicate that PI3K-C2α plays the crucial role in S1P(1) internalization into the intracellular vesicular compartment, Rac1 activation on endosomes, and thereby migration through regulating vesicular trafficking in ECs.
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Affiliation(s)
- Kuntal Biswas
- Department of Physiology, Kanazawa University School of Medicine, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8640, Japan
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Mochizuki Y, Ohashi R, Kawamura T, Iwanari H, Kodama T, Naito M, Hamakubo T. Phosphatidylinositol 3-phosphatase myotubularin-related protein 6 (MTMR6) is regulated by small GTPase Rab1B in the early secretory and autophagic pathways. J Biol Chem 2012. [PMID: 23188820 DOI: 10.1074/jbc.m112.395087] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A large family of myotubularin phosphatases dephosphorylates phosphatidylinositol 3-phosphate and phosphatidylinositol 3,5-bisphosphate, which are known to play important roles in vesicular trafficking and autophagy. The family is composed of 16 members, and understanding their regulatory mechanisms is important to understand their functions and related genetic diseases. We prepared anti-myotubularin-related protein 6 (MTMR6) monoclonal antibody and used it to study the regulatory mechanism of MTMR6. Endogenous MTMR6 was present in the cytoplasm and was condensed in the perinuclear region in a microtubule-dependent manner. MTMR6 preferentially interacted with GDP-bound Rab1B via the GRAM domain and partly overlapped with Rab1B in the pericentrosomal and peri-Golgi regions in normal rat kidney cells. Overexpression of GDP-bound Rab1B and the reduction of Rab1B disrupted the localization of MTMR6, suggesting that Rab1B regulates the localization of MTMR6. The reduction of MTMR6 accelerated the transport of vesicular stomatitis virus glycoprotein in which Rab1B is involved. Furthermore, reduction of MTMR6 or Rab1B inhibited the formation of the tubular omegasome that is induced by overexpression of DFCP1 in autophagy. Our results indicate that the cellular localization of MTMR6 is regulated by Rab1B in the early secretory and autophagic pathways. We propose a new regulatory mechanism of myotubularin phosphatase by the small GTPase Rab1B.
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Affiliation(s)
- Yasuhiro Mochizuki
- Department of Molecular Biology and Medicine, The University of Tokyo, Tokyo 153-8904, Japan.
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42
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Cancino J, Luini A. Signaling Circuits on the Golgi Complex. Traffic 2012; 14:121-34. [DOI: 10.1111/tra.12022] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/12/2012] [Accepted: 10/12/2012] [Indexed: 01/21/2023]
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Endothelial PI3K-C2α, a class II PI3K, has an essential role in angiogenesis and vascular barrier function. Nat Med 2012; 18:1560-9. [PMID: 22983395 DOI: 10.1038/nm.2928] [Citation(s) in RCA: 168] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 08/10/2012] [Indexed: 12/11/2022]
Abstract
The class II α-isoform of phosphatidylinositol 3-kinase (PI3K-C2α) is localized in endosomes, the trans-Golgi network and clathrin-coated vesicles; however, its functional role is not well understood. Global or endothelial-cell-specific deficiency of PI3K-C2α resulted in embryonic lethality caused by defects in sprouting angiogenesis and vascular maturation. PI3K-C2α knockdown in endothelial cells resulted in a decrease in the number of PI3-phosphate-enriched endosomes, impaired endosomal trafficking, defective delivery of VE-cadherin to endothelial cell junctions and defective junction assembly. PI3K-C2α knockdown also impaired endothelial cell signaling, including vascular endothelial growth factor receptor internalization and endosomal RhoA activation. Together, the effects of PI3K-C2α knockdown led to defective endothelial cell migration, proliferation, tube formation and barrier integrity. Endothelial PI3K-C2α deficiency in vivo suppressed postischemic and tumor angiogenesis and diminished vascular barrier function with a greatly augmented susceptibility to anaphylaxis and a higher incidence of dissecting aortic aneurysm formation in response to angiotensin II infusion. Thus, PI3K-C2α has a crucial role in vascular formation and barrier integrity and represents a new therapeutic target for vascular disease.
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Wymann MP, Schultz C. The chemical biology of phosphoinositide 3-kinases. Chembiochem 2012; 13:2022-35. [PMID: 22965647 DOI: 10.1002/cbic.201200089] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 07/13/2012] [Indexed: 01/14/2023]
Abstract
Since its discovery in the late 1980s, phosphoinositide 3-kinase (PI3K), and its isoforms have arguably reached the forefront of signal transduction research. Regulation of this lipid kinase, its functions, its effectors, in short its entire signaling network, has been extensively studied. PI3K inhibitors are frequently used in biochemistry and cell biology. In addition, many pharmaceutical companies have launched drug-discovery programs to identify modulators of PI3Ks. Despite these efforts and a fairly good knowledge of the PI3K signaling network, we still have only a rudimentary picture of the signaling dynamics of PI3K and its lipid products in space and time. It is therefore essential to create and use novel biological and chemical tools to manipulate the phosphoinositide signaling network with spatial and temporal resolution. In this review, we discuss the current and potential future tools that are available and necessary to unravel the various functions of PI3K and its isoforms.
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Affiliation(s)
- Matthias P Wymann
- Institute of Biochemistry & Genetics, Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058 Basel, Switzerland
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Abstract
Neurons can sustain high rates of synaptic transmission without exhausting their supply of synaptic vesicles. This property relies on a highly efficient local endocytic recycling of synaptic vesicle membranes, which can be reused for hundreds, possibly thousands, of exo-endocytic cycles. Morphological, physiological, molecular, and genetic studies over the last four decades have provided insight into the membrane traffic reactions that govern this recycling and its regulation. These studies have shown that synaptic vesicle endocytosis capitalizes on fundamental and general endocytic mechanisms but also involves neuron-specific adaptations of such mechanisms. Thus, investigations of these processes have advanced not only the field of synaptic transmission but also, more generally, the field of endocytosis. This article summarizes current information on synaptic vesicle endocytosis with an emphasis on the underlying molecular mechanisms and with a special focus on clathrin-mediated endocytosis, the predominant pathway of synaptic vesicle protein internalization.
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Affiliation(s)
- Yasunori Saheki
- Department of Cell Biology, Howard Hughes Medical Institute and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, 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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Abstract
Phosphoinositide 3-kinases (PI3Ks) control cell growth, proliferation, cell survival, metabolic activity, vesicular trafficking, degranulation, and migration. Through these processes, PI3Ks modulate vital physiology. When over-activated in disease, PI3K promotes tumor growth, angiogenesis, metastasis or excessive immune cell activation in inflammation, allergy and autoimmunity. This chapter will introduce molecular activation and signaling of PI3Ks, and connections to target of rapamycin (TOR) and PI3K-related protein kinases (PIKKs). The focus will be on class I PI3Ks, and extend into current developments to exploit mechanistic knowledge for therapy.
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Affiliation(s)
- Matthias Wymann
- Institute Biochemistry & Genetics, Department Biomedicine, University of Basel, Mattenstrasse 28, 4058, Basel, Switzerland,
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48
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Abstract
Phosphoinositides play an essential role in insulin signaling, serving as a localization signal for a variety of proteins that participate in the regulation of cellular growth and metabolism. This chapter will examine the regulation and localization of phosphoinositide species, and will explore the roles of these lipids in insulin action. We will also discuss the changes in phosphoinositide metabolism that occur in various pathophysiological states such as insulin resistance and diabetes.
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Affiliation(s)
- Dave Bridges
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
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Gaffield MA, Romberg CF, Betz WJ. Live imaging of bulk endocytosis in frog motor nerve terminals using FM dyes. J Neurophysiol 2011; 106:599-607. [PMID: 21543750 DOI: 10.1152/jn.00123.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We observed endocytosis in real time in stimulated frog motor nerve terminals by imaging the growth of large membrane infoldings labeled with a low concentration of FM dye. The spatial and temporal information made available by these experiments allowed us to image several new aspects of this synaptic vesicle recycling pathway. Membrane infoldings appeared near synaptic vesicle clusters and grew rapidly during long-duration, high-frequency stimulation. In some cases, we observed large, elongated infoldings growing laterally into the terminal. We used these observations to calculate infolding growth rates. A decrease in stimulation frequency caused a decrease in growth rates, but the overall length of these structures was unaffected by frequency changes. Attempts to wash the dye from these infoldings after stimulation were unsuccessful, demonstrating that the fluorescent structures had been endocytosed. We also used this technique to trigger and image infoldings during repeated, short trains. We found that membrane uptake occurred repeatedly at individual endocytosis sites, but only during a portion of the total number of trains delivered to the terminal. Finally, we showed that phosphatidylinositol 3-kinase, but not actin, was involved in this endocytosis pathway. The ability to monitor many individual bulk endocytosis sites in real time should allow for new types of endocytosis measurements and could reveal novel and unexpected mechanisms for coordinating membrane recovery during synaptic activity.
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Affiliation(s)
- Michael A Gaffield
- Department of Physiology and Biophysics, University of Colorado-Denver, Anshutz Medical Campus, Aurora, CO 80045, USA
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Krag C, Malmberg EK, Salcini AE. PI3KC2α, a class II PI3K, is required for dynamin-independent internalization pathways. J Cell Sci 2010; 123:4240-50. [DOI: 10.1242/jcs.071712] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Increasing evidence indicates that cellular uptake of several molecules can occur independently of functional dynamin, but the molecular players that regulate dynamin-independent endocytosis and the subsequent trafficking steps are still largely unknown. A survival-based short-hairpin (sh) RNA screen using a cell line expressing a diphtheria toxin receptor (DTR, officially known as HBEGF) anchored to GPI (DTR–GPI), which internalizes diphtheria toxin (DT, officially known as DTX) in a dynamin-independent manner, identified PI3KC2α, a class II phosphoinositide 3-kinase (PI3K), as a specific regulator of dynamin-independent DT internalization. We found that the internalization of several proteins that enter the cell through dynamin-independent pathways led to a relocalization of PI3KC2α to cargo-positive vesicles. Furthermore, downregulation of PI3KC2α impaired internalization of CD59 as well as fluid-phase endocytosis. Our data suggest a general role for PI3KC2α in regulating physiologically relevant dynamin-independent internalization pathways by recruiting early endosome antigen 1 (EEA1) to vesicular compartments, a step required for the intracellular trafficking of vesicles generated by dynamin-independent endocytic pathways.
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Affiliation(s)
- Claudia Krag
- Biotech Research and Innovation Centre, BRIC, University of Copenhagen, Ole Maaløes Vej 5, DK2200 Copenhagen, Denmark
| | - Emily Kim Malmberg
- Biotech Research and Innovation Centre, BRIC, University of Copenhagen, Ole Maaløes Vej 5, DK2200 Copenhagen, Denmark
| | - Anna Elisabetta Salcini
- Biotech Research and Innovation Centre, BRIC, University of Copenhagen, Ole Maaløes Vej 5, DK2200 Copenhagen, Denmark
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