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Ghosh C, Kakar R, Hoyle RG, Liu Z, Guo C, Li J, Wang XY, Sun Y. Type I gamma phosphatidylinositol phosphate 5-kinase i5 controls cell sensitivity to interferon. Dev Cell 2024; 59:1028-1042.e5. [PMID: 38452758 PMCID: PMC11043016 DOI: 10.1016/j.devcel.2024.02.005] [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: 07/08/2023] [Revised: 12/21/2023] [Accepted: 02/09/2024] [Indexed: 03/09/2024]
Abstract
The interferon signaling pathway is critical for host defense by serving diverse functions in both innate and adaptive immune responses. Here, we show that type I gamma phosphatidylinositol phosphate 5-kinase i5 (PIPKIγi5), an enzyme that synthesizes phosphatidylinositol-4,5-bisphosphate (PI4,5P2), controls the sensitivity to interferon in both human and mouse cells. PIPKIγi5 directly binds to the interferon-gamma (IFN-γ) downstream effector signal transducer and activator of transcription 1 (STAT1), which suppresses the STAT1 dimerization, IFN-γ-induced STAT1 nuclear translocation, and transcription of IFN-γ-responsive genes. Depletion of PIPKIγi5 significantly enhances IFN-γ signaling and strengthens an antiviral response. In addition, PIPKIγi5-synthesized PI4,5P2 can bind to STAT1 and promote the PIPKIγi5-STAT1 interaction. Similar to its interaction with STAT1, PIPKIγi5 is capable of interacting with other members of the STAT family, including STAT2 and STAT3, thereby suppressing the expression of genes mediated by these transcription factors. These findings identify the function of PIPKIγi5 in immune regulation.
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Affiliation(s)
- Chinmoy Ghosh
- Department of Oral and Craniofacial Molecular Biology, Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Ruchi Kakar
- Department of Oral and Craniofacial Molecular Biology, Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Rosalie G Hoyle
- Department of Medicinal Chemistry, Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Zheng Liu
- Department of Human and Molecular Genetics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Chunqing Guo
- Department of Human and Molecular Genetics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Jiong Li
- Department of Medicinal Chemistry, Institute for Structural Biology, Drug Discovery and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Xiang-Yang Wang
- Department of Human and Molecular Genetics, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Yue Sun
- Department of Oral and Craniofacial Molecular Biology, Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA 23298, USA; Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA.
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Ling P, Ju J, Zhang X, Wei W, Luo J, Li Y, Hai H, Shang B, Cheng H, Wang C, Zhang X, Su J. The Silencing of GhPIP5K2 and GhPIP5K22 Weakens Abiotic Stress Tolerance in Upland Cotton ( Gossypium hirsutum). Int J Mol Sci 2024; 25:1511. [PMID: 38338791 PMCID: PMC10855785 DOI: 10.3390/ijms25031511] [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: 11/21/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 02/12/2024] Open
Abstract
Phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks), essential enzymes in the phosphatidylinositol signaling pathway, are crucial for the abiotic stress responses and the overall growth and development of plants. However, the GhPIP5Ks had not been systematically studied, and their function in upland cotton was unknown. This study identified a total of 28 GhPIP5Ks, and determined their chromosomal locations, gene structures, protein motifs and cis-acting elements via bioinformatics analysis. A quantitative real-time PCR (qRT‒PCR) analysis showed that most GhPIP5Ks were upregulated under different stresses. A virus-induced gene silencing (VIGS) assay indicated that the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities were significantly decreased, while malondialdehyde (MDA) content were significantly increased in GhPIP5K2- and GhPIP5K22-silenced upland cotton plants under abiotic stress. Furthermore, the expression of the stress marker genes GhHSFB2A, GhHSFB2B, GhDREB2A, GhDREB2C, GhRD20-1, GhRD29A, GhBIN2, GhCBL3, GhNHX1, GhPP2C, GhCBF1, GhSnRK2.6 and GhCIPK6 was significantly decreased in the silenced plants after exposure to stress. These results revealed that the silencing of GhPIP5K2 and GhPIP5K22 weakened the tolerance to abiotic stresses. These discoveries provide a foundation for further inquiry into the actions of the GhPIP5K gene family in regulating the response and resistance mechanisms of cotton to abiotic stresses.
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Affiliation(s)
- Pingjie Ling
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Jisheng Ju
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Xueli Zhang
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Wei Wei
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Jin Luo
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Ying Li
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Han Hai
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Bowen Shang
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Hongbo Cheng
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Caixiang Wang
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Xianliang Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences (CAAS), Anyang 455000, China
- Western Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Changji 831100, China
| | - Junji Su
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
- Western Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Changji 831100, China
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3
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Severin S, Gratacap MP, Bouvet L, Borret M, Kpotor AO, Chicanne G, Xuereb JM, Viaud J, Payrastre B. Phosphoinositides take a central stage in regulating blood platelet production and function. Adv Biol Regul 2024; 91:100992. [PMID: 37793962 DOI: 10.1016/j.jbior.2023.100992] [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: 09/18/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023]
Abstract
Blood platelets are produced by megakaryocytes through a complex program of differentiation and play a critical role in hemostasis and thrombosis. These anucleate cells are the target of antithrombotic drugs that prevent them from clumping in cardiovascular disease conditions. Platelets also significantly contribute to various aspects of physiopathology, including interorgan communications, healing, inflammation, and thromboinflammation. Their production and activation are strictly regulated by highly elaborated mechanisms. Among them, those involving inositol lipids have drawn the attention of researchers. Phosphoinositides represent the seven combinatorially phosphorylated forms of the inositol head group of inositol lipids. They play a crucial role in regulating intracellular mechanisms, such as signal transduction, actin cytoskeleton rearrangements, and membrane trafficking, either by generating second messengers or by directly binding to specific domains of effector proteins. In this review, we will explore how phosphoinositides are implicated in controlling platelet production by megakaryocytes and in platelet activation processes. We will also discuss the diversity of phosphoinositides in platelets, their role in granule biogenesis and maintenance, as well as in integrin signaling. Finally, we will address the discovery of a novel pool of phosphatidylinositol 3-monophosphate in the outerleaflet of the plasma membrane of human and mouse platelets.
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Affiliation(s)
- Sonia Severin
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Marie-Pierre Gratacap
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Laura Bouvet
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Maxime Borret
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Afi Oportune Kpotor
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Gaëtan Chicanne
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Jean-Marie Xuereb
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Julien Viaud
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Bernard Payrastre
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France; Laboratoire d'Hématologie, Centre de Référence des Pathologies Plaquettaires, Centre Hospitalier Universitaire de Toulouse Rangueil, F-31432, Toulouse, France.
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Kato M, Watari M, Tsuge T, Zhong S, Gu H, Qu LJ, Fujiwara T, Aoyama T. Redundant function of the Arabidopsis phosphatidylinositol 4-phosphate 5-kinase genes PIP5K4-6 is essential for pollen germination. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 117:212-225. [PMID: 37828913 DOI: 10.1111/tpj.16490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/02/2023] [Accepted: 09/05/2023] [Indexed: 10/14/2023]
Abstract
Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) is a key enzyme producing the signaling lipid phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] in eukaryotes. Although PIP5K genes are reported to be involved in pollen tube germination and growth, the essential roles of PIP5K in these processes remain unclear. Here, we performed a comprehensive genetic analysis of the Arabidopsis thaliana PIP5K4, PIP5K5, and PIP5K6 genes and revealed that their redundant function is essential for pollen germination. Pollen with the pip5k4pip5k5pip5k6 triple mutation was sterile, while pollen germination efficiency and pollen tube growth were reduced in the pip5k6 single mutant and further reduced in the pip5k4pip5k6 and pip5k5pip5k6 double mutants. YFP-fusion proteins, PIP5K4-YFP, PIP5K5-YFP, and PIP5K6-YFP, which could rescue the sterility of the triple mutant pollen, preferentially localized to the tricolpate aperture area and the future germination site on the plasma membrane prior to germination. Triple mutant pollen grains under the germination condition, in which spatiotemporal localization of the PtdIns(4,5)P2 fluorescent marker protein 2xmCHERRY-2xPHPLC as seen in the wild type was abolished, exhibited swelling and rupture of the pollen wall, but neither the conspicuous protruding site nor site-specific deposition of cell wall materials for germination. These data indicate that PIP5K4-6 and their product PtdIns(4,5)P2 are essential for pollen germination, possibly through the establishment of the germination polarity in a pollen grain.
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Affiliation(s)
- Mariko Kato
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Machiko Watari
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Sheng Zhong
- Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Hongya Gu
- Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Li-Jia Qu
- Peking-Tsinghua Center for Life Sciences, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Takashi Fujiwara
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
| | - Takashi Aoyama
- Institute for Chemical Research, Kyoto University, Uji, Kyoto, 611-0011, Japan
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Kakar R, Ghosh C, Sun Y. Phosphoinositide Signaling in Immune Cell Migration. Biomolecules 2023; 13:1705. [PMID: 38136577 PMCID: PMC10741629 DOI: 10.3390/biom13121705] [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: 10/26/2023] [Revised: 11/15/2023] [Accepted: 11/22/2023] [Indexed: 12/24/2023] Open
Abstract
In response to different immune challenges, immune cells migrate to specific sites in the body, where they perform their functions such as defense against infection, inflammation regulation, antigen recognition, and immune surveillance. Therefore, the migration ability is a fundamental aspect of immune cell function. Phosphoinositide signaling plays critical roles in modulating immune cell migration by controlling cell polarization, cytoskeletal rearrangement, protrusion formation, and uropod contraction. Upon chemoattractant stimulation, specific phosphoinositide kinases and phosphatases control the local phosphoinositide levels to establish polarized phosphoinositide distribution, which recruits phosphoinositide effectors to distinct subcellular locations to facilitate cell migration. In this Special Issue of "Molecular Mechanisms Underlying Cell Adhesion and Migration", we discuss the significance of phosphoinositide production and conversion by phosphoinositide kinases and phosphatases in the migration of different types of immune cells.
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Affiliation(s)
| | | | - Yue Sun
- Department of Oral and Craniofacial Molecular Biology, Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA 23298, USA; (R.K.); (C.G.)
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Lee JB, Lim JH, Park HB. Genome-wide association studies to identify quantitative trait loci and positional candidate genes affecting meat quality-related traits in pigs. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2023; 65:1194-1204. [PMID: 38616878 PMCID: PMC11007289 DOI: 10.5187/jast.2023.e70] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/06/2023] [Accepted: 07/11/2023] [Indexed: 04/16/2024]
Abstract
Meat quality comprises a set of key traits such as pH, meat color, water-holding capacity, tenderness and marbling. These traits are complex because they are affected by multiple genetic and environmental factors. The aim of this study was to investigate the molecular genetic basis underlying nine meat quality-related traits in a Yorkshire pig population using a genome-wide association study (GWAS) and subsequent biological pathway analysis. In total, 45,926 single nucleotide polymorphism (SNP) markers from 543 pigs were selected for the GWAS after quality control. Data were analyzed using a genome-wide efficient mixed model association (GEMMA) method. This linear mixed model-based approach identified two quantitative trait loci (QTLs) for meat color (b*) on chromosome 2 (SSC2) and one QTL for shear force on chromosome 8 (SSC8). These QTLs acted additively on the two phenotypes and explained 3.92%-4.57% of the phenotypic variance of the traits of interest. The genes encoding HAUS8 on SSC2 and an lncRNA on SSC8 were identified as positional candidate genes for these QTLs. The results of the biological pathway analysis revealed that positional candidate genes for meat color (b*) were enriched in pathways related to muscle development, muscle growth, intramuscular adipocyte differentiation, and lipid accumulation in muscle, whereas positional candidate genes for shear force were overrepresented in pathways related to cell growth, cell differentiation, and fatty acids synthesis. Further verification of these identified SNPs and genes in other independent populations could provide valuable information for understanding the variations in pork quality-related traits.
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Affiliation(s)
- Jae-Bong Lee
- Korea Zoonosis Research Institute (KoZRI),
Jeonbuk National University, Iksan 54531, Korea
| | - Ji-Hoon Lim
- Department of Animal Resources Science,
Kongju National University, Yesan 32439, Korea
| | - Hee-Bok Park
- Department of Animal Resources Science,
Kongju National University, Yesan 32439, Korea
- Resource Science Research Institute,
Kongju National University, Yesan 32439, Korea
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7
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Revu SK, Yang W, Rajasundaram D, Brady A, Majumder S, Gaffen SL, Hawse W, Xia Z, McGeachy MJ. Human IL-17A protein production is controlled through a PIP5K1α-dependent translational checkpoint. Sci Signal 2023; 16:eabo6555. [PMID: 37874883 PMCID: PMC10880140 DOI: 10.1126/scisignal.abo6555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 10/06/2023] [Indexed: 10/26/2023]
Abstract
The cytokine interleukin-17 (IL-17) is secreted by T helper 17 (TH17) cells and is beneficial for microbial control; however, it also causes inflammation and pathological tissue remodeling in autoimmunity. Hence, TH17 cell differentiation and IL-17 production must be tightly regulated, but, to date, this has been defined only in terms of transcriptional control. Phosphatidylinositols are second messengers produced during T cell activation that transduce signals from the T cell receptor (TCR) and costimulatory receptors at the plasma membrane. Here, we found that phosphatidylinositol 4,5-bisphosphate (PIP2) was enriched in the nuclei of human TH17 cells, which depended on the kinase PIP5K1α, and that inhibition of PIP5K1α impaired IL-17A production. In contrast, nuclear PIP2 enrichment was not observed in TH1 or TH2 cells, and these cells did not require PIP5K1α for cytokine production. In T cells from people with multiple sclerosis, IL-17 production elicited by myelin basic protein was blocked by PIP5K1α inhibition. IL-17 protein was affected without altering either the abundance or stability of IL17A mRNA in TH17 cells. Instead, analysis of PIP5K1α-associating proteins revealed that PIP5K1α interacted with ARS2, a nuclear cap-binding complex scaffold protein, to facilitate its binding to IL17A mRNA and subsequent IL-17A protein production. These findings highlight a transcription-independent, translation-dependent mechanism for regulating IL-17A protein production that might be relevant to other cytokines.
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Affiliation(s)
- Shankar K. Revu
- Division of Rheumatology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Wenjuan Yang
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14850, USA
| | | | - Alexander Brady
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14850, USA
| | - Saikat Majumder
- Division of Rheumatology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Sarah L. Gaffen
- Division of Rheumatology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - William Hawse
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Zongqi Xia
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15261 USA
| | - Mandy J. McGeachy
- Division of Rheumatology, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
- Department of Microbiology and Immunology, Cornell University, Ithaca, NY 14850, USA
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Logue MJE, Farquhar RE, Eckhoff-Björngard Y, Cheung TT, Devor DC, McDonald FJ, Hamilton KL. The exocyst complex is required for the trafficking and delivery of KCa3.1 to the basolateral membrane of polarized epithelia. Am J Physiol Cell Physiol 2023; 324:C1249-C1262. [PMID: 37125772 PMCID: PMC10243536 DOI: 10.1152/ajpcell.00374.2022] [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: 08/17/2022] [Revised: 04/19/2023] [Accepted: 04/19/2023] [Indexed: 05/02/2023]
Abstract
Control of the movement of ions and water across epithelia is essential for homeostasis. Changing the number or activity of ion channels at the plasma membrane is a significant regulator of epithelial transport. In polarized epithelia, the intermediate-conductance calcium-activated potassium channel, KCa3.1 is delivered to the basolateral membrane where it generates and maintains the electrochemical gradients required for epithelial transport. The mechanisms that control the delivery of KCa3.1 to the basolateral membrane are still emerging. Herein, we investigated the role of the highly conserved tethering complex exocyst. In epithelia, exocyst is involved in the tethering of post-Golgi secretory vesicles with the basolateral membrane, which is required before membrane fusion. In our Fisher rat thyroid cell line that stably expresses KCa3.1, siRNA knockdown of either of the exocyst subunits Sec3, Sec6, or Sec8 significantly decreased KCa3.1-specific current. In addition, knockdown of exocyst complex subunits significantly reduced the basolateral membrane protein level of KCa3.1. Finally, co-immunoprecipitation experiments suggest associations between Sec6 and KCa3.1, but not between Sec8 and KCa3.1. Collectively, based on these data and our previous studies, we suggest that components of exocyst complex are crucially important in the tethering of KCa3.1 to the basolateral membrane. After which, Soluble N-ethylmaleimide-sensitive factor (SNF) Attachment Receptors (SNARE) proteins aid in the insertion of KCa3.1-containing vesicles into the basolateral membrane of polarized epithelia.NEW & NOTEWORTHY Our Ussing chamber and immunoblot experiments demonstrate that when subunits of the exocyst complex were transiently knocked down, this significantly reduced the basolateral population and functional expression of KCa3.1. These data suggest, combined with our protein association experiments, that the exocyst complex regulates the tethering of KCa3.1-containing vesicles to the basolateral membrane prior to the SNARE-dependent insertion of channels into the basolateral membrane of epithelial cells.
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Affiliation(s)
- Matthew J E Logue
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Rachel E Farquhar
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Yoakim Eckhoff-Björngard
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Tanya T Cheung
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Daniel C Devor
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Fiona J McDonald
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Kirk L Hamilton
- Department of Physiology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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Bura A, Čabrijan S, Đurić I, Bruketa T, Jurak Begonja A. A Plethora of Functions Condensed into Tiny Phospholipids: The Story of PI4P and PI(4,5)P 2. Cells 2023; 12:1411. [PMID: 37408244 DOI: 10.3390/cells12101411] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 07/07/2023] Open
Abstract
Phosphoinositides (PIs) are small, phosphorylated lipids that serve many functions in the cell. They regulate endo- and exocytosis, vesicular trafficking, actin reorganization, and cell mobility, and they act as signaling molecules. The most abundant PIs in the cell are phosphatidylinositol-4-monophosphate (PI4P) and phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. PI4P is mostly localized at the Golgi apparatus where it regulates the anterograde trafficking from the Golgi apparatus to the plasma membrane (PM), but it also localizes at the PM. On the other hand, the main localization site of PI(4,5)P2 is the PM where it regulates the formation of endocytic vesicles. The levels of PIs are regulated by many kinases and phosphatases. Four main kinases phosphorylate the precursor molecule phosphatidylinositol into PI4P, divided into two classes (PI4KIIα, PI4KIIβ, PI4KIIIα, and PI4KIIIβ), and three main kinases phosphorylate PI4P to form PI(4,5)P2 (PI4P5KIα, PI4P5KIβ, and PI4P5KIγ). In this review, we discuss the localization and function of the kinases that produce PI4P and PI(4,5)P2, as well as the localization and function of their product molecules with an overview of tools for the detection of these PIs.
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Affiliation(s)
- Ana Bura
- Laboratory of Hematopoiesis, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia
| | - Sara Čabrijan
- Laboratory of Hematopoiesis, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia
| | - Iris Đurić
- Laboratory of Hematopoiesis, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia
| | - Tea Bruketa
- Laboratory of Hematopoiesis, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia
| | - Antonija Jurak Begonja
- Laboratory of Hematopoiesis, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia
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10
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Weston E, Pangilinan F, Eaton S, Orford M, Leung KY, Copp AJ, Mills JL, Molloy AM, Brody LC, Greene NDE. Investigating Genetic Determinants of Plasma Inositol Status in Adult Humans. J Nutr 2022; 152:2333-2342. [PMID: 36774100 PMCID: PMC9644178 DOI: 10.1093/jn/nxac204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/02/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Myo-inositol (MI) is incorporated into numerous biomolecules, including phosphoinositides and inositol phosphates. Disturbance of inositol availability or metabolism is associated with various disorders, including neurological conditions and cancers, whereas supplemental MI has therapeutic potential in conditions such as depression, polycystic ovary syndrome, and congenital anomalies. Inositol status can be influenced by diet, synthesis, transport, utilization, and catabolism. OBJECTIVES We aimed to investigate potential genetic regulation of circulating MI status and to evaluate correlation of MI concentration with other metabolites. METHODS GC-MS was used to determine plasma MI concentration of >2000 healthy, young adults (aged 18-28 y) from the Trinity Student Study. Genotyping data were used to test association of plasma MI with single nucleotide polymorphisms (SNPs) in candidate genes, encoding inositol transporters and synthesizing enzymes, and test for genome-wide association. We evaluated potential correlation of plasma MI with d-chiro-inositol (DCI), glucose, and other metabolites by Spearman rank correlation. RESULTS Mean plasma MI showed a small but significant difference between males and females (28.5 and 26.9 μM, respectively). Candidate gene analysis revealed several nominally significant associations with plasma MI, most notably for SLC5A11 (solute carrier family 5 member 11), encoding a sodium-coupled inositol transporter, also known as SMIT2 (sodium-dependent myo-inositol transporter 2). However, these did not survive correction for multiple testing. Subsequent testing for genome-wide association with plasma MI did not identify associations of genome-wide significance (P < 5 × 10-8). However, 8 SNPs exceeded the threshold for suggestive significant association with plasma MI concentration (P < 1 × 10-5), 3 of which were located within or close to genes: MTDH (metadherin), LAPTM4B (lysosomal protein transmembrane 4 β), and ZP2 (zona pellucida 2). We found significant positive correlation of plasma MI concentration with concentration of dci and several other biochemicals including glucose, methionine, betaine, sarcosine, and tryptophan. CONCLUSIONS Our findings suggest potential for modulation of plasma MI in young adults by variation in SLC5A11, which is worthy of further investigation.
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Affiliation(s)
- Eleanor Weston
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Faith Pangilinan
- Genetics and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Simon Eaton
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Michael Orford
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Kit-Yi Leung
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Andrew J Copp
- Developmental Biology and Cancer Department, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - James L Mills
- Epidemiology Branch, Division of Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Anne M Molloy
- Department of Clinical Medicine, School of Medicine, Trinity College, Dublin, Ireland
| | - Lawrence C Brody
- Genetics and Environment Interaction Section, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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11
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Wolff DW, Bianchi-Smiraglia A, Nikiforov MA. Compartmentalization and regulation of GTP in control of cellular phenotypes. Trends Mol Med 2022; 28:758-769. [PMID: 35718686 PMCID: PMC9420775 DOI: 10.1016/j.molmed.2022.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 10/18/2022]
Abstract
Genetic or pharmacological inhibition of enzymes involved in GTP biosynthesis has substantial biological effects, underlining the need to better understand the function of GTP levels in regulation of cellular processes and the significance of targeting GTP biosynthesis enzymes for therapeutic intervention. Our current understanding of spatiotemporal regulation of GTP metabolism and its role in physiological and pathological cellular processes is far from complete. Novel methodologies such as genetically encoded sensors of free GTP offered insights into intracellular distribution and function of GTP molecules. In the current Review, we provide analysis of recent discoveries in the field of GTP metabolism and evaluate the key enzymes as molecular targets.
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Affiliation(s)
- David W Wolff
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA.
| | - Anna Bianchi-Smiraglia
- Department of Cell Stress Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, USA
| | - Mikhail A Nikiforov
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC 27708, USA; Department of Pathology, Duke University School of Medicine, Durham, NC 27710, USA.
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12
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Watari M, Kato M, Blanc-Mathieu R, Tsuge T, Ogata H, Aoyama T. Functional Differentiation among the Arabidopsis Phosphatidylinositol 4-Phosphate 5-Kinase Genes PIP5K1, PIP5K2 and PIP5K3. PLANT & CELL PHYSIOLOGY 2022; 63:635-648. [PMID: 35348769 DOI: 10.1093/pcp/pcac025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/16/2022] [Accepted: 02/20/2022] [Indexed: 06/14/2023]
Abstract
Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) is involved in regulating various cellular processes through the signaling function of its product, phosphatidylinositol (4,5)-bisphosphate. Higher plants encode a large number of PIP5Ks forming distinct clades in their molecular phylogenetic tree. Although biological functions of PIP5K genes have been analyzed intensively in Arabidopsis thaliana, it remains unclear how those functions differ across clades of paralogs. We performed comparative functional analysis of the Arabidopsis genes encoding PIP5K1, PIP5K2 and PIP5K3, of which the first two and the last belong to closely related but distinct clades, to clarify their conserved and/or differentiated functions. Genetic analysis with their single and multiple mutants revealed that PIP5K1 and PIP5K3 have non-overlapping functions, with the former in total plant growth and the latter in root hair elongation, whereas PIP5K2 redundantly functions in both phenomena. This pattern of functional redundancy is explainable in terms of the overlapping pattern of their promoter activities. In transformation rescue experiments, PIP5K3 promoter-directed PIP5K1-YFP completely rescued the short-root-hair phenotype of pip5k3. However, PIP5K3-YFP could substitute for PIP5K1-YFP only partially in rescuing the severe dwarfism of pip5k1pip5k2 when directed by the PIP5K1 promoter. Phylogenetic analysis of angiosperm PIP5Ks revealed that PIP5K3 orthologs have a faster rate of diversification in their amino-acid sequences compared with PIP5K1/2 orthologs after they arose through a eudicot-specific duplication event. These findings suggest that PIP5K3 specialized to promote root hair elongation and lost some of the protein-encoded functions retained by PIP5K1 and PIP5K2, whereas PIP5K1 differentiated from PIP5K2 only in its promoter-directed expression pattern.
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Affiliation(s)
- Machiko Watari
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
| | - Mariko Kato
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
| | - Romain Blanc-Mathieu
- Laboratoire Physiologie Cellulaire & Vegetale, University of Grenoble Alpes, IRIG, INRA, CNRS, CEA, F-38054, Grenoble 9, France
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
| | - Hiroyuki Ogata
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
| | - Takashi Aoyama
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
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13
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Arora GK, Palamiuc L, Emerling BM. Expanding role of PI5P4Ks in cancer: A promising druggable target. FEBS Lett 2022; 596:3-16. [PMID: 34822164 PMCID: PMC9154051 DOI: 10.1002/1873-3468.14237] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/04/2021] [Accepted: 11/15/2021] [Indexed: 12/14/2022]
Abstract
Cancer cells are challenged by a myriad of microenvironmental stresses, and it is their ability to efficiently adapt to the constantly changing nutrient, energy, oxidative, and/or immune landscape that allows them to survive and proliferate. Such adaptations, however, result in distinct vulnerabilities that are attractive therapeutic targets. Phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) are a family of druggable stress-regulated phosphoinositide kinases that become conditionally essential as a metabolic adaptation, paving the way to targeting cancer cell dependencies. Further, PI5P4Ks have a synthetic lethal interaction with the tumor suppressor p53, the loss of which is one of the most prevalent genetic drivers of malignant transformation. PI5P4K's emergence as a crucial axis in the expanding landscape of phosphoinositide signaling in cancer has already stimulated the development of specific inhibitors. Thus, a better understanding of the biology of the PI5P4Ks will allow for targeted and effective therapeutic interventions. Here, we attempt to summarize the mounting roles of the PI5P4Ks in cancer, including evidence that targeting them is a therapeutic vulnerability and promising next-in-line treatment for multiple cancer subtypes.
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Affiliation(s)
- Gurpreet K Arora
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, USA
| | - Lavinia Palamiuc
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, USA
| | - Brooke M Emerling
- Cell and Molecular Biology of Cancer Program, Sanford Burnham Prebys, La Jolla, CA, USA
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14
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Andrews DM, Cartic S, Cosulich S, Divecha N, Faulder P, Flemington V, Kern O, Kettle JG, MacDonald E, McKelvie J, Pike KG, Roberts B, Rowlinson R, Smith JM, Stockley M, Swarbrick ME, Treinies I, Waring MJ. Identification and optimization of a novel series of selective PIP5K inhibitors. Bioorg Med Chem 2021; 54:116557. [PMID: 34922306 DOI: 10.1016/j.bmc.2021.116557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 11/02/2022]
Abstract
Phosphatidyl inositol (4,5)-bisphosphate (PI(4,5)P2) plays several key roles in human biology and the lipid kinase that produces PI(4,5)P2, PIP5K, has been hypothesized to provide a potential therapeutic target of interest in the treatment of cancers. To better understand and explore the role of PIP5K in human cancers there remains an urgent need for potent and specific PIP5K inhibitor molecules. Following a high throughput screen of the AstraZeneca collection, a novel, moderately potent and selective inhibitor of PIP5K, 1, was discovered. Detailed exploration of the SAR for this novel scaffold resulted in the considerable optimization of both potency for PIP5K, and selectivity over the closely related kinase PI3Kα, as well as identifying several opportunities for the continued optimization of drug-like properties. As a result, several high quality in vitro tool compounds were identified (8, 20 and 25) that demonstrate the desired biochemical and cellular profiles required to aid better understanding of this complex area of biology.
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Affiliation(s)
- David M Andrews
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
| | - Sharon Cartic
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Sabina Cosulich
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
| | - Nullin Divecha
- Inositide Laboratory, School of Biological Sciences, Faculty of Environmental and Life Sciences, Life Sciences Building 85, University of Southampton, Highfield Campus, Southampton, SO17 1BJ, UK
| | - Paul Faulder
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
| | - Vikki Flemington
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
| | - Oliver Kern
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Jason G Kettle
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
| | - Ellen MacDonald
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Jennifer McKelvie
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Kurt G Pike
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
| | - Bryan Roberts
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
| | - Rachel Rowlinson
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
| | - James M Smith
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK.
| | - Martin Stockley
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Martin E Swarbrick
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Iris Treinies
- Cancer Research UK Therapeutic Discovery Laboratories, Jonas Webb Building, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Michael J Waring
- Medicinal Chemistry, Oncology R&D, Research and Early Development, AstraZeneca, Cambridge Science Park, Unit 310 Darwin Building, Cambridge CB4 0WG, UK
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15
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Quantitative FRET Microscopy Reveals a Crucial Role of Cytoskeleton in Promoting PI(4,5)P 2 Confinement. Int J Mol Sci 2021; 22:ijms222111727. [PMID: 34769158 PMCID: PMC8583820 DOI: 10.3390/ijms222111727] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/24/2021] [Accepted: 10/26/2021] [Indexed: 01/30/2023] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is an essential plasma membrane component involved in several cellular functions, including membrane trafficking and cytoskeleton organization. This function multiplicity is partially achieved through a dynamic spatiotemporal organization of PI(4,5)P2 within the membrane. Here, we use a Förster resonance energy transfer (FRET) approach to quantitatively assess the extent of PI(4,5)P2 confinement within the plasma membrane. This methodology relies on the rigorous evaluation of the dependence of absolute FRET efficiencies between pleckstrin homology domains (PHPLCδ) fused with fluorescent proteins and their average fluorescence intensity at the membrane. PI(4,5)P2 is found to be significantly compartmentalized at the plasma membrane of HeLa cells, and these clusters are not cholesterol-dependent, suggesting that membrane rafts are not involved in the formation of these nanodomains. On the other hand, upon inhibition of actin polymerization, compartmentalization of PI(4,5)P2 is almost entirely eliminated, showing that the cytoskeleton network is the critical component responsible for the formation of nanoscale PI(4,5)P2 domains in HeLa cells.
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16
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Shang P, Stepicheva N, Teel K, McCauley A, Fitting CS, Hose S, Grebe R, Yazdankhah M, Ghosh S, Liu H, Strizhakova A, Weiss J, Bhutto IA, Lutty GA, Jayagopal A, Qian J, Sahel JA, Samuel Zigler J, Handa JT, Sergeev Y, Rajala RVS, Watkins S, Sinha D. βA3/A1-crystallin regulates apical polarity and EGFR endocytosis in retinal pigmented epithelial cells. Commun Biol 2021; 4:850. [PMID: 34239035 PMCID: PMC8266859 DOI: 10.1038/s42003-021-02386-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 06/24/2021] [Indexed: 12/20/2022] Open
Abstract
The retinal pigmented epithelium (RPE) is a monolayer of multifunctional cells located at the back of the eye. High membrane turnover and polarization, including formation of actin-based apical microvilli, are essential for RPE function and retinal health. Herein, we demonstrate an important role for βA3/A1-crystallin in RPE. βA3/A1-crystallin deficiency leads to clathrin-mediated epidermal growth factor receptor (EGFR) endocytosis abnormalities and actin network disruption at the apical side that result in RPE polarity disruption and degeneration. We found that βA3/A1-crystallin binds to phosphatidylinositol transfer protein (PITPβ) and that βA3/A1-crystallin deficiency diminishes phosphatidylinositol 4,5-biphosphate (PI(4,5)P2), thus probably decreasing ezrin phosphorylation, EGFR activation, internalization, and degradation. We propose that βA3/A1-crystallin acquired its RPE function before evolving as a structural element in the lens, and that in the RPE, it modulates the PI(4,5)P2 pool through PITPβ/PLC signaling axis, coordinates EGFR activation, regulates ezrin phosphorylation and ultimately the cell polarity.
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Affiliation(s)
- Peng Shang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Nadezda Stepicheva
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Kenneth Teel
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Austin McCauley
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | | | - Stacey Hose
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Rhonda Grebe
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Meysam Yazdankhah
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sayan Ghosh
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Haitao Liu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Anastasia Strizhakova
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Joseph Weiss
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Imran A Bhutto
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gerard A Lutty
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Jiang Qian
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - José-Alain Sahel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Institut de la Vision, INSERM, CNRS, Sorbonne Université, Paris, France
| | - J Samuel Zigler
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - James T Handa
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yuri Sergeev
- National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Raju V S Rajala
- Dean McGee Eye Institute, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Simon Watkins
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Department of Cell Biology and Center for Biologic Imaging, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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17
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Kuroda R, Kato M, Tsuge T, Aoyama T. Arabidopsis phosphatidylinositol 4-phosphate 5-kinase genes PIP5K7, PIP5K8, and PIP5K9 are redundantly involved in root growth adaptation to osmotic stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:913-927. [PMID: 33606325 DOI: 10.1111/tpj.15207] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
Phosphatidylinositol 4-phosphate 5-kinase (PIP5K) produces phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2 ), a signaling phospholipid critical for various cellular processes in eukaryotes. The Arabidopsis thaliana genome encodes 11 PIP5K genes. Of these, three type B PIP5K genes, PIP5K7, PIP5K8, and PIP5K9, constitute a subgroup highly conserved in land plants, suggesting that they retain a critical function shared by land plants. In this study, we comprehensively investigated the biological functions of the PIP5K7-9 subgroup genes. Reporter gene analyses revealed their preferential expression in meristematic and vascular tissues. Their YFP-fusion proteins localized primarily to the plasma membrane in root meristem epidermal cells. We selected a mutant line that was considered to be null for each gene. Under normal growth conditions, neither single mutants nor multiple mutants of any combination exhibited noticeable phenotypic changes. However, stress conditions with mannitol or NaCl suppressed main root growth and reduced proximal root meristem size to a greater extent in the pip5k7pip5k8pip5k9 triple mutant than in the wild type. In root meristem epidermal cells of the triple mutant, where plasma membrane localization of the PtdIns(4,5)P2 marker P24Y is impaired to a large extent, brefeldin A body formation is retarded compared with the wild type under hyperosmotic stress. These results indicate that PIP5K7, PIP5K8, and PIP5K9 are not required under normal growth conditions, but are redundantly involved in root growth adaptation to hyperosmotic conditions, possibly through the PtdIns(4,5)P2 function promoting plasma membrane recycling in root meristem cells.
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Affiliation(s)
- Ryo Kuroda
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
| | - Mariko Kato
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
| | - Takashi Aoyama
- Institute for Chemical Research, Kyoto University, Kyoto, 611-0011, Japan
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18
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Participation of ABCA1 Transporter in Pathogenesis of Chronic Obstructive Pulmonary Disease. Int J Mol Sci 2021; 22:ijms22073334. [PMID: 33805156 PMCID: PMC8037621 DOI: 10.3390/ijms22073334] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/19/2021] [Accepted: 03/22/2021] [Indexed: 12/12/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is the important medical and social problem. According to modern concepts, COPD is a chronic inflammatory disease, macrophages play a key role in its pathogenesis. Macrophages are heterogeneous in their functions, which is largely determined by their immunometabolic profile, as well as the features of lipid homeostasis, in which the ATP binding cassette transporter A1 (ABCA1) plays an essential role. The objective of this work is the analysis of the ABCA1 protein participation and the function of reverse cholesterol transport in the pathogenesis of COPD. The expression of the ABCA1 gene in lung tissues takes the second place after the liver, which indicates the important role of the carrier in lung function. The participation of the transporter in the development of COPD consists in provision of lipid metabolism, regulation of inflammation, phagocytosis, and apoptosis. Violation of the processes in which ABCA1 is involved may be a part of the pathophysiological mechanisms, leading to the formation of a heterogeneous clinical course of the disease.
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19
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Raghu P. Emerging cell biological functions of phosphatidylinositol 5 phosphate 4 kinase. Curr Opin Cell Biol 2021; 71:15-20. [PMID: 33677148 DOI: 10.1016/j.ceb.2021.01.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/19/2021] [Accepted: 01/30/2021] [Indexed: 12/22/2022]
Abstract
The generation of phosphoinositides (PIs) with spatial and temporal control is a key mechanism in cellular organization and signaling. The synthesis of PIs is mediated by PI kinases, proteins that are able to phosphorylate unique substrates at specific positions on the inositol headgroup to generate signaling molecules. Phosphatidylinositol 5 phosphate 4 kinase (PIP4K) is one such lipid kinase that is able to specifically phosphorylate phosphatidylinositol 5 phosphate, the most recently discovered PI to generate the well-known and abundant PI, phosphatidylinositol 4,5 bisphosphate [PI(4,5)P2]. PIP4K appears to be encoded only in metazoan genomes, and several genetic studies indicate important physiological functions for these enzymes in metabolism, immune function, and growth control. PIP4K has recently been reported to localize to multiple cellular compartments, including the nucleus, plasma membrane, endosomal systems, and autophagosome. However, the biochemical activity of these enzymes that is relevant to these physiological functions remains elusive. We review recent developments in this area and highlight emerging roles for these enzymes in cellular organization.
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Affiliation(s)
- Padinjat Raghu
- Cellular Organization and Signaling, National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore, 560065, India.
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20
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Role of protons in calcium signaling. Biochem J 2021; 478:895-910. [PMID: 33635336 DOI: 10.1042/bcj20200971] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 02/03/2023]
Abstract
Thirty-six years after the publication of the important article by Busa and Nuccitelli on the variability of intracellular pH (pHi) and the interdependence of pHi and intracellular Ca2+ concentration ([Ca2+]i), little research has been carried out on pHi and calcium signaling. Moreover, the results appear to be contradictory. Some authors claim that the increase in [Ca2+]i is due to a reduction in pHi, others that it is caused by an increase in pHi. The reasons for these conflicting results have not yet been discussed and clarified in an exhaustive manner. The idea that variations in pHi are insignificant, because cellular buffers quickly stabilize the pHi, may be a limiting and fundamentally wrong concept. In fact, it has been shown that protons can move and react in the cell before they are neutralized. Variations in pHi have a remarkable impact on [Ca2+]i and hence on some of the basic biochemical mechanisms of calcium signaling. This paper focuses on the possible triggering role of protons during their short cellular cycle and it suggests a new hypothesis for an IP3 proton dependent mechanism of action.
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21
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Targeting SHIP1 and SHIP2 in Cancer. Cancers (Basel) 2021; 13:cancers13040890. [PMID: 33672717 PMCID: PMC7924360 DOI: 10.3390/cancers13040890] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 02/12/2021] [Accepted: 02/13/2021] [Indexed: 12/31/2022] Open
Abstract
Simple Summary Phosphoinositol signaling pathways and their dysregulation have been shown to have a fundamental role in health and disease, respectively. The SH2-containing 5′ inositol phosphatases, SHIP1 and SHIP2, are regulators of the PI3K/AKT pathway that have crucial roles in cancer progression. This review aims to summarize the role of SHIP1 and SHIP2 in cancer signaling and the immune response to cancer, the discovery and use of SHIP inhibitors and agonists as possible cancer therapeutics. Abstract Membrane-anchored and soluble inositol phospholipid species are critical mediators of intracellular cell signaling cascades. Alterations in their normal production or degradation are implicated in the pathology of a number of disorders including cancer and pro-inflammatory conditions. The SH2-containing 5′ inositol phosphatases, SHIP1 and SHIP2, play a fundamental role in these processes by depleting PI(3,4,5)P3, but also by producing PI(3,4)P2 at the inner leaflet of the plasma membrane. With the intent of targeting SHIP1 or SHIP2 selectively, or both paralogs simultaneously, small molecule inhibitors and agonists have been developed and tested in vitro and in vivo over the last decade in various disease models. These studies have shown promising results in various pre-clinical models of disease including cancer and tumor immunotherapy. In this review the potential use of SHIP inhibitors in cancer is discussed with particular attention to the molecular structure, binding site and efficacy of these SHIP inhibitors.
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Wen Y, Vogt VM, Feigenson GW. PI(4,5)P 2 Clustering and Its Impact on Biological Functions. Annu Rev Biochem 2021; 90:681-707. [PMID: 33441034 DOI: 10.1146/annurev-biochem-070920-094827] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Located at the inner leaflet of the plasma membrane (PM), phosphatidyl-inositol 4,5-bisphosphate [PI(4,5)P2] composes only 1-2 mol% of total PM lipids. With its synthesis and turnover both spatially and temporally regulated, PI(4,5)P2 recruits and interacts with hundreds of cellular proteins to support a broad spectrum of cellular functions. Several factors contribute to the versatile and dynamic distribution of PI(4,5)P2 in membranes. Physiological multivalent cations such as Ca2+ and Mg2+ can bridge between PI(4,5)P2 headgroups, forming nanoscopic PI(4,5)P2-cation clusters. The distinct lipid environment surrounding PI(4,5)P2 affects the degree of PI(4,5)P2 clustering. In addition, diverse cellular proteins interacting with PI(4,5)P2 can further regulate PI(4,5)P2 lateral distribution and accessibility. This review summarizes the current understanding of PI(4,5)P2 behavior in both cells and model membranes, with emphasis on both multivalent cation- and protein-induced PI(4,5)P2 clustering. Understanding the nature of spatially separated pools of PI(4,5)P2 is fundamental to cell biology.
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Affiliation(s)
- Yi Wen
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA; , ,
| | - Volker M Vogt
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA; , ,
| | - Gerald W Feigenson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA; , ,
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Phosphatidylinositol-3-OH kinase signalling is spatially organized at endosomal compartments by microtubule-associated protein 4. Nat Cell Biol 2020; 22:1357-1370. [PMID: 33139939 DOI: 10.1038/s41556-020-00596-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/24/2020] [Indexed: 12/20/2022]
Abstract
The canonical model of agonist-stimulated phosphatidylinositol-3-OH kinase (PI3K)-Akt signalling proposes that PI3K is activated at the plasma membrane, where receptors are activated and phosphatidylinositol-4,5-bisphosphate is concentrated. Here we show that phosphatidylinositol-3,4,5-trisphosphate generation and activated Akt are instead largely confined to intracellular membranes upon receptor tyrosine kinase activation. Microtubule-associated protein 4 (MAP4) interacts with and controls localization of membrane vesicle-associated PI3Kα to microtubules. The microtubule-binding domain of MAP4 binds directly to the C2 domain of the p110α catalytic subunit. MAP4 controls the interaction of PI3Kα with activated receptors at endosomal compartments along microtubules. Loss of MAP4 results in the loss of PI3Kα targeting and loss of PI3K-Akt signalling downstream of multiple agonists. The MAP4-PI3Kα assembly defines a mechanism for spatial control of agonist-stimulated PI3K-Akt signalling at internal membrane compartments linked to the microtubule network.
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Li S, Ghosh C, Xing Y, Sun Y. Phosphatidylinositol 4,5-bisphosphate in the Control of Membrane Trafficking. Int J Biol Sci 2020; 16:2761-2774. [PMID: 33061794 PMCID: PMC7545710 DOI: 10.7150/ijbs.49665] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/14/2020] [Indexed: 12/15/2022] Open
Abstract
Phosphoinositides are membrane lipids generated by phosphorylation on the inositol head group of phosphatidylinositol. By specifically distributed to distinct subcellular membrane locations, different phosphoinositide species play diverse roles in modulating membrane trafficking. Among the seven known phosphoinositide species, phosphatidylinositol 4,5-bisphosphate (PI4,5P2) is the one species most abundant at the plasma membrane. Thus, the PI4,5P2 function in membrane trafficking is first identified in controlling plasma membrane dynamic-related events including endocytosis and exocytosis. However, recent studies indicate that PI4,5P2 is also critical in many other membrane trafficking events such as endosomal trafficking, hydrolases sorting to lysosomes, autophagy initiation, and autophagic lysosome reformation. These findings suggest that the role of PI4,5P2 in membrane trafficking is far beyond just plasma membrane. This review will provide a concise synopsis of how PI4,5P2 functions in multiple membrane trafficking events. PI4,5P2, the enzymes responsible for PI4,5P2 production at specific subcellular locations, and distinct PI4,5P2 effector proteins compose a regulation network to control the specific membrane trafficking events.
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Affiliation(s)
- Suhua Li
- Philips Institute for Oral Health Research, School of Dentistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Chinmoy Ghosh
- Philips Institute for Oral Health Research, School of Dentistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Yanli Xing
- Department of Otolaryngology, Shanghai Pudong New Area Gongli Hospital, Shanghai, China
| | - Yue Sun
- Philips Institute for Oral Health Research, School of Dentistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA 23298, USA
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Rendezvous at Plasma Membrane: Cellular Lipids and tRNA Set up Sites of HIV-1 Particle Assembly and Incorporation of Host Transmembrane Proteins. Viruses 2020; 12:v12080842. [PMID: 32752131 PMCID: PMC7472227 DOI: 10.3390/v12080842] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 12/28/2022] Open
Abstract
The HIV-1 structural polyprotein Gag drives the virus particle assembly specifically at the plasma membrane (PM). During this process, the nascent virion incorporates specific subsets of cellular lipids and host membrane proteins, in addition to viral glycoproteins and viral genomic RNA. Gag binding to the PM is regulated by cellular factors, including PM-specific phospholipid PI(4,5)P2 and tRNAs, both of which bind the highly basic region in the matrix domain of Gag. In this article, we review our current understanding of the roles played by cellular lipids and tRNAs in specific localization of HIV-1 Gag to the PM. Furthermore, we examine the effects of PM-bound Gag on the organization of the PM bilayer and discuss how the reorganization of the PM at the virus assembly site potentially contributes to the enrichment of host transmembrane proteins in the HIV-1 particle. Since some of these host transmembrane proteins alter release, attachment, or infectivity of the nascent virions, the mechanism of Gag targeting to the PM and the nature of virus assembly sites have major implications in virus spread.
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Abstract
Profilin is a ubiquitously expressed protein well known as a key regulator of actin polymerisation. The actin cytoskeleton is involved in almost all cellular processes including motility, endocytosis, metabolism, signal transduction and gene transcription. Hence, profilin's role in the cell goes beyond its direct and essential function in regulating actin dynamics. This review will focus on the interactions of Profilin 1 and its ligands at the plasma membrane, in the cytoplasm and the nucleus of the cells and the regulation of profilin activity within those cell compartments. We will discuss the interactions of profilin in cell signalling pathways and highlight the importance of the cell context in the multiple functions that this small essential protein has in conjunction with its role in cytoskeletal organisation and dynamics. We will review some of the mechanisms that control profilin expression and the implications of changed expression of profilin in the light of cancer biology and other pathologies.
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27
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Wang DG, Paddock MN, Lundquist MR, Sun JY, Mashadova O, Amadiume S, Bumpus TW, Hodakoski C, Hopkins BD, Fine M, Hill A, Yang TJ, Baskin JM, Dow LE, Cantley LC. PIP4Ks Suppress Insulin Signaling through a Catalytic-Independent Mechanism. Cell Rep 2020; 27:1991-2001.e5. [PMID: 31091439 PMCID: PMC6619495 DOI: 10.1016/j.celrep.2019.04.070] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 02/06/2019] [Accepted: 04/16/2019] [Indexed: 12/17/2022] Open
Abstract
Insulin stimulates the conversion of phosphatidylino-sitol-4,5-bisphosphate (PI(4,5)P2) to phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3), which mediates downstream cellular responses. PI(4,5)P2 is produced by phosphatidylinositol-4-phosphate 5-kinases (PIP5Ks) and by phosphatidylinositol-5-phos-phate 4-kinases (PIP4Ks). Here, we show that the loss of PIP4Ks (PIP4K2A, PIP4K2B, and PIP4K2C) in vitro results in a paradoxical increase in PI(4,5)P2 and a concomitant increase in insulin-stimulated production of PI(3,4,5)P3. The reintroduction of either wild-type or kinase-dead mutants of the PIP4Ks restored cellular PI(4,5)P2 levels and insulin stimulation of the PI3K pathway, suggesting a catalytic-independent role of PIP4Ks in regulating PI(4,5)P2 levels. These effects are explained by an increase in PIP5K activity upon the deletion of PIP4Ks, which normally suppresses PIP5K activity through a direct binding interaction mediated by the N-terminal motif VMLϕFPDD of PIP4K. Our work uncovers an allosteric function of PIP4Ks in suppressing PIP5K-mediated PI(4,5)P2 synthesis and insulin-dependent conversion to PI(3,4,5)P3 and suggests that the pharmacological depletion of PIP4K enzymes could represent a strategy for enhancing insulin signaling. PI(4,5)P2 is produced by both phosphatidylinositol-4-phosphate 5-kinases (PIP5Ks) and by phosphatidylinositol-5-phosphate 4-kinases (PIP4Ks). Wang et al. report an allosteric function of a conserved N-terminal motif of PIP4Ks in suppressing PIP5K-mediated PI(4,5)P2 synthesis and insulin-dependent conversion to PI(3,4,5) P3. This non-catalytic role has implications for the development of PIP4K targeted therapies.
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Affiliation(s)
- Diana G Wang
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Weill Cornell Medicine/Rockefeller University/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA
| | - Marcia N Paddock
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Hematology and Oncology Division, Department of Medicine, Weill Cornell Medicine, New York, NY 10021, USA
| | - Mark R Lundquist
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Janet Y Sun
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Oksana Mashadova
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Solomon Amadiume
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Timothy W Bumpus
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Cindy Hodakoski
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | | | - Matthew Fine
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - Amanda Hill
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA
| | - T Jonathan Yang
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Jeremy M Baskin
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Lukas E Dow
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA; Hematology and Oncology Division, Department of Medicine, Weill Cornell Medicine, New York, NY 10021, USA; Department of Biochemistry, Weill Cornell Medicine, New York, NY 10021, USA
| | - Lewis C Cantley
- Meyer Cancer Center, Weill Cornell Medicine, New York, NY 10021, USA.
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Using Phosphatidylinositol Phosphorylation as Markers for Hyperglycemic Related Breast Cancer. Int J Mol Sci 2020; 21:ijms21072320. [PMID: 32230859 PMCID: PMC7177416 DOI: 10.3390/ijms21072320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 02/06/2023] Open
Abstract
Studies have suggested that type 2 diabetes (T2D) is associated with a higher incidence of breast cancer and related mortality rates. T2D postmenopausal women have an ~20% increased chance of developing breast cancer, and women with T2D and breast cancer have a 50% increase in mortality compared to breast cancer patients without diabetes. This correlation has been attributed to the general activation of insulin receptor signaling, glucose metabolism, phosphatidylinositol (PI) kinases, and growth pathways. Furthermore, the presence of breast cancer specific PI kinase and/or phosphatase mutations enhance metastatic breast cancer phenotypes. We hypothesized that each of the breast cancer subtypes may have characteristic PI phosphorylation profiles that are changed in T2D conditions. Therefore, we sought to characterize the PI phosphorylation when equilibrated in normal glycemic versus hyperglycemic serum conditions. Our results suggest that hyperglycemia leads to: 1) A reduction in PI3P and PIP3, with increased PI4P that is later converted to PI(3,4)P2 at the cell surface in hormone receptor positive breast cancer; 2) a reduction in PI3P and PI4P with increased PIP3 surface expression in human epidermal growth factor receptor 2-positive (HER2+) breast cancer; and 3) an increase in di- and tri-phosphorylated PIs due to turnover of PI3P in triple negative breast cancer. This study begins to describe some of the crucial changes in PIs that play a role in T2D related breast cancer incidence and metastasis.
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Wang X, Yue H, Li S, Guo J, Guan Z, Qin J, Zhu Z, Niu B, Cui M, Wang J. The Effects of Inositol Metabolism in Pregnant Women on Offspring in the North and South of China. Med Sci Monit 2020; 26:e921088. [PMID: 32063600 PMCID: PMC7041423 DOI: 10.12659/msm.921088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Background Inositol is an essential nutrient for cell growth, survival and embryonic development. Myo-inositol is the predominant form in natural. To investigate the correlation between inositol metabolism and embryonic development, we assessed the metabolic characteristics of myo-inositol, phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) and phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) of pregnant women in the North China (Yangquan and Weihai) and South China (Nanchang and Haikou) China. Material/Methods All data were collected by face-to-face interview during pregnant women health visits using a questionnaire. Plasma levels of myo-inositol, PI(4,5)P2 and PI(3,4,5)P3 from 89 randomly collected pregnant women were detected by gas chromatography-mass spectrometry and enzyme linked immunosorbent assay. Results A total of 400 pregnant women were included in this survey. The plasma levels of myo-inositol and PI(4,5)P2 in the North China group of pregnant women were significantly higher than that in the South China group (P<0.01). The birth weight of fetuses in the North China group was heavier than that in the South China group (P<0.01). The birth length of fetuses in Yangquan was the longest among the 4 cities (P<0.01). The incidence rate of birth defects was 3.05% in the North China group, and 0.0% in the South China group. In bivariate linear correlation analysis, the body weight correlated with myo-inositol (r=0.5044, P<0.0001), PI(4,5)P2 (r=0.5950, P<0.0001) and PI(3,4,5)P3 (r=0.4710, P<0.0001), the body length was correlated with PI(4,5)P2 (r=0.3114, P=0.0035) and PI(3,4,5)P3 (r=0.2638, P<0.0130). Conclusions The plasma levels of myo-inositol and PI(4,5)P2 in pregnant women had significant difference between the North and the South of China, which might be correlated with fetal development and birth defects.
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Affiliation(s)
- Xiuwei Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland)
| | - Huixuan Yue
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland).,Graduate School of Peking Union Medical College, Beijing, China (mainland)
| | - Shen Li
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland).,Graduate School of Peking Union Medical College, Beijing, China (mainland)
| | - Jin Guo
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland)
| | - Zhen Guan
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland)
| | - Jiaxing Qin
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland)
| | - Zhiqiang Zhu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland)
| | - Bo Niu
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland).,Graduate School of Peking Union Medical College, Beijing, China (mainland)
| | - Mingming Cui
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland)
| | - Jianhua Wang
- Beijing Municipal Key Laboratory of Child Development and Nutriomics, Capital Institute of Pediatrics, Beijing, China (mainland).,Graduate School of Peking Union Medical College, Beijing, China (mainland)
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30
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Pemberton JG, Kim YJ, Balla T. Integrated regulation of the phosphatidylinositol cycle and phosphoinositide-driven lipid transport at ER-PM contact sites. Traffic 2019; 21:200-219. [PMID: 31650663 DOI: 10.1111/tra.12709] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/02/2019] [Accepted: 10/16/2019] [Indexed: 12/20/2022]
Abstract
Among the structural phospholipids that form the bulk of eukaryotic cell membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the common precursor for low-abundance regulatory lipids, collectively referred to as polyphosphoinositides (PPIn). The metabolic turnover of PPIn species has received immense attention because of the essential functions of these lipids as universal regulators of membrane biology and their dysregulation in numerous human pathologies. The diverse functions of PPIn lipids occur, in part, by orchestrating the spatial organization and conformational dynamics of peripheral or integral membrane proteins within defined subcellular compartments. The emerging role of stable contact sites between adjacent membranes as specialized platforms for the coordinate control of ion exchange, cytoskeletal dynamics, and lipid transport has also revealed important new roles for PPIn species. In this review, we highlight the importance of membrane contact sites formed between the endoplasmic reticulum (ER) and plasma membrane (PM) for the integrated regulation of PPIn metabolism within the PM. Special emphasis will be placed on non-vesicular lipid transport during control of the PtdIns biosynthetic cycle as well as toward balancing the turnover of the signaling PPIn species that define PM identity.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Maryland
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Maryland
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, Maryland
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31
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Kim KW, Kim K, Lee H, Suh BC. Ethanol Elevates Excitability of Superior Cervical Ganglion Neurons by Inhibiting Kv7 Channels in a Cell Type-Specific and PI(4,5)P 2-Dependent Manner. Int J Mol Sci 2019; 20:E4419. [PMID: 31500374 PMCID: PMC6770022 DOI: 10.3390/ijms20184419] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/13/2022] Open
Abstract
Alcohol causes diverse acute and chronic symptoms that often lead to critical health problems. Exposure to ethanol alters the activities of sympathetic neurons that control the muscles, eyes, and blood vessels in the brain. Although recent studies have revealed the cellular targets of ethanol, such as ion channels, the molecular mechanism by which alcohol modulates the excitability of sympathetic neurons has not been determined. Here, we demonstrated that ethanol increased the discharge of membrane potentials in sympathetic neurons by inhibiting the M-type or Kv7 channel consisting of the Kv7.2/7.3 subunits, which were involved in determining the membrane potential and excitability of neurons. Three types of sympathetic neurons, classified by their threshold of activation and firing patterns, displayed distinct sensitivities to ethanol, which were negatively correlated with the size of the Kv7 current that differs depending on the type of neuron. Using a heterologous expression system, we further revealed that the inhibitory effects of ethanol on Kv7.2/7.3 currents were facilitated or diminished by adjusting the amount of plasma membrane phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). These results suggested that ethanol and PI(4,5)P2 modulated gating of the Kv7 channel in superior cervical ganglion neurons in an antagonistic manner, leading to regulation of the membrane potential and neuronal excitability, as well as the physiological functions mediated by sympathetic neurons.
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Affiliation(s)
- Kwon-Woo Kim
- Department of Brain and cognitive sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
| | - Keetae Kim
- Department of New biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
| | - Hyosang Lee
- Department of Brain and cognitive sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
| | - Byung-Chang Suh
- Department of Brain and cognitive sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea.
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Kato M, Tsuge T, Maeshima M, Aoyama T. Arabidopsis PCaP2 modulates the phosphatidylinositol 4,5-bisphosphate signal on the plasma membrane and attenuates root hair elongation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 99:610-625. [PMID: 30604455 DOI: 10.1111/tpj.14226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 12/12/2018] [Accepted: 12/17/2018] [Indexed: 05/22/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2 ] serves as a subcellular signal on the plasma membrane, mediating various cell-polarized phenomena including polar cell growth. Here, we investigated the involvement of Arabidopsis thaliana PCaP2, a plant-unique plasma membrane protein with phosphoinositide-binding activity, in PtdIns(4,5)P2 signaling for root hair tip growth. The long-root-hair phenotype of the pcap2 knockdown mutant was found to stem from its higher average root hair elongation rate compared with the wild type and to counteract the low average rate caused by a defect in the PtdIns(4,5)P2 -producing enzyme gene PIP5K3. On the plasma membrane of elongating root hairs, the PCaP2 promoter-driven PCaP2-green fluorescent protein (GFP), which complemented the pcap2 mutant phenotype, overlapped with the PtdIns(4,5)P2 marker 2xCHERRY-2xPHPLC in the subapical region, but not at the apex, suggesting that PCaP2 attenuates root hair elongation via PtdIns(4,5)P2 signaling on the subapical plasma membrane. Consistent with this, a GFP fusion with the PCaP2 phosphoinositide-binding domain PCaP2N23 , root hair-specific overexpression of which caused a low average root hair elongation rate, localized more intense to the subapical plasma membrane than to the apical plasma membrane similar to PCaP2-GFP. Inducibly overexpressed PCaP2-GFP, but not its derivative lacking the PCaP2N23 domain, replaced 2xCHERRY-2xPHPLC on the plasma membrane in root meristematic epidermal cells, and suppressed FM4-64 internalization in elongating root hairs. Moreover, inducibly overexpressed PCaP2 arrested an endocytic process of PIN2-GFP recycling. Based on these results, we conclude that PCaP2 functions as a negative modulator of PtdIns(4,5)P2 signaling on the subapical plasma membrane probably through competitive binding to PtdIns(4,5)P2 and attenuates root hair elongation.
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Affiliation(s)
- Mariko Kato
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Tomohiko Tsuge
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Masayoshi Maeshima
- Laboratory of Cell Dynamics, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Nagoya, Aichi, 464-8601, Japan
| | - Takashi Aoyama
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
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Bros M, Haas K, Moll L, Grabbe S. RhoA as a Key Regulator of Innate and Adaptive Immunity. Cells 2019; 8:cells8070733. [PMID: 31319592 PMCID: PMC6678964 DOI: 10.3390/cells8070733] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/04/2019] [Accepted: 07/10/2019] [Indexed: 12/13/2022] Open
Abstract
RhoA is a ubiquitously expressed cytoplasmic protein that belongs to the family of small GTPases. RhoA acts as a molecular switch that is activated in response to binding of chemokines, cytokines, and growth factors, and via mDia and the ROCK signaling cascade regulates the activation of cytoskeletal proteins, and other factors. This review aims to summarize our current knowledge on the role of RhoA as a general key regulator of immune cell differentiation and function. The contribution of RhoA for the primary functions of innate immune cell types, namely neutrophils, macrophages, and conventional dendritic cells (DC) to (i) get activated by pathogen-derived and endogenous danger signals, (ii) migrate to sites of infection and inflammation, and (iii) internalize pathogens has been fairly established. In activated DC, which constitute the most potent antigen-presenting cells of the immune system, RhoA is also important for the presentation of pathogen-derived antigen and the formation of an immunological synapse between DC and antigen-specific T cells as a prerequisite to induce adaptive T cell responses. In T cells and B cells as the effector cells of the adaptive immune system Rho signaling is pivotal for activation and migration. More recently, mutations of Rho and Rho-modulating factors have been identified to predispose for autoimmune diseases and as causative for hematopoietic malignancies.
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Affiliation(s)
- Matthias Bros
- University Medical Center Mainz, Department of Dermatology, Langenbeckstraße 1, 55131 Mainz, Germany.
| | - Katharina Haas
- University Medical Center Mainz, Department of Dermatology, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Lorna Moll
- University Medical Center Mainz, Department of Dermatology, Langenbeckstraße 1, 55131 Mainz, Germany
| | - Stephan Grabbe
- University Medical Center Mainz, Department of Dermatology, Langenbeckstraße 1, 55131 Mainz, Germany
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34
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Ni W, Li Y, Cai L, Dong C, Fang H, Chen Y, Li H, Yao M, Xiao N. SUMOylation is required for PIPK1γ-driven keratinocyte migration and growth. FEBS J 2019; 286:4709-4720. [PMID: 31276292 DOI: 10.1111/febs.14978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/11/2019] [Accepted: 07/02/2019] [Indexed: 12/13/2022]
Abstract
PIPKIγ, a key member of the type I phosphatidylinositol 4-phosphate kinase (PIPKI) family that regulates the spatial-temporal generation of PIP2, has been implicated in diverse biological processes including cell survival, cell polarity, and cell migration. An essential role of PIPKIγ in tumor cells and nerve cells has been established in previous studies. However, the function and regulatory mechanism of PIPKIγ remains incompletely understood. Here, we showed that PIPKIγ can specifically associate with the SUMO-conjugating (E2) enzyme UBC9 and can be SUMOylated both in vivo and in vitro. We further identified that Lys-591 is the critical SUMO-acceptor site of PIPKIγ and that SUMO conjugation at this site is required for PIPKIγ-driven keratinocyte migration and growth. Mechanistically, SUMOylation deficiency significantly disrupts PIPKIγ-mediated generation of intracellular PIP2, rather than the subcellular translocation and protein stability of PIPKIγ. Our findings reveal that PIPKIγ is a novel SUMOylation target and highlight the essential role of PIPKIγ SUMOylation in human keratinocyte function, providing an important orientation for in-depth study of wound repair.
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Affiliation(s)
- Wei Ni
- Cancer Institute of Traditional Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, China.,Department of Burns and Plastic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, China.,Bengbu Medical College, Anhui, China
| | - Ying Li
- Department of Emergency, Qingdao Municipal Hospital, Shandong, China
| | - Lili Cai
- Cancer Institute of Traditional Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, China
| | - Changsheng Dong
- Cancer Institute of Traditional Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, China
| | - Houshun Fang
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, China
| | - Yao Chen
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, China
| | - Hui Li
- Key Laboratory of Pediatric Hematology and Oncology, Ministry of Health and Pediatric Translational Medicine Institute, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, China
| | - Min Yao
- Department of Burns and Plastic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, China
| | - Ning Xiao
- Cancer Institute of Traditional Chinese Medicine, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, China
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Nuclear Phosphoinositides-Versatile Regulators of Genome Functions. Cells 2019; 8:cells8070649. [PMID: 31261688 PMCID: PMC6678639 DOI: 10.3390/cells8070649] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/21/2019] [Accepted: 06/25/2019] [Indexed: 12/17/2022] Open
Abstract
The many functions of phosphoinositides in cytosolic signaling were extensively studied; however, their activities in the cell nucleus are much less clear. In this review, we summarize data about their nuclear localization and metabolism, and review the available literature on their involvements in chromatin remodeling, gene transcription, and RNA processing. We discuss the molecular mechanisms via which nuclear phosphoinositides, in particular phosphatidylinositol (4,5)-bisphosphate (PI(4,5)P2), modulate nuclear processes. We focus on PI(4,5)P2’s role in the modulation of RNA polymerase I activity, and functions of the nuclear lipid islets—recently described nucleoplasmic PI(4,5)P2-rich compartment involved in RNA polymerase II transcription. In conclusion, the high impact of the phosphoinositide–protein complexes on nuclear organization and genome functions is only now emerging and deserves further thorough studies.
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36
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Jiang N, Rasmussen JP, Clanton JA, Rosenberg MF, Luedke KP, Cronan MR, Parker ED, Kim HJ, Vaughan JC, Sagasti A, Parrish JZ. A conserved morphogenetic mechanism for epidermal ensheathment of nociceptive sensory neurites. eLife 2019; 8:42455. [PMID: 30855229 PMCID: PMC6450671 DOI: 10.7554/elife.42455] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 03/08/2019] [Indexed: 12/13/2022] Open
Abstract
Interactions between epithelial cells and neurons influence a range of sensory modalities including taste, touch, and smell. Vertebrate and invertebrate epidermal cells ensheath peripheral arbors of somatosensory neurons, including nociceptors, yet the developmental origins and functional roles of this ensheathment are largely unknown. Here, we describe an evolutionarily conserved morphogenetic mechanism for epidermal ensheathment of somatosensory neurites. We found that somatosensory neurons in Drosophila and zebrafish induce formation of epidermal sheaths, which wrap neurites of different types of neurons to different extents. Neurites induce formation of plasma membrane phosphatidylinositol 4,5-bisphosphate microdomains at nascent sheaths, followed by a filamentous actin network, and recruitment of junctional proteins that likely form autotypic junctions to seal sheaths. Finally, blocking epidermal sheath formation destabilized dendrite branches and reduced nociceptive sensitivity in Drosophila. Epidermal somatosensory neurite ensheathment is thus a deeply conserved cellular process that contributes to the morphogenesis and function of nociceptive sensory neurons. Humans and other animals perceive and interact with the outside world through their sensory nervous system. Nerve cells, acting as the body’s ‘telegraph wires’, convey signals from sensory organs – like the eyes – to the brain, which then processes this information and tells the body how to respond. There are different kinds of sensory nerve cells that carry different types of information, but they all associate closely with the tissues and organs they connect to the brain. Human skin contains sensory nerve cells, which underpin our senses of touch and pain. There is a highly specialized, complex connection between some of these nerve cells and cells in the skin: the skin cells wrap tightly around the nerve cells’ free ends, forming sheath-like structures. This ‘ensheathment’ process happens in a wide range of animals, including those with a backbone, like fish and humans, and those without, like insects. Ensheathment is thought to be important for the skin’s nerve cells to work properly. Yet it remains unclear how or when these connections first appear. Jiang et al. therefore wanted to determine the developmental origins of ensheathment and to find out if these were also similar in animals with and without backbones. Experiments using fruit fly and zebrafish embryos revealed that nerve cells, not skin cells, were responsible for forming and maintaining the sheaths. In embryos where groups of sensory nerve cells were selectively killed – either using a laser or by making the cells produce a toxin – ensheathment did not occur. Further studies, using a variety of microscopy techniques, revealed that the molecular machinery required to stabilize the sheaths was similar in both fish and flies, and therefore likely to be conserved across different groups of animals. Removing sheaths in fly embryos led to nerve cells becoming unstable; the animals were also less sensitive to touch. This confirmed that ensheathment was indeed necessary for sensory nerve cells to work properly. By revealing how ensheathment first emerges, these findings shed new light on how the sensory nervous system develops and how its activity is controlled. In humans, skin cells ensheath the nerve cells responsible for sensing pain. A better understanding of how ensheathments first arise could therefore lead to new avenues for treating chronic pain and related conditions.
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Affiliation(s)
- Nan Jiang
- Department of Biology, University of Washington, Seattle, United States
| | - Jeffrey P Rasmussen
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Joshua A Clanton
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Marci F Rosenberg
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Kory P Luedke
- Department of Biology, University of Washington, Seattle, United States
| | - Mark R Cronan
- Department of Molecular Genetics and Microbiology, Duke University, Durham, United States
| | - Edward D Parker
- Department of Opthalmology, University of Washington, Seattle, United States
| | - Hyeon-Jin Kim
- Department of Chemistry, University of Washington, Seattle, United States.,Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - Joshua C Vaughan
- Department of Chemistry, University of Washington, Seattle, United States.,Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - Alvaro Sagasti
- Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Jay Z Parrish
- Department of Biology, University of Washington, Seattle, United States
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The interaction of talin with the cell membrane is essential for integrin activation and focal adhesion formation. Proc Natl Acad Sci U S A 2018; 115:10339-10344. [PMID: 30254158 DOI: 10.1073/pnas.1806275115] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Multicellular organisms have well-defined, tightly regulated mechanisms for cell adhesion. Heterodimeric αβ integrin receptors play central roles in this function and regulate processes for normal cell functions, including signaling, cell migration, and development, binding to the extracellular matrix, and senescence. They are involved in hemostasis and the immune response, participate in leukocyte function, and have biological implications in angiogenesis and cancer. Proper control of integrin activation for cellular communication with the external environment requires several physiological processes. Perturbation of these equilibria may lead to constitutive integrin activation that results in bleeding disorders. Furthermore, integrins play key roles in cancer progression and metastasis in which certain tumor types exhibit higher levels of various integrins. Thus, the integrin-associated signaling complex is important for cancer therapy development. During inside-out signaling, the cytoskeletal protein talin plays a key role in regulating integrin affinity whereby the talin head domain activates integrin by binding to the cytoplasmic tail of β-integrin and acidic membrane phospholipids. To understand the mechanism of integrin activation by talin, we determined the crystal structure of the talin head domain bound to the acidic phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2), allowing us to design a lipid-binding-deficient talin mutant. Our confocal microscopy with talin knockout cells suggests that the talin-cell membrane interaction seems essential for focal adhesion formation and stabilization. Basal integrin activation in Chinese hamster ovary cells suggests that the lipid-binding-deficient talin mutant inhibits integrin activation. Thus, membrane attachment of talin seems necessary for integrin activation and focal adhesion formation.
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38
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Delgado-Ramírez M, López-Izquierdo A, Rodríguez-Menchaca AA. Dual regulation of hEAG1 channels by phosphatidylinositol 4,5-bisphosphate. Biochem Biophys Res Commun 2018; 503:2531-2535. [DOI: 10.1016/j.bbrc.2018.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/03/2018] [Indexed: 12/13/2022]
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Coumans JVF, Davey RJ, Moens PDJ. Cofilin and profilin: partners in cancer aggressiveness. Biophys Rev 2018; 10:1323-1335. [PMID: 30027463 DOI: 10.1007/s12551-018-0445-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/08/2018] [Indexed: 02/07/2023] Open
Abstract
This review covers aspects of cofilin and profilin regulations and their influence on actin polymerisation responsible for cell motility and metastasis. The regulation of their activity by phosphorylation and nitration, miRs, PI(4,5)P2 binding, pH, oxidative stress and post-translational modification is described. In this review, we have highlighted selected similarities, complementarities and differences between the two proteins and how their interplay affects actin filament dynamics.
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Affiliation(s)
- Joelle V F Coumans
- School of Rural Medicine, University of New England, Armidale, Australia
| | - Rhonda J Davey
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, Australia
| | - Pierre D J Moens
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, Australia.
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40
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Tran MH, Seo E, Min S, Nguyen QAT, Choi J, Lee UJ, Hong SS, Kang H, Mansukhani A, Jou I, Lee SY. NEDD4-induced degradative ubiquitination of phosphatidylinositol 4-phosphate 5-kinase α and its implication in breast cancer cell proliferation. J Cell Mol Med 2018; 22:4117-4129. [PMID: 29851245 PMCID: PMC6111810 DOI: 10.1111/jcmm.13689] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/21/2018] [Indexed: 12/15/2022] Open
Abstract
Phosphatidylinositol 4‐phosphate 5‐kinase (PIP5K) family members generate phosphatidylinositol 4,5‐bisphosphate (PIP2), a critical lipid regulator of diverse physiological processes. The PIP5K‐dependent PIP2 generation can also act upstream of the oncogenic phosphatidylinositol 3‐kinase (PI3K)/Akt pathway. Many studies have demonstrated various mechanisms of spatiotemporal regulation of PIP5K catalytic activity. However, there are few studies on regulation of PIP5K protein stability. Here, we examined potential regulation of PIP5Kα, a PIP5K isoform, via ubiquitin‐proteasome system, and its implication for breast cancer. Our results showed that the ubiquitin ligase NEDD4 (neural precursor cell expressed, developmentally down‐regulated gene 4) mediated ubiquitination and proteasomal degradation of PIP5Kα, consequently reducing plasma membrane PIP2 level. NEDD4 interacted with the C‐terminal region and ubiquitinated the N‐terminal lysine 88 in PIP5Kα. In addition, PIP5Kα gene disruption inhibited epidermal growth factor (EGF)‐induced Akt activation and caused significant proliferation defect in breast cancer cells. Notably, PIP5Kα K88R mutant that was resistant to NEDD4‐mediated ubiquitination and degradation showed more potentiating effects on Akt activation by EGF and cell proliferation than wild‐type PIP5Kα. Collectively, these results suggest that PIP5Kα is a novel degradative substrate of NEDD4 and that the PIP5Kα‐dependent PIP2 pool contributing to breast cancer cell proliferation through PI3K/Akt activation is negatively controlled by NEDD4.
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Affiliation(s)
- Mai Hoang Tran
- Department of Biomedical Sciences, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Eunjeong Seo
- Department of Biomedical Sciences, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Soohong Min
- School of Biological Sciences, Institute of Molecular Biology and Genetics, Seoul National University, Seoul, Korea
| | - Quynh-Anh T Nguyen
- Department of Biomedical Sciences, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Juyong Choi
- Department of Biomedical Sciences, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Uk-Jin Lee
- Department of Biomedical Sciences, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Soon-Sun Hong
- Department of Biomedical Sciences, Inha University College of Medicine, Incheon, Korea
| | - Hyuk Kang
- Department of Chemistry, Ajou University, Suwon, Korea
| | - Alka Mansukhani
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
| | - Ilo Jou
- Department of Biomedical Sciences, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
| | - Sang Yoon Lee
- Department of Biomedical Sciences, Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Korea
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41
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Rodríguez-Escudero I, Fernández-Acero T, Cid VJ, Molina M. Heterologous mammalian Akt disrupts plasma membrane homeostasis by taking over TORC2 signaling in Saccharomyces cerevisiae. Sci Rep 2018; 8:7732. [PMID: 29769614 PMCID: PMC5955888 DOI: 10.1038/s41598-018-25717-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/26/2018] [Indexed: 01/21/2023] Open
Abstract
The Akt protein kinase is the main transducer of phosphatidylinositol-3,4,5-trisphosphate (PtdIns3,4,5P3) signaling in higher eukaryotes, controlling cell growth, motility, proliferation and survival. By co-expression of mammalian class I phosphatidylinositol 3-kinase (PI3K) and Akt in the Saccharomyces cerevisiae heterologous model, we previously described an inhibitory effect on yeast growth that relied on Akt kinase activity. Here we report that PI3K-Akt expression in yeast triggers the formation of large plasma membrane (PM) invaginations that were marked by actin patches, enriched in PtdIns4,5P2 and associated to abnormal intracellular cell wall deposits. These effects of Akt were mimicked by overproduction of the PtdIns4,5P2 effector Slm1, an adaptor of the Ypk1 and Ypk2 kinases in the TORC2 pathway. Although Slm1 was phosphorylated in vivo by Akt, TORC2-dependent Ypk1 activation did not occur. However, PI3K-activated Akt suppressed the lethality derived from inactivation of either TORC2 or Ypk protein kinases. Thus, heterologous co-expression of PI3K and Akt in yeast short-circuits PtdIns4,5P2- and TORC2-signaling at the level of the Slm-Ypk complex, overriding some of its functions. Our results underscore the importance of phosphoinositide-dependent kinases as key actors in the homeostasis and dynamics of the PM.
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Affiliation(s)
- Isabel Rodríguez-Escudero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Madrid, Spain
| | - Teresa Fernández-Acero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Madrid, Spain
| | - Víctor J Cid
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Madrid, Spain.
| | - María Molina
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Madrid, Spain
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42
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Zhang J, Chen X, Xue Y, Gamper N, Zhang X. Beyond voltage-gated ion channels: Voltage-operated membrane proteins and cellular processes. J Cell Physiol 2018; 233:6377-6385. [PMID: 29667735 DOI: 10.1002/jcp.26555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 02/20/2018] [Indexed: 12/26/2022]
Abstract
Voltage-gated ion channels were believed to be the only voltage-sensitive proteins in excitable (and some non-excitable) cells for a long time. Emerging evidence indicates that the voltage-operated model is shared by some other transmembrane proteins expressed in both excitable and non-excitable cells. In this review, we summarize current knowledge about voltage-operated proteins, which are not classic voltage-gated ion channels as well as the voltage-dependent processes in cells for which single voltage-sensitive proteins have yet to be identified. Particularly, we will focus on the following. (1) Voltage-sensitive phosphoinositide phosphatases (VSP) with four transmembrane segments homologous to the voltage sensor domain (VSD) of voltage-gated ion channels; VSPs are the first family of proteins, other than the voltage-gated ion channels, for which there is sufficient evidence for the existence of the VSD domain; (2) Voltage-gated proton channels comprising of a single voltage-sensing domain and lacking an identified pore domain; (3) G protein coupled receptors (GPCRs) that mediate the depolarization-evoked potentiation of Ca2+ mobilization; (4) Plasma membrane (PM) depolarization-induced but Ca2+ -independent exocytosis in neurons. (5) Voltage-dependent metabolism of phosphatidylinositol 4,5-bisphosphate (PtdIns[4,5]P2 , PIP2 ) in the PM. These recent discoveries expand our understanding of voltage-operated processes within cellular membranes.
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Affiliation(s)
- Jianping Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Xingjuan Chen
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana.,Beijing Key Laboratory of Diabetes Prevention and Research, Lu He Hospital, Capital Medical University, Beijing, China
| | - Yucong Xue
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Nikita Gamper
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Xuan Zhang
- Department of Pharmacology, Hebei University of Chinese Medicine, Shijiazhuang, China
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Nguyen TTN, Seo E, Choi J, Le OTT, Kim JY, Jou I, Lee SY. Phosphatidylinositol 4-phosphate 5-kinase α contributes to Toll-like receptor 2-mediated immune responses in microglial cells stimulated with lipoteichoic acid. Cell Signal 2017; 38:159-170. [DOI: 10.1016/j.cellsig.2017.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/21/2017] [Accepted: 07/12/2017] [Indexed: 12/11/2022]
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Chen C, Wang X, Fang J, Xue J, Xiong X, Huang Y, Hu J, Ling K. EGFR-induced phosphorylation of type Iγ phosphatidylinositol phosphate kinase promotes pancreatic cancer progression. Oncotarget 2017; 8:42621-42637. [PMID: 28388589 PMCID: PMC5522093 DOI: 10.18632/oncotarget.16730] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 01/24/2017] [Indexed: 01/05/2023] Open
Abstract
Pancreatic cancer is one of the deadliest malignancies and effective treatment has always been lacking. In current study, we investigated how the type Iγ phosphatidylinositol phosphate kinase (PIPKIγ) participates in the progression of pancreatic ductal adenocarcinoma (PDAC) for novel therapeutic potentials against this lethal disease. We found that PIPKIγ is up-regulated in all tested PDAC cell lines. The growth factor (including EGFR)-induced tyrosine phosphorylation of PIPKIγ is significantly elevated in in situ and metastatic PDAC tissues. Loss of PIPKIγ inhibits the aggressiveness of PDAC cells by restraining the activities of AKT and STAT3, as well as MT1-MMP expression. Therefore when planted into the pancreas of nude mice, PIPKIγ-depleted PDAC cells exhibits substantially repressed tumor growth and metastasis comparing to control PDAC cells. Results from further studies showed that the phosphorylation-deficient PIPKIγ mutant, unlike its wild-type counterpart, cannot rescue PDAC progression inhibited by PIPKIγ depletion. These findings indicate that PIPKIγ, functioning downstream of EGFR signaling, is critical to the progression of PDAC, and suggest that PIPKIγ is potentially a valuable therapeutic target for PDAC treatment.
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Affiliation(s)
- Chunhua Chen
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
- These authors have contributed equally to this work
| | - Xiangling Wang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
- These authors have contributed equally to this work
| | - Juemin Fang
- Shanghai Tenth People’s Hospital, Tongji University, Shanghai, China
- These authors have contributed equally to this work
| | - Junli Xue
- Shanghai East Hospital, Tongji University, Shanghai, China
| | - Xunhao Xiong
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Yan Huang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Jinghua Hu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Kun Ling
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
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45
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Thapa N, Tan X, Choi S, Wise T, Anderson RA. PIPKIγ and talin couple phosphoinositide and adhesion signaling to control the epithelial to mesenchymal transition. Oncogene 2017; 36:899-911. [PMID: 27452517 PMCID: PMC6344042 DOI: 10.1038/onc.2016.267] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 06/03/2016] [Accepted: 06/17/2016] [Indexed: 12/15/2022]
Abstract
Epithelial cells acquire migratory/invasive and stemness traits upon conversion to the mesenchymal phenotype. The expression of E-cadherin is a key to this transition; yet precise understanding of the pathways involved in integrating E-cadherin loss to the gain of mesenchymal traits remains poorly understood. Here, we show that phosphoinositide-generating enzyme, PIPKIγ, expression is upregulated upon epithelial-mesenchymal transition (EMT) and together with the cytoskeletal protein talin assemble into a signaling complex upon E-cadherin loss. PIPKIγ and talin together control the adhesion and phosphoinositide signaling that regulates conversion to the mesenchymal phenotypes. PIPKIγ and talin regulate the stability of E-cadherin transcriptional repressors, snail and slug, induced by transforming growth factor-β1 or extracellular matrix protein. Loss of PIPKIγ or talin or their interaction impaired EMT and the acquisition of cell motility and stemness. This demonstrates a mechanism where a phosphoinositide-generating enzyme PIPKIγ couples with a cytoskeletal protein talin to control the acquisition of mesenchymal phenotypes.
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Affiliation(s)
- N Thapa
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - X Tan
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - S Choi
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - T Wise
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
| | - R A Anderson
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
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Agonist-stimulated phosphatidylinositol-3,4,5-trisphosphate generation by scaffolded phosphoinositide kinases. Nat Cell Biol 2016; 18:1324-1335. [PMID: 27870828 DOI: 10.1038/ncb3441] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 10/20/2016] [Indexed: 12/11/2022]
Abstract
Generation of the lipid messenger phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) is crucial for development, cell growth and survival, and motility, and it becomes dysfunctional in many diseases including cancers. Here we reveal a mechanism for PtdIns(3,4,5)P3 generation by scaffolded phosphoinositide kinases. In this pathway, class I phosphatidylinositol-3-OH kinase (PI(3)K) is assembled by IQGAP1 with PI(4)KIIIα and PIPKIα, which sequentially generate PtdIns(3,4,5)P3 from phosphatidylinositol. By scaffolding these kinases into functional proximity, the PtdIns(4,5)P2 generated is selectively used by PI(3)K for PtdIns(3,4,5)P3 generation, which then signals to PDK1 and Akt that are also in the complex. Moreover, multiple receptor types stimulate the assembly of this IQGAP1-PI(3)K signalling complex. Blockade of IQGAP1 interaction with PIPKIα or PI(3)K inhibited PtdIns(3,4,5)P3 generation and signalling, and selectively diminished cancer cell survival, revealing a target for cancer chemotherapy.
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Abstract
Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a lipid second messenger that regulates a wide array of essential cellular events, such as signal transduction, vesicle trafficking, actin cytoskeleton dynamics, adhesion, and motility. To control the spatiotemporal production of PI(4,5)P2, the activity of type 1 phosphotidylinositol-4-phosphate-5-kinases (PIPKIs) is tightly regulated by small GTPases and another signaling lipid, phosphatidic acid (PA). It is of interest that PI(4,5)P2 is also a critical cofactor for the activation of the PA-generating enzyme, phospholipase D (PLD). It has been proposed that the reciprocal stimulation of PLD and PIPKI enzymes enables a rapid feedforward stimulation loop for the localized and acute generation of signaling lipids that are critical for the regulation of actin cytoskeletal reorganization and membrane trafficking. Here, we outline the methods for the expression and purification of PIPKIγ from bacteria, determination of direct PA binding, and activation of PIPKIγ using in vitro liposomes assays, and examination of actin cytoskeletal reorganization promoted by the PA-PIPKIγ signaling in intact cells using fluorescent microscopy.
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Ikonomov OC, Sbrissa D, Delvecchio K, Rillema JA, Shisheva A. Unexpected severe consequences of Pikfyve deletion by aP2- or Aq-promoter-driven Cre expression for glucose homeostasis and mammary gland development. Physiol Rep 2016; 4:4/11/e12812. [PMID: 27273882 PMCID: PMC4908490 DOI: 10.14814/phy2.12812] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Accepted: 05/04/2016] [Indexed: 01/03/2023] Open
Abstract
Systemic deficiency of PIKfyve, the evolutionarily conserved phosphoinositide kinase synthesizing cellular PtdIns5P and PtdIns(3,5)P2 and implicated in insulin signaling, causes early embryonic death in mice. In contrast, mice with muscle‐specific Pikfyve disruption have normal lifespan but exhibit early‐age whole‐body glucose intolerance and muscle insulin resistance, thus establishing the key role of muscle PIKfyve in glucose homeostasis. Fat and muscle tissues control postprandial glucose clearance through different mechanisms, raising questions as to whether adipose Pikfyve disruption will also trigger whole‐body metabolic abnormalities, and if so, what the mechanism might be. To clarify these issues, here we have characterized two new mouse models with adipose tissue disruption of Pikfyve through Cre recombinase expression driven by adipose‐specific aP2‐ or adiponectin (Aq) promoters. Whereas both mouse lines were ostensibly normal until adulthood, their glucose homeostasis and systemic insulin sensitivity were severely dysregulated. These abnormalities stemmed in part from accelerated fat‐cell lipolysis and elevated serum FFA. Intriguingly, aP2‐Cre‐PIKfyvefl/fl but not Aq‐Cre‐PIKfyvefl/fl females had severely impaired pregnancy‐induced mammary gland differentiation and lactogenesis, consistent with aP2‐Cre‐mediated Pikfyve excision in nonadipogenic tissues underlying this defect. Intriguingly, whereas mammary glands from postpartum control and Aq‐Cre‐PIKfyvefl/fl mice or ex vivo mammary gland explants showed profound upregulation of PIKfyve protein levels subsequent to prolactin receptor activation, such increases were not apparent in aP2‐Cre‐PIKfyvefl/fl females. Collectively, our data identify for the first time that adipose tissue Pikfyve plays a key role in the mechanisms regulating glucose homeostasis and that the PIKfyve pathway is critical in mammary epithelial differentiation during pregnancy and lactogenesis downstream of prolactin receptor signaling.
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Affiliation(s)
- Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Diego Sbrissa
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Khortnal Delvecchio
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - James A Rillema
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
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Sun M, Cai J, Anderson RA, Sun Y. Type I γ Phosphatidylinositol Phosphate 5-Kinase i5 Controls the Ubiquitination and Degradation of the Tumor Suppressor Mitogen-inducible Gene 6. J Biol Chem 2016; 291:21461-21473. [PMID: 27557663 DOI: 10.1074/jbc.m116.736041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 08/11/2016] [Indexed: 12/15/2022] Open
Abstract
Mitogen-inducible gene 6 (Mig6) is a tumor suppressor, and the disruption of Mig6 expression is associated with cancer development. Mig6 directly interacts with epidermal growth factor receptor (EGFR) to suppress the activation and downstream signaling of EGFR. Therefore, loss of Mig6 enhances EGFR-mediated signaling and promotes EGFR-dependent carcinogenesis. The molecular mechanism modulating Mig6 expression in cancer remains unclear. Here we demonstrate that type I γ phosphatidylinositol phosphate 5-kinase i5 (PIPKIγi5), an enzyme producing phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), stabilizes Mig6 expression. Knockdown of PIPKIγi5 leads to the loss of Mig6 expression, which dramatically enhances and prolongs EGFR-mediated cell signaling. Loss of PIPKIγi5 significantly promotes Mig6 protein degradation via proteasomes, but it does not affect the Mig6 mRNA level. PIPKIγi5 directly interacts with the E3 ubiquitin ligase neuronal precursor cell-expressed developmentally down-regulated 4-1 (NEDD4-1). The C-terminal domain of PIPKIγi5 and the WW1 and WW2 domains of NEDD4-1 are required for their interaction. The C2 domain of NEDD4-1 is required for its interaction with PtdIns(4,5)P2 By binding with NEDD4-1 and producing PtdIns(4,5)P2, PIPKIγi5 perturbs NEDD4-1-mediated Mig6 ubiquitination and the subsequent proteasomal degradation. Thus, loss of NEDD4-1 can rescue Mig6 expression in PIPKIγi5 knockdown cells. In this way, PIPKIγi5, NEDD4-1, and Mig6 form a novel molecular nexus that controls EGFR activation and downstream signaling.
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Affiliation(s)
- Ming Sun
- From the Philips Institute for Oral Health Research, School of Dentistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298 and
| | - Jinyang Cai
- From the Philips Institute for Oral Health Research, School of Dentistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298 and
| | - Richard A Anderson
- the Molecular and Cellular Pharmacology Program, University of Wisconsin, School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Yue Sun
- From the Philips Institute for Oral Health Research, School of Dentistry and Massey Cancer Center, Virginia Commonwealth University, Richmond, Virginia 23298 and
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50
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Gulshan K, Brubaker G, Conger H, Wang S, Zhang R, Hazen SL, Smith JD. PI(4,5)P2 Is Translocated by ABCA1 to the Cell Surface Where It Mediates Apolipoprotein A1 Binding and Nascent HDL Assembly. Circ Res 2016; 119:827-38. [PMID: 27514935 DOI: 10.1161/circresaha.116.308856] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 08/11/2016] [Indexed: 12/23/2022]
Abstract
RATIONALE The molecular mechanism by which ATP-binding cassette transporter A1 (ABCA1) mediates cellular binding of apolipoprotein A-I (apoA1) and nascent high-density lipoprotein (HDL) assembly is not well understood. OBJECTIVE To determine the cell surface lipid that mediates apoA1 binding to ABCA1-expressing cells and the role it plays in nascent HDL assembly. METHODS AND RESULTS Using multiple biochemical and biophysical methods, we found that apoA1 binds specifically to phosphatidylinositol (4,5) bis-phosphate (PIP2). Flow cytometry and PIP2 reporter-binding assays demonstrated that ABCA1 led to PIP2 redistribution from the inner to the outer leaflet of the plasma membrane. Enzymatic cleavage of cell surface PIP2 or decreased cellular PIP2 by knockdown of phosphatidylinositol-5-phosphate 4-kinase impaired apoA1 binding and cholesterol efflux to apoA1. PIP2 also increased the spontaneous solubilization of phospholipid liposomes by apoA1. Using site-directed mutagenesis, we found that ABCA1's PIP2 and phosphatidylserine translocase activities are independent from each other. Furthermore, we discovered that PIP2 is effluxed from cells to apoA1, where it is associated with HDL in plasma, and that PIP2 on HDL is taken up by target cells in a scavenger receptor-BI-dependent manner. Mouse plasma PIP2 levels are apoA1 gene dosage-dependent and are >1 μM in apoA1 transgenic mice. CONCLUSIONS ABCA1 has PIP2 floppase activity, which increases cell surface PIP2 levels that mediate apoA1 binding and lipid efflux during nascent HDL assembly. We found that PIP2 itself is effluxed to apoA1 and it circulates on plasma HDL, where it can be taken up via the HDL receptor scavenger receptor-BI.
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Affiliation(s)
- Kailash Gulshan
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH.
| | - Gregory Brubaker
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Heather Conger
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Shuhui Wang
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Renliang Zhang
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Stanley L Hazen
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH
| | - Jonathan D Smith
- From the Department of Cellular and Molecular Medicine (K.G., G.B., H.C., S.W., R.Z., S.L.H., J.D.S.) and Department of Cardiovascular Medicine (S.L.H., J.D.S.), Cleveland Clinic, OH.
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