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Guo Z, Jiang CH, Tong C, Yang Y, Wang Z, Lam SM, Wang D, Li R, Shui G, Shi YS, Liu JJ. Activity-dependent PI4P synthesis by PI4KIIIα regulates long-term synaptic potentiation. Cell Rep 2022; 38:110452. [PMID: 35235793 DOI: 10.1016/j.celrep.2022.110452] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 12/30/2021] [Accepted: 02/07/2022] [Indexed: 01/11/2023] Open
Abstract
Phosphatidylinositol 4-phosphate (PI4P) is a low abundant phospholipid with important roles in lipid transport and membrane trafficking. However, little is known of its metabolism and function in neurons. Here, we investigate its subcellular distribution and functional roles in dendrites of rodent hippocampal neurons during resting state and long-term synaptic potentiation (LTP). We show that neural activity causes dynamic reversible changes in PI4P metabolism in dendrites. Upon LTP induction, PI4KIIIα, a type III phosphatidylinositol 4-kinase, localizes to the dendritic plasma membrane (PM) in a calcium-dependent manner and causes substantial increase in the levels of PI4P. Acute inhibition of PI4KIIIα activity abolishes trafficking of the AMPA-type glutamate receptor to the PM during LTP induction, and silencing of PI4KIIIα expression in the hippocampal CA1 region causes severe impairment of LTP and long-term memory. Collectively, our results identify an essential role for PI4KIIIα-dependent PI4P synthesis in synaptic plasticity of central nervous system neurons.
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Affiliation(s)
- Zhenzhen Guo
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Chao-Hua Jiang
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of Nanjing University, Nanjing 210061, China
| | - Chunfang Tong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yanrui Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Zehua Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Dou Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Rui Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China
| | - Yun Stone Shi
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center of Nanjing University, Nanjing 210061, China
| | - Jia-Jia Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100039, China.
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52
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Batrouni AG, Bag N, Phan HT, Baird BA, Baskin JM. A palmitoylation code controls PI4KIIIα complex formation and PI(4,5)P2 homeostasis at the plasma membrane. J Cell Sci 2022; 135:272297. [PMID: 34569608 DOI: 10.1242/jcs.259365] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/12/2022] Open
Abstract
Phosphatidylinositol 4-kinase IIIα (PI4KIIIα) is the major enzyme responsible for generating phosphatidylinositol (4)-phosphate [PI(4)P] at the plasma membrane. This lipid kinase forms two multicomponent complexes, both including a palmitoylated anchor, EFR3. Whereas both PI4KIIIα complexes support production of PI(4)P, the distinct functions of each complex and mechanisms underlying the interplay between them remain unknown. Here, we present roles for differential palmitoylation patterns within a tri-cysteine motif in EFR3B (Cys5, Cys7 and Cys8) in controlling the distribution of PI4KIIIα between these two complexes at the plasma membrane and corresponding functions in phosphoinositide homeostasis. Spacing of palmitoyl groups within three doubly palmitoylated EFR3B 'lipoforms' affects both interactions between EFR3B and TMEM150A, a transmembrane protein governing formation of a PI4KIIIα complex functioning in rapid phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2] resynthesis following phospholipase C signaling, and EFR3B partitioning within liquid-ordered and -disordered regions of the plasma membrane. This work identifies a palmitoylation code involved in controlling protein-protein and protein-lipid interactions that affect a plasma membrane-resident lipid biosynthetic pathway.
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Affiliation(s)
- Alex G Batrouni
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA.,Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA
| | - Nirmalya Bag
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Henry T Phan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Barbara A Baird
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jeremy M Baskin
- Weill Institute for Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
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53
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Maltan L, Andova AM, Derler I. The Role of Lipids in CRAC Channel Function. Biomolecules 2022; 12:biom12030352. [PMID: 35327543 PMCID: PMC8944985 DOI: 10.3390/biom12030352] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/12/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022] Open
Abstract
The composition and dynamics of the lipid membrane define the physical properties of the bilayer and consequently affect the function of the incorporated membrane transporters, which also applies for the prominent Ca2+ release-activated Ca2+ ion channel (CRAC). This channel is activated by receptor-induced Ca2+ store depletion of the endoplasmic reticulum (ER) and consists of two transmembrane proteins, STIM1 and Orai1. STIM1 is anchored in the ER membrane and senses changes in the ER luminal Ca2+ concentration. Orai1 is the Ca2+-selective, pore-forming CRAC channel component located in the plasma membrane (PM). Ca2+ store-depletion of the ER triggers activation of STIM1 proteins, which subsequently leads to a conformational change and oligomerization of STIM1 and its coupling to as well as activation of Orai1 channels at the ER-PM contact sites. Although STIM1 and Orai1 are sufficient for CRAC channel activation, their efficient activation and deactivation is fine-tuned by a variety of lipids and lipid- and/or ER-PM junction-dependent accessory proteins. The underlying mechanisms for lipid-mediated CRAC channel modulation as well as the still open questions, are presented in this review.
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54
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de la Cruz L, Riquelme R, Vivas O, Barria A, Jensen JB. Dishevelled coordinates phosphoinositide kinases PI4KIIIα and PIP5KIγ for efficient PtdInsP2 synthesis. J Cell Sci 2022; 135:274231. [PMID: 34982154 PMCID: PMC8919331 DOI: 10.1242/jcs.259145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 12/14/2021] [Indexed: 02/05/2023] Open
Abstract
Phosphatidylinositol(4,5)-bisphosphate (PtdInsP2) is an important modulator of many cellular processes, and its abundance in the plasma membrane is closely regulated. We examined the hypothesis that members of the Dishevelled scaffolding protein family can bind the lipid kinases phosphatidylinositol 4-kinase (PI4K) and phosphatidylinositol 4-phosphate 5-kinase (PIP5K), facilitating synthesis of PtdInsP2 directly from phosphatidylinositol. We used several assays for PtdInsP2 to examine the cooperative function of phosphoinositide kinases and the Dishevelled protein Dvl3 in the context of two receptor signaling cascades. Simultaneous overexpression of PI4KIIIα (also known as PI4KA) and PIP5KIγ (also known as PIP5K1C) had a synergistic effect on PtdInsP2 synthesis that was recapitulated by overexpression of Dvl3. Increasing the activity of Dvl3 by overexpression increased resting plasma membrane PtdInsP2. Knockdown of Dvl3 reduced resting plasma membrane PtdInsP2 and slowed PtdInsP2 resynthesis following receptor activation. We confirm that Dvl3 promotes coupling of PI4KIIIα and PIP5KIγ and show that this interaction is essential for efficient resynthesis of PtdInsP2 following receptor activation.
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55
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Zhang Q, Zhang B, Lim NKH, Zhang X, Meng S, Nyengaard JR, Huang F, Wang WA. Hyccin/FAM126A deficiency reduces glial enrichment and axonal sheath, which are rescued by overexpression of a plasma membrane-targeting PI4KIIIα in Drosophila. Biochem Biophys Res Commun 2022; 589:71-77. [PMID: 34894559 DOI: 10.1016/j.bbrc.2021.11.106] [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: 09/03/2021] [Revised: 10/06/2021] [Accepted: 11/30/2021] [Indexed: 02/07/2023]
Abstract
Hyccin/FAM126A mutations are linked to hypomyelination and congenital cataract disease (HCC), but whether and how Hyccin/FAM126A deficiency causes hypomyelination remains undetermined. This study shows Hyccin/FAM126A expression was necessary for the expression of other components of the PI4KIIIα complex in Drosophila. Knockdown of Hyccin/FAM126A in glia reduced the enrichment of glial cells, disrupted axonal sheaths and visual ability in the visual system, and these defects could be fully rescued by overexpressing either human FAM126A or FAM126B, and partially rescued by overexpressing a plasma membrane-targeting recombinant mouse PI4KIIIα. Additionally, PI4KIIIα knockdown in glia phenocopied Hyccin/FAM126A knockdown, and this was partially rescued by overexpressing the recombinant PI4KIIIα, but not human FAM126A or FAM126B. This study establishes an animal model of HCC and indicates that Hyccin/FAM126A plays an essential role in glial enrichment and axonal sheath in a cell-autonomous manner in the visual system via controlling the expression and stabilization of the PI4KIIIα complex at the plasma membrane.
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Affiliation(s)
- Qichao Zhang
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100190, China; Sino-Danish Center for Education and Research, Beijing, 100190, China; Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 201210, China; Department of Clinical Medicine, Core Center for Molecular Morphology, Section for Stereology and Microscopy, Aarhus University, Aarhus, 8200, Denmark
| | - Baozhu Zhang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Nastasia K H Lim
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 201210, China; Nuo-beta Pharmaceutical Technology (Shanghai) Co. Ltd., Shanghai, 201210, China; Shanghai Institute of Materia Medica, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Xiao Zhang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Shiquan Meng
- Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 201210, China; Laboratory of Molecular Neurobiology, School of Life Sciences, Shanghai University, Shanghai, 200072, China
| | - Jens R Nyengaard
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100190, China; Sino-Danish Center for Education and Research, Beijing, 100190, China; Department of Clinical Medicine, Core Center for Molecular Morphology, Section for Stereology and Microscopy, Aarhus University, Aarhus, 8200, Denmark
| | - Fude Huang
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100190, China; Sino-Danish Center for Education and Research, Beijing, 100190, China; Shanghai Advanced Research Institute, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 201210, China; Nuo-beta Pharmaceutical Technology (Shanghai) Co. Ltd., Shanghai, 201210, China.
| | - Wen-An Wang
- Department of Neurology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, 200092, China; Department of Neurology, Xinhua Hospital Chongming Branch, Shanghai 202150, China.
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56
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Noack LC, Bayle V, Armengot L, Rozier F, Mamode-Cassim A, Stevens FD, Caillaud MC, Munnik T, Mongrand S, Pleskot R, Jaillais Y. A nanodomain-anchored scaffolding complex is required for the function and localization of phosphatidylinositol 4-kinase alpha in plants. THE PLANT CELL 2022; 34:302-332. [PMID: 34010411 PMCID: PMC8774046 DOI: 10.1093/plcell/koab135] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 05/10/2021] [Indexed: 05/24/2023]
Abstract
Phosphoinositides are low-abundant lipids that participate in the acquisition of membrane identity through their spatiotemporal enrichment in specific compartments. Phosphatidylinositol 4-phosphate (PI4P) accumulates at the plant plasma membrane driving its high electrostatic potential, and thereby facilitating interactions with polybasic regions of proteins. PI4Kα1 has been suggested to produce PI4P at the plasma membrane, but how it is recruited to this compartment is unknown. Here, we pin-point the mechanism that tethers Arabidopsis thaliana phosphatidylinositol 4-kinase alpha1 (PI4Kα1) to the plasma membrane via a nanodomain-anchored scaffolding complex. We established that PI4Kα1 is part of a complex composed of proteins from the NO-POLLEN-GERMINATION, EFR3-OF-PLANTS, and HYCCIN-CONTAINING families. Comprehensive knockout and knockdown strategies revealed that subunits of the PI4Kα1 complex are essential for pollen, embryonic, and post-embryonic development. We further found that the PI4Kα1 complex is immobilized in plasma membrane nanodomains. Using synthetic mis-targeting strategies, we demonstrate that a combination of lipid anchoring and scaffolding localizes PI4Kα1 to the plasma membrane, which is essential for its function. Together, this work opens perspectives on the mechanisms and function of plasma membrane nanopatterning by lipid kinases.
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Affiliation(s)
- Lise C Noack
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, F-69342, Lyon, France
| | - Vincent Bayle
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, F-69342, Lyon, France
| | - Laia Armengot
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, F-69342, Lyon, France
| | - Frédérique Rozier
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, F-69342, Lyon, France
| | - Adiilah Mamode-Cassim
- Laboratoire de Biogenèse Membranaire, UMR5200, Université de Bordeaux, CNRS, 33140 Villenave d’Ornon, France
- Agroécologie, AgroSup Dijon, CNRS, INRA, University Bourgogne Franche-Comté, F-21000 Dijon, France
| | - Floris D Stevens
- Research Cluster Green Life Sciences, Section Plant Cell Biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, 1090 GE, The Netherlands
| | - Marie-Cécile Caillaud
- Laboratoire Reproduction et Développement des Plantes, Univ Lyon, ENS de Lyon, Université Claude Bernard Lyon 1, CNRS, INRAE, F-69342, Lyon, France
| | - Teun Munnik
- Research Cluster Green Life Sciences, Section Plant Cell Biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, 1090 GE, The Netherlands
| | - Sébastien Mongrand
- Laboratoire de Biogenèse Membranaire, UMR5200, Université de Bordeaux, CNRS, 33140 Villenave d’Ornon, France
| | - Roman Pleskot
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 16502 Prague 6, Czech Republic
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57
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Abstract
Phosphoinositides are signalling lipids derived from phosphatidylinositol, a ubiquitous phospholipid in the cytoplasmic leaflet of eukaryotic membranes. Initially discovered for their roles in cell signalling, phosphoinositides are now widely recognized as key integrators of membrane dynamics that broadly impact on all aspects of cell physiology and on disease. The past decade has witnessed a vast expansion of our knowledge of phosphoinositide biology. On the endocytic and exocytic routes, phosphoinositides direct the inward and outward flow of membrane as vesicular traffic is coupled to the conversion of phosphoinositides. Moreover, recent findings on the roles of phosphoinositides in autophagy and the endolysosomal system challenge our view of lysosome biology. The non-vesicular exchange of lipids, ions and metabolites at membrane contact sites in between organelles has also been found to depend on phosphoinositides. Here we review our current understanding of how phosphoinositides shape and direct membrane dynamics to impact on cell physiology, and provide an overview of emerging concepts in phosphoinositide regulation.
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Laquel P, Testet E, Tuphile K, Cullin C, Fouillen L, Bessoule JJ, Doignon F. Phosphoinositides containing stearic acid are required for interaction between Rho GTPases and the exocyst to control the late steps of polarised exocytosis. Traffic 2021; 23:120-136. [PMID: 34908215 DOI: 10.1111/tra.12829] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 11/18/2021] [Accepted: 12/07/2021] [Indexed: 11/27/2022]
Abstract
Cell polarity is achieved by regulators such as small G proteins, exocyst members and phosphoinositides, with the latter playing a key role when bound to the exocyst proteins Sec3p and Exo70p, and Rho GTPases. This ensures asymmetric growth via the routing of proteins and lipids to the cell surface using actin cables. Previously, using a yeast mutant for a lysophosphatidylinositol acyl transferase encoded by the PSI1 gene, we demonstrated the role of stearic acid in the acyl chain of phosphoinositides in cytoskeletal organisation and secretion. Here, we use a genetic approach to characterise the effect on late steps of the secretory pathway. The constitutive overexpression of PSI1 in mutants affecting kinases involved in the phosphoinositide pathway demonstrated the role of molecular species containing stearic acid in bypassing a lack of phosphatidylinositol-4-phosphate PI(4)P at the plasma membrane, which is essential for the function of the Cdc42p module. Decreasing the levels of stearic acid-containing phosphoinositides modifies the environment of the actors involved in the control of late steps in the secretory pathway. This leads to decreased interactions between Exo70p and Sec3p, with Cdc42p, Rho1p and Rho3p, due to disruption of the GTP/GDP ratio of at least Rho1p and Rho3p GTPases, thereby preventing activation of the exocyst.
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Affiliation(s)
- P Laquel
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - E Testet
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - K Tuphile
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - C Cullin
- Univ. Bordeaux, CNRS, Laboratoire de Chimie Biologie des Membranes & des Nano-objets, UMR 5248, Pessac, France
| | - L Fouillen
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France.,Metabolome Facility of Bordeaux, Functional Genomics Centre, F-33883 Villenave d'Ornon, France
| | - J J Bessoule
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - F Doignon
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
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59
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Membrane pools of phosphatidylinositol-4-phosphate regulate KCNQ1/KCNE1 membrane expression. Commun Biol 2021; 4:1392. [PMID: 34907346 PMCID: PMC8671492 DOI: 10.1038/s42003-021-02909-1] [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: 07/23/2020] [Accepted: 11/24/2021] [Indexed: 11/23/2022] Open
Abstract
Plasma membrane phosphatidylinositol 4-phosphate (PI4P) is a precursor of PI(4,5)P2, an important regulator of a large number of ion channels. Although the role of the phospholipid PI(4,5)P2 in stabilizing ion channel function is well established, little is known about the role of phospholipids in channel membrane localization and specifically the role of PI4P in channel function and localization. The phosphatidylinositol 4-kinases (PI4Ks) synthesize PI4P. Our data show that inhibition of PI4K and prolonged decrease of levels of plasma membrane PI4P lead to a decrease in the KCNQ1/KCNE1 channel membrane localization and function. In addition, we show that mutations linked to Long QT syndrome that affect channel interactions with phospholipids lead to a decrease in membrane expression. We show that expression of a LQT1-associated C-terminal deletion mutant abolishes PI4Kinase-mediated decrease in membrane expression and rescues membrane expression for phospholipid-targeting mutations. Our results indicate a novel role for PI4P on ion channel regulation. Our data suggest that decreased membrane PI4P availability to the channel, either due to inhibition of PI4K or as consequence of mutations, dramatically inhibits KCNQ1/KCNE1 channel membrane localization and current. Our results may have implications to regulation of other PI4P binding channels.
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60
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Bura A, Jurak Begonja A. Imaging of Intracellular and Plasma Membrane Pools of PI(4,5)P 2 and PI4P in Human Platelets. Life (Basel) 2021; 11:1331. [PMID: 34947862 PMCID: PMC8705196 DOI: 10.3390/life11121331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 11/23/2021] [Accepted: 11/28/2021] [Indexed: 12/25/2022] Open
Abstract
Phosphoinositides (PIs) are phosphorylated membrane lipids that have a plethora of roles in the cell, including vesicle trafficking, signaling, and actin reorganization. The most abundant PIs in the cell are phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] and phosphatidylinositol-4-monophosphate (PI4P). The localization and roles of both PI(4,5)P2 and PI4P are well established, is the broadly accepted methodological approach for their immunocytochemical visualization in different cell compartments in several cell lines. However, not much is known about these PIs in platelets (PLTs), the smallest blood cells that detect vessel wall injury, activate, and stop the bleeding. Therefore, we sought to investigate the localization of PI(4,5)P2 and PI4P in resting and activated PLTs by antibody staining. Here, we show that the intracellular pools of PI(4,5)P2 and PI4P can be detected by the established staining protocol, and these pools can be modulated by inhibitors of OCRL phosphatase and PI4KIIIα kinase. However, although resting PLTs readily stain for the plasma membrane (PM) pools of PI(4,5)P2 and PI4P, just a few activated cells were stained with the established protocol. We show that optimized protocol allows for the visualization of PI(4,5)P2 and PI4P at PM in activated PLTs, which could also be modulated by OCRL and PI4KIIIα inhibitors. We conclude that PI(4,5)P2 and PI4P are more sensitive to lipid extraction by permeabilizing agents in activated than in resting human PLTs, which suggests their different roles during PLT activation.
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61
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Schink KO, Tan KW, Spangenberg H, Martorana D, Sneeggen M, Stévenin V, Enninga J, Campsteijn C, Raiborg C, Stenmark H. The phosphoinositide coincidence detector Phafin2 promotes macropinocytosis by coordinating actin organisation at forming macropinosomes. Nat Commun 2021; 12:6577. [PMID: 34772942 PMCID: PMC8590015 DOI: 10.1038/s41467-021-26775-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/08/2021] [Indexed: 01/14/2023] Open
Abstract
Uptake of large volumes of extracellular fluid by actin-dependent macropinocytosis has an important role in infection, immunity and cancer development. A key question is how actin assembly and disassembly are coordinated around macropinosomes to allow them to form and subsequently pass through the dense actin network underlying the plasma membrane to move towards the cell center for maturation. Here we show that the PH and FYVE domain protein Phafin2 is recruited transiently to newly-formed macropinosomes by a mechanism that involves coincidence detection of PtdIns3P and PtdIns4P. Phafin2 also interacts with actin via its PH domain, and recruitment of Phafin2 coincides with actin reorganization around nascent macropinosomes. Moreover, forced relocalization of Phafin2 to the plasma membrane causes rearrangement of the subcortical actin cytoskeleton. Depletion of Phafin2 inhibits macropinosome internalization and maturation and prevents KRAS-transformed cancer cells from utilizing extracellular protein as an amino acid source. We conclude that Phafin2 promotes macropinocytosis by controlling timely delamination of actin from nascent macropinosomes for their navigation through the dense subcortical actin network.
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Affiliation(s)
- Kay Oliver Schink
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway.
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway.
| | - Kia Wee Tan
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway
| | - Hélène Spangenberg
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway
| | - Domenica Martorana
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway
| | - Marte Sneeggen
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway
| | - Virginie Stévenin
- Department of Cell and Chemical Biology, Leiden University Medical Center, Einthovenweg 20, 2333 ZC, Leiden, The Netherlands
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Jost Enninga
- Institut Pasteur, Dynamics of Host-Pathogen Interactions Unit, 25 Rue du Dr. Roux, Paris, France
| | - Coen Campsteijn
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, PO Box 1112 Blindern, 0317, Oslo, Norway
| | - Camilla Raiborg
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Montebello, N-0379, Oslo, Norway.
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Montebello, 0379, Oslo, Norway.
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62
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Verdura E, Rodríguez-Palmero A, Vélez-Santamaria V, Planas-Serra L, de la Calle I, Raspall-Chaure M, Roubertie A, Benkirane M, Saettini F, Pavinato L, Mandrile G, O'Leary M, O'Heir E, Barredo E, Chacón A, Michaud V, Goizet C, Ruiz M, Schlüter A, Rouvet I, Sala-Coromina J, Fossati C, Iascone M, Canonico F, Marcé-Grau A, de Souza P, Adams DR, Casasnovas C, Rehm HL, Mefford HC, González Gutierrez-Solana L, Brusco A, Koenig M, Macaya A, Pujol A. Biallelic PI4KA variants cause a novel neurodevelopmental syndrome with hypomyelinating leukodystrophy. Brain 2021; 144:2659-2669. [PMID: 34415322 PMCID: PMC8557332 DOI: 10.1093/brain/awab124] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/10/2021] [Accepted: 02/15/2021] [Indexed: 11/14/2022] Open
Abstract
Phosphoinositides are lipids that play a critical role in processes such as cellular signalling, ion channel activity and membrane trafficking. When mutated, several genes that encode proteins that participate in the metabolism of these lipids give rise to neurological or developmental phenotypes. PI4KA is a phosphoinositide kinase that is highly expressed in the brain and is essential for life. Here we used whole exome or genome sequencing to identify 10 unrelated patients harbouring biallelic variants in PI4KA that caused a spectrum of conditions ranging from severe global neurodevelopmental delay with hypomyelination and developmental brain abnormalities to pure spastic paraplegia. Some patients presented immunological deficits or genito-urinary abnormalities. Functional analyses by western blotting and immunofluorescence showed decreased PI4KA levels in the patients’ fibroblasts. Immunofluorescence and targeted lipidomics indicated that PI4KA activity was diminished in fibroblasts and peripheral blood mononuclear cells. In conclusion, we report a novel severe metabolic disorder caused by PI4KA malfunction, highlighting the importance of phosphoinositide signalling in human brain development and the myelin sheath.
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Affiliation(s)
- Edgard Verdura
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Agustí Rodríguez-Palmero
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Pediatric Neurology Unit, Department of Pediatrics, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, Catalonia, Spain
| | - Valentina Vélez-Santamaria
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Neuromuscular Unit, Neurology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Laura Planas-Serra
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Irene de la Calle
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain
| | - Miquel Raspall-Chaure
- Neurology Research Group, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.,Department of Paediatric Neurology, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Agathe Roubertie
- Département de Neuropédiatrie, Hôpital Gui de Chauliac Pôle Neurosciences Tête et Cou, Montpellier, France.,INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, France
| | - Mehdi Benkirane
- Laboratoire de Génétique de Maladies Rares EA7402, Institut Universitaire de Recherche Clinique, Université de Montpellier, CHU Montpellier, CEDEX 5, 34295 Montpellier, France
| | - Francesco Saettini
- Paediatric Hematology Department, Fondazione MBBM, University of Milano Bicocca, Monza, Italy
| | - Lisa Pavinato
- Department of Medical Sciences, University of Torino, 10126 Torino, Italy
| | - Giorgia Mandrile
- Thalassemia Centre and Medical Genetics Unit, San Luigi Gonzaga University Hospital, Orbassano, Italy
| | - Melanie O'Leary
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Emily O'Heir
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Estibaliz Barredo
- Neuropediatric Department, Hospital Universitario Gregorio Marañón, Madrid, Spain
| | - Almudena Chacón
- Neuropediatric Department, Hospital Universitario Gregorio Marañón, Madrid, Spain
| | - Vincent Michaud
- Molecular Genetics Laboratory, Bordeaux University Hospital, Bordeaux, Aquitaine, France.,INSERM U1211, Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Talence, Aquitaine, France
| | - Cyril Goizet
- INSERM U1211, Rare Diseases Laboratory: Genetics and Metabolism, University of Bordeaux, Talence, Aquitaine, France.,Reference Center for Rare Neurogenetic Diseases, Department of Medical Genetics, University Hospital Centre Bordeaux Pellegrin Hospital Group, Bordeaux, Aquitaine, France
| | - Montserrat Ruiz
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Agatha Schlüter
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Isabelle Rouvet
- Cellular Biotechnology Department and Biobank, Hospices Civils de Lyon, CHU de Lyon, Lyon, France
| | - Julia Sala-Coromina
- Neurology Research Group, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.,Department of Paediatric Neurology, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Chiara Fossati
- Department of Paediatrics, Fondazione MBBM, Monza, Italy
| | - Maria Iascone
- Molecular Genetics Laboratory, USSD LGM, Papa Giovanni XXIII Hospital, Bergamo, Italy
| | - Francesco Canonico
- Department of Neuroradiology, University of Milan-Bicocca, San Gerardo Hospital, ASST di Monza, Monza, Italy
| | - Anna Marcé-Grau
- Neurology Research Group, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Precilla de Souza
- Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - David R Adams
- Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD, USA.,Undiagnosed Diseases Program, The Common Fund, NIH, Bethesda, MD, USA
| | - Carlos Casasnovas
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain.,Neuromuscular Unit, Neurology Department, Hospital Universitari de Bellvitge, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Heidi L Rehm
- Center for Mendelian Genomics, Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Paediatrics, University of Washington, Seattle, WA 98195, USA
| | - Luis González Gutierrez-Solana
- Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain.,Pediatric Neurology, Hospital Infantil Universitario Niño Jesús, Madrid, Spain
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, 10126 Torino, Italy.,Medical Genetics Unit, Città della Salute e della Scienza, University Hospital, 10126 Turin, Italy
| | - Michel Koenig
- Laboratoire de Génétique de Maladies Rares EA7402, Institut Universitaire de Recherche Clinique, Université de Montpellier, CHU Montpellier, CEDEX 5, 34295 Montpellier, France
| | - Alfons Macaya
- Neurology Research Group, Vall d'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain.,Department of Paediatric Neurology, Vall d'Hebron University Hospital, Barcelona, Spain
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Barcelona, Catalonia, Spain.,Centre for Biomedical Research in Network on Rare Diseases (CIBERER), Instituto de Salud Carlos III, 28029, Madrid, Spain.,Catalan Institution of Research and Advanced Studies (ICREA), Barcelona, Catalonia, Spain
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63
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Ulengin-Talkish I, Parson MAH, Jenkins ML, Roy J, Shih AZL, St-Denis N, Gulyas G, Balla T, Gingras AC, Várnai P, Conibear E, Burke JE, Cyert MS. Palmitoylation targets the calcineurin phosphatase to the phosphatidylinositol 4-kinase complex at the plasma membrane. Nat Commun 2021; 12:6064. [PMID: 34663815 PMCID: PMC8523714 DOI: 10.1038/s41467-021-26326-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/29/2021] [Indexed: 11/25/2022] Open
Abstract
Calcineurin, the conserved protein phosphatase and target of immunosuppressants, is a critical mediator of Ca2+ signaling. Here, to discover calcineurin-regulated processes we examined an understudied isoform, CNAβ1. We show that unlike canonical cytosolic calcineurin, CNAβ1 localizes to the plasma membrane and Golgi due to palmitoylation of its divergent C-terminal tail, which is reversed by the ABHD17A depalmitoylase. Palmitoylation targets CNAβ1 to a distinct set of membrane-associated interactors including the phosphatidylinositol 4-kinase (PI4KA) complex containing EFR3B, PI4KA, TTC7B and FAM126A. Hydrogen-deuterium exchange reveals multiple calcineurin-PI4KA complex contacts, including a calcineurin-binding peptide motif in the disordered tail of FAM126A, which we establish as a calcineurin substrate. Calcineurin inhibitors decrease PI4P production during Gq-coupled GPCR signaling, suggesting that calcineurin dephosphorylates and promotes PI4KA complex activity. In sum, this work discovers a calcineurin-regulated signaling pathway which highlights the PI4KA complex as a regulatory target and reveals that dynamic palmitoylation confers unique localization, substrate specificity and regulation to CNAβ1.
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Affiliation(s)
| | - Matthew A H Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Jagoree Roy
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Alexis Z L Shih
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
- Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Nicole St-Denis
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, University of Toronto, Toronto, Canada
- High-Fidelity Science Communications, Summerside, PE, Canada
| | - Gergo Gulyas
- Section on Molecular Signal Transduction, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Anne-Claude Gingras
- Lunenfeld-Tanenbaum Research Institute at Mount Sinai Hospital, University of Toronto, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Péter Várnai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Elizabeth Conibear
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
- Department of Biochemistry, The University of British Columbia, Vancouver, BC, Canada
| | - Martha S Cyert
- Department of Biology, Stanford University, Stanford, CA, USA.
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64
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Li YP, Mikrani R, Hu YF, Faran Ashraf Baig MM, Abbas M, Akhtar F, Xu M. Research progress of phosphatidylinositol 4-kinase and its inhibitors in inflammatory diseases. Eur J Pharmacol 2021; 907:174300. [PMID: 34217706 DOI: 10.1016/j.ejphar.2021.174300] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 06/24/2021] [Accepted: 06/30/2021] [Indexed: 01/08/2023]
Abstract
Phosphatidylinositol 4-kinase (PI4K) is a lipid kinase that can catalyze the transfer of phosphate group from ATP to the inositol ring of phosphatidylinositol (PtdIns) resulting in the phosphorylation of PtdIns at 4-OH sites, to generate phosphatidylinositol 4-phosphate (PI4P). Studies on biological functions reveal that PI4K is closely related to the occurrence and development of various inflammatory diseases such as obesity, cancer, viral infections, malaria, Alzheimer's disease, etc. PI4K-related inhibitors have been found to have the effects of inhibiting virus replication, anti-cancer, treating malaria and reducing rejection in organ transplants, among which MMV390048, an anti-malaria drug, has entered phase II clinical trial. This review discusses the classification, structure, distribution and related inhibitors of PI4K and their role in the progression of cancer, viral replication, and other inflammation induced diseases to explore their potential as therapeutic targets.
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Affiliation(s)
- Yan-Ping Li
- Department of Clinical Pharmacy, School of Preclinical Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Reyaj Mikrani
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria 3052, Australia
| | - Yi-Fan Hu
- Department of Clinical Pharmacy, School of Preclinical Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Mirza Muhammad Faran Ashraf Baig
- Laboratory of Biomedical Engineering for Novel Bio-functional and Pharmaceutical Nano-materials, Prince Philip Dental Hospital, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, 999077, China
| | - Muhammad Abbas
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210023, PR China
| | - Fahad Akhtar
- State Key Laboratory of Molecular Development Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China; School of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ming Xu
- Department of Clinical Pharmacy, School of Preclinical Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
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65
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Oncogenic KRAS is dependent upon an EFR3A-PI4KA signaling axis for potent tumorigenic activity. Nat Commun 2021; 12:5248. [PMID: 34504076 PMCID: PMC8429657 DOI: 10.1038/s41467-021-25523-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/10/2021] [Indexed: 11/15/2022] Open
Abstract
The HRAS, NRAS, and KRAS genes are collectively mutated in a fifth of all human cancers. These mutations render RAS GTP-bound and active, constitutively binding effector proteins to promote signaling conducive to tumorigenic growth. To further elucidate how RAS oncoproteins signal, we mined RAS interactomes for potential vulnerabilities. Here we identify EFR3A, an adapter protein for the phosphatidylinositol kinase PI4KA, to preferentially bind oncogenic KRAS. Disrupting EFR3A or PI4KA reduces phosphatidylinositol-4-phosphate, phosphatidylserine, and KRAS levels at the plasma membrane, as well as oncogenic signaling and tumorigenesis, phenotypes rescued by tethering PI4KA to the plasma membrane. Finally, we show that a selective PI4KA inhibitor augments the antineoplastic activity of the KRASG12C inhibitor sotorasib, suggesting a clinical path to exploit this pathway. In sum, we have discovered a distinct KRAS signaling axis with actionable therapeutic potential for the treatment of KRAS-mutant cancers. The lipid composition of the plasma membrane defines the localisation of KRAS and its oncogenic function. Here the authors show that EFR3A binds to active KRAS to recruit PI4KA and alters the lipid composition of the plasma membrane to promote KRAS oncogenic signalling and tumorigenesis.
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66
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Myeong J, de la Cruz L, Jung SR, Yeon JH, Suh BC, Koh DS, Hille B. Phosphatidylinositol 4,5-bisphosphate is regenerated by speeding of the PI 4-kinase pathway during long PLC activation. J Gen Physiol 2021; 152:211533. [PMID: 33186442 PMCID: PMC7671494 DOI: 10.1085/jgp.202012627] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 10/13/2020] [Indexed: 01/05/2023] Open
Abstract
The dynamic metabolism of membrane phosphoinositide lipids involves several cellular compartments including the ER, Golgi, and plasma membrane. There are cycles of phosphorylation and dephosphorylation and of synthesis, transfer, and breakdown. The simplified phosphoinositide cycle comprises synthesis of phosphatidylinositol in the ER, transport, and phosphorylation in the Golgi and plasma membranes to generate phosphatidylinositol 4,5-bisphosphate, followed by receptor-stimulated hydrolysis in the plasma membrane and return of the components to the ER for reassembly. Using probes for specific lipid species, we have followed and analyzed the kinetics of several of these events during stimulation of M1 muscarinic receptors coupled to the G-protein Gq. We show that during long continued agonist action, polyphosphorylated inositol lipids are initially depleted but then regenerate while agonist is still present. Experiments and kinetic modeling reveal that the regeneration results from gradual but massive up-regulation of PI 4-kinase pathways rather than from desensitization of receptors. Golgi pools of phosphatidylinositol 4-phosphate and the lipid kinase PI4KIIIα (PI4KA) contribute to this homeostatic regeneration. This powerful acceleration, which may be at the level of enzyme activity or of precursor and product delivery, reveals strong regulatory controls in the phosphoinositide cycle.
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Affiliation(s)
- Jongyun Myeong
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA
| | - Lizbeth de la Cruz
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA
| | | | - Jun-Hee Yeon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Byung-Chang Suh
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea
| | - Duk-Su Koh
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA
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67
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Salter CG, Cai Y, Lo B, Helman G, Taylor H, McCartney A, Leslie JS, Accogoli A, Zara F, Traverso M, Fasham J, Lees JA, Ferla M, Chioza BA, Wenger O, Scott E, Cross HE, Crawford J, Warshawsky I, Keisling M, Agamanolis D, Melver CW, Cox H, Elawad M, Marton T, Wakeling M, Holzinger D, Tippelt S, Munteanu M, Valcheva D, Deal C, Van Meerbeke S, Vockley CW, Butte MJ, Acar U, van der Knaap MS, Korenke GC, Kotzaeridou U, Balla T, Simons C, Uhlig HH, Crosby AH, De Camilli P, Wolf NI, Baple EL. Biallelic PI4KA variants cause neurological, intestinal and immunological disease. Brain 2021; 144:3597-3610. [PMID: 34415310 PMCID: PMC8719846 DOI: 10.1093/brain/awab313] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 07/14/2021] [Accepted: 08/01/2021] [Indexed: 11/22/2022] Open
Abstract
Phosphatidylinositol 4-kinase IIIα (PI4KIIIα/PI4KA/OMIM:600286) is a lipid kinase generating phosphatidylinositol 4-phosphate (PI4P), a membrane phospholipid with critical roles in the physiology of multiple cell types. PI4KIIIα’s role in PI4P generation requires its assembly into a heterotetrameric complex with EFR3, TTC7 and FAM126. Sequence alterations in two of these molecular partners, TTC7 (encoded by TTC7A or TCC7B) and FAM126, have been associated with a heterogeneous group of either neurological (FAM126A) or intestinal and immunological (TTC7A) conditions. Here we show that biallelic PI4KA sequence alterations in humans are associated with neurological disease, in particular hypomyelinating leukodystrophy. In addition, affected individuals may present with inflammatory bowel disease, multiple intestinal atresia and combined immunodeficiency. Our cellular, biochemical and structural modelling studies indicate that PI4KA-associated phenotypical outcomes probably stem from impairment of PI4KIIIα-TTC7-FAM126's organ-specific functions, due to defective catalytic activity or altered intra-complex functional interactions. Together, these data define PI4KA gene alteration as a cause of a variable phenotypical spectrum and provide fundamental new insight into the combinatorial biology of the PI4KIIIα-FAM126-TTC7-EFR3 molecular complex.
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Affiliation(s)
- Claire G Salter
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, UK.,Wessex Clinical Genetics Service, Princess Anne Hospital, Southampton, UK
| | - Yiying Cai
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.,Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | - Bernice Lo
- Research Branch, Sidra Medicine, Doha, Qatar.,College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Guy Helman
- Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville, Melbourne, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Henry Taylor
- Department of surgery and Cancer, Imperial College London, London, UK
| | - Amber McCartney
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.,Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | - Joseph S Leslie
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, UK
| | | | | | | | - James Fasham
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, UK.,Peninsula Clinical Genetics Service, Royal Devon and Exeter Hospital, Exeter, UK
| | - Joshua A Lees
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Matteo Ferla
- Wellcome Centre Human Genetics, University of Oxford, Oxford, UK
| | - Barry A Chioza
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, UK
| | | | | | - Harold E Cross
- Department of Ophthalmology, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Joanna Crawford
- Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville, Melbourne, Australia
| | | | | | | | | | - Helen Cox
- West Midlands Clinical Genetics Service, Birmingham Women's Hospital, Birmingham, UK
| | - Mamoun Elawad
- Department of Gastroenterology, Sidra Medicine, Doha, Qatar
| | - Tamas Marton
- West Midlands Perinatal Pathology, Birmingham Women's Hospital, Edgbaston, Birmingham, UK
| | - Matthew Wakeling
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, UK
| | - Dirk Holzinger
- Department of Pediatric Haematology-Oncology, University of Duisburg-Essen, Essen, Germany
| | - Stephan Tippelt
- Department of Pediatric Haematology-Oncology, University of Duisburg-Essen, Essen, Germany
| | - Martin Munteanu
- Institute for Human Genetics, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | | | - Christin Deal
- Children's Hospital of Pittsburgh, UPMC, Division of Pediatric Allergy and Immunology, Pittsburgh, USA
| | - Sara Van Meerbeke
- Children's Hospital of Pittsburgh, UPMC, Division of Pediatric Allergy and Immunology, Pittsburgh, USA
| | - Catherine Walsh Vockley
- Children's Hospital of Pittsburgh, UPMC, Division of Genetic and Genomic Medicine, Pittsburgh, USA
| | - Manish J Butte
- Department of Paediatrics, Division of Immunology, Allergy, and Rheumatology, UCLA, Los Angeles, CA, USA
| | - Utkucan Acar
- Department of Paediatrics, Division of Immunology, Allergy, and Rheumatology, UCLA, Los Angeles, CA, USA
| | - Marjo S van der Knaap
- Amsterdam Leukodystrophy Center, Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Center, VU University Amsterdam and Amsterdam Neuroscience, 1081 HV Amsterdam, The Netherlands.,Department of Functional Genomics, Centre for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - G Christoph Korenke
- Department of Neuropediatrics, University Children's Hospital, Klinikum Oldenburg, 26133 Oldenburg, Germany
| | - Urania Kotzaeridou
- Department of Child Neurology and Metabolic Medicine, Center for Pediatric and Adolescent Medicine, University Hospital Heidelberg, D-69120 Heidelberg, Germany
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Cas Simons
- Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville, Melbourne, Australia.,Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
| | - Holm H Uhlig
- Translational Gastroenterology Unit, NIHR Oxford Biomedical Research Centre, John Radcliffe Hospital, University of Oxford, Oxfordshire, UK.,Department of Paediatrics, University of Oxford, Oxfordshire, UK.,Oxford NIHR Biomedical Research Centre, Oxford, UK
| | - Andrew H Crosby
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, UK
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.,Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Nicole I Wolf
- Amsterdam Leukodystrophy Center, Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Center, VU University Amsterdam and Amsterdam Neuroscience, 1081 HV Amsterdam, The Netherlands.,Department of Functional Genomics, Centre for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, The Netherlands
| | - Emma L Baple
- RILD Wellcome Wolfson Centre, University of Exeter Medical School, Exeter, UK.,Peninsula Clinical Genetics Service, Royal Devon and Exeter Hospital, Exeter, UK
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Nakamura TS, Suda Y, Muneshige K, Fujieda Y, Okumura Y, Inoue I, Tanaka T, Takahashi T, Nakanishi H, Gao XD, Okada Y, Neiman AM, Tachikawa H. Suppression of Vps13 adaptor protein mutants reveals a central role for PI4P in regulating prospore membrane extension. PLoS Genet 2021; 17:e1009727. [PMID: 34407079 PMCID: PMC8372973 DOI: 10.1371/journal.pgen.1009727] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/20/2021] [Indexed: 01/19/2023] Open
Abstract
Vps13 family proteins are proposed to function in bulk lipid transfer between membranes, but little is known about their regulation. During sporulation of Saccharomyces cerevisiae, Vps13 localizes to the prospore membrane (PSM) via the Spo71–Spo73 adaptor complex. We previously reported that loss of any of these proteins causes PSM extension and subsequent sporulation defects, yet their precise function remains unclear. Here, we performed a genetic screen and identified genes coding for a fragment of phosphatidylinositol (PI) 4-kinase catalytic subunit and PI 4-kinase noncatalytic subunit as multicopy suppressors of spo73Δ. Further genetic and cytological analyses revealed that lowering PI4P levels in the PSM rescues the spo73Δ defects. Furthermore, overexpression of VPS13 and lowering PI4P levels synergistically rescued the defect of a spo71Δ spo73Δ double mutant, suggesting that PI4P might regulate Vps13 function. In addition, we show that an N-terminal fragment of Vps13 has affinity for the endoplasmic reticulum (ER), and ER-plasma membrane (PM) tethers localize along the PSM in a manner dependent on Vps13 and the adaptor complex. These observations suggest that Vps13 and the adaptor complex recruit ER-PM tethers to ER-PSM contact sites. Our analysis revealed that involvement of a phosphoinositide, PI4P, in regulation of Vps13, and also suggest that distinct contact site proteins function cooperatively to promote de novo membrane formation. Vps13 family proteins are conserved lipid transfer proteins that function at organelle contact sites and have been implicated in a number of different neurological diseases. In the yeast Saccharomyces cerevisiae, Vps13 is encoded by a single gene and is localized to various contact sites by interaction with different adaptor proteins and/or lipids, however its regulation is yet to be clarified. We have previously shown that during the developmental process of sporulation, Vps13 is recruited to de novo membrane structures called prospore membranes (PSMs) by a specific adaptor complex, and Vps13 and its adaptors are required for PSM extension. Here we reveal that loss of an adaptor can be overcome by lowering phosphatidylinositol-4-phosphate (PI4P) levels, either by inhibiting PI 4-kinase on the PSM or recruiting PI 4-phospatase to the PSM and that PI4P levels in the PSM affect Vps13 function. Further, we show that Vps13 forms endoplasmic reticulum (ER)-PSM contact sites, that ER-plasma membrane tethering proteins are recruited to ER-PSM contacts, and these proteins may function in conjunction with Vps13. Thus, our work shines light on both the mechanisms of intracellular remodeling and the function of this important class of lipid transfer proteins.
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Affiliation(s)
- Tsuyoshi S. Nakamura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan
| | - Yasuyuki Suda
- Department of Molecular Cell Biology, Graduate School of Comprehensive Human Sciences and Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan
| | - Kenji Muneshige
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuji Fujieda
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuuya Okumura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Ichiro Inoue
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takayuki Tanaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Tetsuo Takahashi
- Laboratory of Glycobiology and Glycotechnology, Department of Applied Biochemistry, School of Engineering, Tokai University, Kanagawa, Japan
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yasushi Okada
- Laboratory for Cell Dynamics Observation, Center for Biosystems Dynamics Research, RIKEN, Osaka, Japan
- Department of Physics and Universal Biology Institute, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Department of Physics, Universal Biology Institute, and the International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo, Tokyo, Japan
| | - Aaron M. Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Hiroyuki Tachikawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
- * E-mail:
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69
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Inhibition of phosphatidylinositol kinase-III alpha induces or facilitates lysosome exocytosis from microglia. Neuroreport 2021; 31:697-701. [PMID: 32427802 DOI: 10.1097/wnr.0000000000001348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Besides degradation, lysosomes can also carry molecules for secretion out of the cell, such as ATP and cytokines, during unconventional secretion. Phosphatidylinositols and their metabolizing enzymes play important roles in the sorting and trafficking of lysosomal materials through the trans-Golgi network. The present study reveals a new function of phosphatidylinositol kinase-III alpha in the 'kiss-and-run' fusion of lysosomes at the plasma membrane to release ATP from microglia.
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70
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Compartmentalization of phosphatidylinositol 4,5-bisphosphate metabolism into plasma membrane liquid-ordered/raft domains. Proc Natl Acad Sci U S A 2021; 118:2025343118. [PMID: 33619111 DOI: 10.1073/pnas.2025343118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Possible segregation of plasma membrane (PM) phosphoinositide metabolism in membrane lipid domains is not fully understood. We exploited two differently lipidated peptide sequences, L10 and S15, to mark liquid-ordered, cholesterol-rich (Lo) and liquid-disordered, cholesterol-poor (Ld) domains of the PM, often called raft and nonraft domains, respectively. Imaging of the fluorescent labels verified that L10 segregated into cholesterol-rich Lo phases of cooled giant plasma-membrane vesicles (GPMVs), whereas S15 and the dye FAST DiI cosegregated into cholesterol-poor Ld phases. The fluorescent protein markers were used as Förster resonance energy transfer (FRET) pairs in intact cells. An increase of homologous FRET between L10 probes showed that depleting membrane cholesterol shrank Lo domains and enlarged Ld domains, whereas a decrease of L10 FRET showed that adding more cholesterol enlarged Lo and shrank Ld Heterologous FRET signals between the lipid domain probes and phosphoinositide marker proteins suggested that phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P 2] and phosphatidylinositol 4-phosphate (PtdIns4P) are present in both Lo and Ld domains. In kinetic analysis, muscarinic-receptor-activated phospholipase C (PLC) depleted PtdIns(4,5)P 2 and PtdIns4P more rapidly and produced diacylglycerol (DAG) more rapidly in Lo than in Ld Further, PtdIns(4,5)P 2 was restored more rapidly in Lo than in Ld Thus destruction and restoration of PtdIns(4,5)P 2 are faster in Lo than in Ld This suggests that Lo is enriched with both the receptor G protein/PLC pathway and the PtdIns/PI4-kinase/PtdIns4P pathway. The significant kinetic differences of lipid depletion and restoration also mean that exchange of lipids between these domains is much slower than free diffusion predicts.
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71
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Nakatsu F, Kawasaki A. Functions of Oxysterol-Binding Proteins at Membrane Contact Sites and Their Control by Phosphoinositide Metabolism. Front Cell Dev Biol 2021; 9:664788. [PMID: 34249917 PMCID: PMC8264513 DOI: 10.3389/fcell.2021.664788] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 05/06/2021] [Indexed: 01/10/2023] Open
Abstract
Lipids must be correctly transported within the cell to the right place at the right time in order to be fully functional. Non-vesicular lipid transport is mediated by so-called lipid transfer proteins (LTPs), which contain a hydrophobic cavity that sequesters lipid molecules. Oxysterol-binding protein (OSBP)-related proteins (ORPs) are a family of LTPs known to harbor lipid ligands, such as cholesterol and phospholipids. ORPs act as a sensor or transporter of those lipid ligands at membrane contact sites (MCSs) where two different cellular membranes are closely apposed. In particular, a characteristic functional property of ORPs is their role as a lipid exchanger. ORPs mediate counter-directional transport of two different lipid ligands at MCSs. Several, but not all, ORPs transport their lipid ligand from the endoplasmic reticulum (ER) in exchange for phosphatidylinositol 4-phosphate (PI4P), the other ligand, on apposed membranes. This ORP-mediated lipid “countertransport” is driven by the concentration gradient of PI4P between membranes, which is generated by its kinases and phosphatases. In this review, we will discuss how ORP function is tightly coupled to metabolism of phosphoinositides such as PI4P. Recent progress on the role of ORP-mediated lipid transport/countertransport at multiple MCSs in cellular functions will be also discussed.
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Affiliation(s)
- Fubito Nakatsu
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
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72
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Emerging Prospects for Combating Fungal Infections by Targeting Phosphatidylinositol Transfer Proteins. Int J Mol Sci 2021; 22:ijms22136754. [PMID: 34201733 PMCID: PMC8269425 DOI: 10.3390/ijms22136754] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/11/2021] [Accepted: 06/11/2021] [Indexed: 12/27/2022] Open
Abstract
The emergence of fungal “superbugs” resistant to the limited cohort of anti-fungal agents available to clinicians is eroding our ability to effectively treat infections by these virulent pathogens. As the threat of fungal infection is escalating worldwide, this dwindling response capacity is fueling concerns of impending global health emergencies. These developments underscore the urgent need for new classes of anti-fungal drugs and, therefore, the identification of new targets. Phosphoinositide signaling does not immediately appear to offer attractive targets due to its evolutionary conservation across the Eukaryota. However, recent evidence argues otherwise. Herein, we discuss the evidence identifying Sec14-like phosphatidylinositol transfer proteins (PITPs) as unexplored portals through which phosphoinositide signaling in virulent fungi can be chemically disrupted with exquisite selectivity. Recent identification of lead compounds that target fungal Sec14 proteins, derived from several distinct chemical scaffolds, reveals exciting inroads into the rational design of next generation Sec14 inhibitors. Development of appropriately refined next generation Sec14-directed inhibitors promises to expand the chemical weaponry available for deployment in the shifting field of engagement between fungal pathogens and their human hosts.
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73
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The distribution of phosphatidylinositol 4,5-bisphosphate in the budding yeast plasma membrane. Histochem Cell Biol 2021; 156:109-121. [PMID: 34052862 DOI: 10.1007/s00418-021-01989-8] [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] [Accepted: 04/17/2021] [Indexed: 01/07/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) is generated through phosphorylation of phosphatidylinositol 4-phosphate (PtdIns(4)P) by Mss4p, the only PtdIns phosphate 5-kinase in yeast cells. PtdIns(4,5)P2 is involved in various kinds of yeast functions. PtdIns(4)P is not only the immediate precursor of PtdIns(4,5)P2, but also an essential signaling molecule in the plasma membrane, Golgi, and endosomal system. To analyze the distribution of PtdIns(4,5)P2 and PtdIns(4)P in the yeast plasma membrane at a nanoscale level, we employed a freeze-fracture electron microscopy (EM) method that physically immobilizes lipid molecules in situ. It has been reported that the plasma membrane of budding yeast can be divided into three distinct areas: furrowed, hexagonal, and undifferentiated flat. Previously, using the freeze-fracture EM method, we determined that PtdIns(4)P is localized in the undifferentiated flat area, avoiding the furrowed and hexagonal areas of the plasma membrane. In the present study, we found that PtdIns(4,5)P2 was localized in the cytoplasmic leaflet of the plasma membrane, and concentrated in the furrowed area. There are three types of PtdIns 4-kinases which are encoded by stt4, pik1, and lsb6. The labeling density of PtdIns(4)P in the plasma membrane significantly decreased in both pik1ts and stt4ts mutants. However, the labeling densities of PtdIns(4,5)P2 in the plasma membrane of both the pik1ts and stt4ts mutants were comparable to that of the wild type yeast. These results suggest that PtdIns(4)P produced by either Pik1p or Stt4p is immediately phosphorylated by Mss4p and converted to PtdIns(4,5)P2 at the plasma membrane.
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74
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Batrouni AG, Baskin JM. The chemistry and biology of phosphatidylinositol 4-phosphate at the plasma membrane. Bioorg Med Chem 2021; 40:116190. [PMID: 33965837 DOI: 10.1016/j.bmc.2021.116190] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 12/29/2022]
Abstract
Phosphoinositides are an important class of anionic, low abundance signaling lipids distributed throughout intracellular membranes. The plasma membrane contains three phosphoinositides: PI(4)P, PI(4,5)P2, and PI(3,4,5)P3. Of these, PI(4)P has remained the most mysterious, despite its characterization in this membrane more than a half-century ago. Fortunately, recent methodological innovations at the chemistry-biology interface have spurred a renaissance of interest in PI(4)P. Here, we describe these new toolsets and how they have revealed novel functions for the plasma membrane PI(4)P pool. We examine high-resolution structural characterization of the plasma membrane PI 4-kinase complex that produces PI(4)P, tools for modulating PI(4)P levels including isoform-selective PI 4-kinase inhibitors, and fluorescent probes for visualizing PI(4)P. Collectively, these chemical and biochemical approaches have revealed insights into how cells regulate synthesis of PI(4)P and its downstream metabolites as well as new roles for plasma membrane PI(4)P in non-vesicular lipid transport, membrane homeostasis and trafficking, and cell signaling pathways.
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Affiliation(s)
- Alex G Batrouni
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Jeremy M Baskin
- Department of Chemistry and Chemical Biology and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA.
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75
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Haeussler S, Yeroslaviz A, Rolland SG, Luehr S, Lambie EJ, Conradt B. Genome-wide RNAi screen for regulators of UPRmt in Caenorhabditis elegans mutants with defects in mitochondrial fusion. G3-GENES GENOMES GENETICS 2021; 11:6204483. [PMID: 33784383 PMCID: PMC8495942 DOI: 10.1093/g3journal/jkab095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 03/18/2021] [Indexed: 01/22/2023]
Abstract
Mitochondrial dynamics plays an important role in mitochondrial quality control and the adaptation of metabolic activity in response to environmental changes. The disruption of mitochondrial dynamics has detrimental consequences for mitochondrial and cellular homeostasis and leads to the activation of the mitochondrial unfolded protein response (UPRmt), a quality control mechanism that adjusts cellular metabolism and restores homeostasis. To identify genes involved in the induction of UPRmt in response to a block in mitochondrial fusion, we performed a genome-wide RNAi screen in Caenorhabditis elegans mutants lacking the gene fzo-1, which encodes the ortholog of mammalian Mitofusin, and identified 299 suppressors and 86 enhancers. Approximately 90% of these 385 genes are conserved in humans, and one third of the conserved genes have been implicated in human disease. Furthermore, many have roles in developmental processes, which suggests that mitochondrial function and the response to stress are defined during development and maintained throughout life. Our dataset primarily contains mitochondrial enhancers and non-mitochondrial suppressors of UPRmt, indicating that the maintenance of mitochondrial homeostasis has evolved as a critical cellular function, which, when disrupted, can be compensated for by many different cellular processes. Analysis of the subsets 'non-mitochondrial enhancers' and 'mitochondrial suppressors' suggests that organellar contact sites, especially between the ER and mitochondria, are of importance for mitochondrial homeostasis. In addition, we identified several genes involved in IP3 signaling that modulate UPRmt in fzo-1 mutants and found a potential link between pre-mRNA splicing and UPRmt activation.
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Affiliation(s)
- Simon Haeussler
- Faculty of Biology, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Assa Yeroslaviz
- Computational Biology Group, Max Planck Institute of Biochemistry, 82152 Planegg-Martinsried, Germany
| | - Stéphane G Rolland
- Faculty of Biology, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany.,Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan 44919, South Korea
| | - Sebastian Luehr
- Faculty of Biology, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Eric J Lambie
- Center for Integrated Protein Science, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Barbara Conradt
- Faculty of Biology, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany.,Center for Integrated Protein Science, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany.,Research Department of Cell and Developmental Biology, Division of Biosciences, University College London, London WC1E 6AP, United Kingdom
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76
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Baba T, Balla T. Emerging roles of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate as regulators of multiple steps in autophagy. J Biochem 2021; 168:329-336. [PMID: 32745205 DOI: 10.1093/jb/mvaa089] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/17/2020] [Indexed: 12/13/2022] Open
Abstract
Inositol phospholipids are low-abundance regulatory lipids that orchestrate diverse cellular functions in eukaryotic organisms. Recent studies have uncovered involvement of the lipids in multiple steps in autophagy. The late endosome-lysosome compartment plays critical roles in cellular nutrient sensing and in the control of both the initiation of autophagy and the late stage of eventual degradation of cytosolic materials destined for elimination. It is particularly notable that inositol lipids are involved in almost all steps of the autophagic process. In this review, we summarize how inositol lipids regulate and contribute to autophagy through the endomembrane compartments, primarily focusing on PI4P and PI(4,5)P2.
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Affiliation(s)
- Takashi Baba
- Department of Biological Informatics and Experimental Therapeutics, Graduate School of Medicine, Akita University, 1-1-1 Hondo, Akita, 010-8543, Japan.,Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institutes of Child Health and Human Development, National Institutes of Health, 35A Convent Drive, Bethesda, MD 20892-3752, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institutes of Child Health and Human Development, National Institutes of Health, 35A Convent Drive, Bethesda, MD 20892-3752, USA
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77
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Eno CC, Graakjaer J, Svaneby D, Nizon M, Kianmahd J, Signer R, Martinez-Agosto JA, Quintero-Rivera F. 14q32.11 microdeletion including CALM1, TTC7B, PSMC1, and RPS6KA5: A new potential cause of developmental and language delay in three unrelated patients. Am J Med Genet A 2021; 185:1519-1524. [PMID: 33634591 DOI: 10.1002/ajmg.a.62117] [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: 08/12/2020] [Revised: 12/14/2020] [Accepted: 01/23/2021] [Indexed: 12/18/2022]
Abstract
Three unrelated patients with similar microdeletions of chromosome 14q32.11 with shared phenotypes including language and developmental delay, and four overlapping genes -CALM1, TTC7B, PSMC1, and RPS6KA5 have been presented. All four genes are expressed in the brain and have haploinsufficiency scores, which reflect low tolerance to loss of function variation. An insight on the genes in the overlapping region, which may influence the resulting phenotype has been provided. Given the three patients' similar phenotypes and lack of normal variation in this region, it was suggested that this microdeletion may be associated with developmental and language delay.
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Affiliation(s)
- Celeste C Eno
- Department of Academic Pathology, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Jesper Graakjaer
- Department of Clinical Genetics, Lillebaelt Hospital, Vejle, Denmark
| | - Dea Svaneby
- Department of Clinical Genetics, Lillebaelt Hospital, Vejle, Denmark
| | - Mathilde Nizon
- Department of Medical Genetics, CHU Nantes, Nantes, France
| | - Jessica Kianmahd
- Departments of Human Genetics and Pediatrics, Division of Medical Genetics, UCLA, Los Angeles, California, USA
| | - Rebecca Signer
- Departments of Human Genetics and Pediatrics, Division of Medical Genetics, UCLA, Los Angeles, California, USA
| | - Julian A Martinez-Agosto
- Departments of Human Genetics and Pediatrics, Division of Medical Genetics, UCLA, Los Angeles, California, USA
| | - Fabiola Quintero-Rivera
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, California, USA
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78
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Plasma Membrane Phosphatidylinositol-4-Phosphate Is Not Necessary for Candida albicans Viability yet Is Key for Cell Wall Integrity and Systemic Infection. mBio 2021; 13:e0387321. [PMID: 35164565 PMCID: PMC8942462 DOI: 10.1128/mbio.03873-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Phosphatidylinositol phosphates are key phospholipids with a range of regulatory roles, including membrane trafficking and cell polarity. Phosphatidylinositol-4-phosphate [PI(4)P] at the Golgi apparatus is required for the budding-to-filamentous-growth transition in the human-pathogenic fungus Candida albicans; however, the role of plasma membrane PI(4)P is unclear. We have investigated the importance of this phospholipid in C. albicans growth, stress response, and virulence by generating mutant strains with decreased levels of plasma membrane PI(4)P, via deletion of components of the PI-4-kinase complex, i.e., Efr3, Ypp1, and Stt4. The amounts of plasma membrane PI(4)P in the efr3Δ/Δ and ypp1Δ/Δ mutants were ∼60% and ∼40%, respectively, of that in the wild-type strain, whereas it was nearly undetectable in the stt4Δ/Δ mutant. All three mutants had reduced plas7ma membrane phosphatidylserine (PS). Although these mutants had normal yeast-phase growth, they were defective in filamentous growth, exhibited defects in cell wall integrity, and had an increased exposure of cell wall β(1,3)-glucan, yet they induced a range of hyphal-specific genes. In a mouse model of hematogenously disseminated candidiasis, fungal plasma membrane PI(4)P levels directly correlated with virulence; the efr3Δ/Δ mutant had wild-type virulence, the ypp1Δ/Δ mutant had attenuated virulence, and the stt4Δ/Δ mutant caused no lethality. In the mouse model of oropharyngeal candidiasis, only the ypp1Δ/Δ mutant had reduced virulence, indicating that plasma membrane PI(4)P is less important for proliferation in the oropharynx. Collectively, these results demonstrate that plasma membrane PI(4)P levels play a central role in filamentation, cell wall integrity, and virulence in C. albicans. IMPORTANCE While the PI-4-kinases Pik1 and Stt4 both produce PI(4)P, the former generates PI(4)P at the Golgi apparatus and the latter at the plasma membrane, and these two pools are functionally distinct. To address the importance of plasma membrane PI(4)P in Candida albicans, we generated deletion mutants of the three putative plasma membrane PI-4-kinase complex components and quantified the levels of plasma membrane PI(4)P in each of these strains. Our work reveals that this phosphatidylinositol phosphate is specifically critical for the yeast-to-hyphal transition, cell wall integrity, and virulence in a mouse systemic infection model. The significance of this work is in identifying a plasma membrane phospholipid that has an infection-specific role, which is attributed to the loss of plasma membrane PI(4)P resulting in β(1,3)-glucan unmasking.
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79
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Wang Y, Yuan P, Grabon A, Tripathi A, Lee D, Rodriguez M, Lönnfors M, Eisenberg-Bord M, Wang Z, Man Lam S, Schuldiner M, Bankaitis VA. Noncanonical regulation of phosphatidylserine metabolism by a Sec14-like protein and a lipid kinase. J Cell Biol 2021; 219:151686. [PMID: 32303746 PMCID: PMC7199851 DOI: 10.1083/jcb.201907128] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 12/20/2019] [Accepted: 02/10/2020] [Indexed: 01/20/2023] Open
Abstract
The yeast phosphatidylserine (PtdSer) decarboxylase Psd2 is proposed to engage in a membrane contact site (MCS) for PtdSer decarboxylation to phosphatidylethanolamine (PtdEtn). This proposed MCS harbors Psd2, the Sec14-like phosphatidylinositol transfer protein (PITP) Sfh4, the Stt4 phosphatidylinositol (PtdIns) 4-OH kinase, the Scs2 tether, and an uncharacterized protein. We report that, of these components, only Sfh4 and Stt4 regulate Psd2 activity in vivo. They do so via distinct mechanisms. Sfh4 operates via a mechanism for which its PtdIns-transfer activity is dispensable but requires an Sfh4-Psd2 physical interaction. The other requires Stt4-mediated production of PtdIns-4-phosphate (PtdIns4P), where Stt4 (along with the Sac1 PtdIns4P phosphatase and endoplasmic reticulum–plasma membrane tethers) indirectly modulate Psd2 activity via a PtdIns4P homeostatic mechanism that influences PtdSer accessibility to Psd2. These results identify an example in which the biological function of a Sec14-like PITP is cleanly uncoupled from its canonical in vitro PtdIns-transfer activity and challenge popular functional assumptions regarding lipid-transfer protein involvements in MCS function.
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Affiliation(s)
- Yaxi Wang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX.,Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Peihua Yuan
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Aby Grabon
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Ashutosh Tripathi
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Dongju Lee
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Martin Rodriguez
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX
| | - Max Lönnfors
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | | | - Zehua Wang
- University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Vytas A Bankaitis
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX.,Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX.,Department of Chemistry, Texas A&M University, College Station, TX
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80
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Type 1 diabetes: genes associated with disease development. Cent Eur J Immunol 2021; 45:439-453. [PMID: 33658892 PMCID: PMC7882399 DOI: 10.5114/ceji.2020.103386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 01/02/2020] [Indexed: 11/17/2022] Open
Abstract
Type 1 diabetes (T1D) is the third most common autoimmune disease which develops due to genetic and environmental risk factors. Based on the World Health Organization (WHO) report from 2014 the number of people suffering from all types of diabetes ascended to 422 million, compared to 108 million in 1980. It was calculated that this number will double by the end of 2030. In 2015 American Diabetes Association (ADA) announced that 30.3 million Americans (that is 9.4% of the overall population) had diabetes of which only approximately 1.25 million had T1D. Nowadays, T1D represents roughly 10% of adult diabetes cases total. Multiple genetic abnormalities at different loci have been found to contribute to type 1 diabetes development. The analysis of genome-wide association studies (GWAS) of T1D has identified over 50 susceptible regions (and genes within these regions). Many of these regions are defined by single nucleotide polymorphisms (SNPs) but molecular mechanisms through which they increase or lower the risk of diabetes remain unknown. Genetic factors (in existence since birth) can be detected long before the emergence of immunological or clinical markers. Therefore, a comprehensive understanding of the multiple genetic factors underlying T1D is extremely important for further clinical trials and development of personalized medicine for diabetic patients. We present an overview of current studies and information about regions in the human genome associated with T1D. Moreover, we also put forward information about epigenetic modifications, non-coding RNAs and environmental factors involved in T1D development and onset.
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81
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Karalok ZS, Gurkasb E, Aydinc K, Ceylaner S. Hypomyelination and Congenital Cataract: Three Siblings Presentation. J Pediatr Neurosci 2021; 15:270-273. [PMID: 33531944 PMCID: PMC7847105 DOI: 10.4103/jpn.jpn_161_18] [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: 11/11/2018] [Revised: 11/18/2019] [Accepted: 05/24/2020] [Indexed: 11/25/2022] Open
Abstract
Hypomyelination and congenital cataract (HCC) is a condition, which is caused by mutations in the FAM126A gene and is characterized by congenital cataract, progressive neurologic impairment, and myelin deficiency in both the central and peripheral nervous system. We present the findings of three siblings who applied to us with the same clinical features. These patients were referred to our clinic due to the presence of bilateral congenital cataract and progressive neurological impairment with peripheral neuropathy. Brain magnetic resonance imaging (MRI) showed diffuse hypomyelination, whereas neurophysiological studies showed sensorimotor peripheral polyneuropathy. Cases with hypomyelination in MRI represent the largest group of undiagnosed diseases among patients with leukoencephalopathies. To diagnose cases with peripheral neuropathy, their clinical and neuroradiological findings must be identified. These findings can guide clinicians to appropriate molecular investigations.
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Affiliation(s)
- Zeynep Selen Karalok
- Department of Pediatric Neurology, Akdeniz University School of Medicine, Antalya, Turkey
| | - Esra Gurkasb
- Department of Pediatric Neurology, Ankara Children's Hospital Hematology-Oncology Research and Training Hospital, Ankara, Turkey
| | - Kursad Aydinc
- Department of Pediatric Neurology, Medipol University, İstanbul, Turkey
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82
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Balla T. Rushing to maintain plasma membrane phosphoinositide levels. J Gen Physiol 2020; 152:211537. [PMID: 33186443 PMCID: PMC7671492 DOI: 10.1085/jgp.202012793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
New findings by Myeong et al. provide further details on how cells maintain their plasma membrane PI(4,5)P2 levels when stimulated via M1 muscarinic receptors
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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83
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Lete MG, Tripathi A, Chandran V, Bankaitis VA, McDermott MI. Lipid transfer proteins and instructive regulation of lipid kinase activities: Implications for inositol lipid signaling and disease. Adv Biol Regul 2020; 78:100740. [PMID: 32992233 PMCID: PMC7986245 DOI: 10.1016/j.jbior.2020.100740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/16/2020] [Accepted: 06/24/2020] [Indexed: 05/17/2023]
Abstract
Cellular membranes are critical platforms for intracellular signaling that involve complex interfaces between lipids and proteins, and a web of interactions between a multitude of lipid metabolic pathways. Membrane lipids impart structural and functional information in this regulatory circuit that encompass biophysical parameters such as membrane thickness and fluidity, as well as chaperoning the interactions of protein binding partners. Phosphatidylinositol and its phosphorylated derivatives, the phosphoinositides, play key roles in intracellular membrane signaling, and these involvements are translated into an impressively diverse set of biological outcomes. The phosphatidylinositol transfer proteins (PITPs) are key regulators of phosphoinositide signaling. Found in a diverse array of organisms from plants, yeast and apicomplexan parasites to mammals, PITPs were initially proposed to be simple transporters of lipids between intracellular membranes. It now appears increasingly unlikely that the soluble versions of these proteins perform such functions within the cell. Rather, these serve to facilitate the activity of intrinsically biologically insufficient inositol lipid kinases and, in so doing, promote diversification of the biological outcomes of phosphoinositide signaling. The central engine for execution of such functions is the lipid exchange cycle that is a fundamental property of PITPs. How PITPs execute lipid exchange remains very poorly understood. Molecular dynamics simulation approaches are now providing the first atomistic insights into how PITPs, and potentially other lipid-exchange/transfer proteins, operate.
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Affiliation(s)
- Marta G Lete
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Institute Biofisika (UPV/EHU, CSIC) and University of the Basque Country, Leioa, Spain
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vijay Chandran
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77840, USA
| | - Mark I McDermott
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA.
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84
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Almeida C, Amaral MD. A central role of the endoplasmic reticulum in the cell emerges from its functional contact sites with multiple organelles. Cell Mol Life Sci 2020; 77:4729-4745. [PMID: 32313974 PMCID: PMC11104799 DOI: 10.1007/s00018-020-03523-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/30/2020] [Accepted: 04/06/2020] [Indexed: 02/08/2023]
Abstract
Early eukaryotic cells emerged from the compartmentalization of metabolic processes into specific organelles through the development of an endomembrane system (ES), a precursor of the endoplasmic reticulum (ER), which was essential for their survival. Recently, substantial evidence emerged on how organelles communicate among themselves and with the plasma membrane (PM) through contact sites (CSs). From these studies, the ER-the largest single structure in eukaryotic cells-emerges as a central player communicating with all organelles to coordinate cell functions and respond to external stimuli to maintain cellular homeostasis. Herein we review the functional insights into the ER-CSs with other organelles in a physiological perspective. We hypothesize that, in addition to the primitive role by the ES in the appearance of proto-eukaryotes, its successor-the ER-emerges as the key coordinator of inter-organelle/PM communication. The ER thus appears to be the 'maestro' driving eukaryotic cell evolution by incorporating new functions/organelles, while remaining the real coordinator overarching cellular functions and orchestrating them with the external milieu.
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Affiliation(s)
- Celso Almeida
- Faculty of Sciences, BioISI, Biosystems and Integrative Sciences Institute, University of Lisboa, Campo Grande, C8 bdg, 1749-016, Lisbon, Portugal.
| | - Margarida D Amaral
- Faculty of Sciences, BioISI, Biosystems and Integrative Sciences Institute, University of Lisboa, Campo Grande, C8 bdg, 1749-016, Lisbon, Portugal.
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85
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Pemberton JG, Kim YJ, Humpolickova J, Eisenreichova A, Sengupta N, Toth DJ, Boura E, Balla T. Defining the subcellular distribution and metabolic channeling of phosphatidylinositol. J Cell Biol 2020; 219:133809. [PMID: 32211894 PMCID: PMC7054996 DOI: 10.1083/jcb.201906130] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 11/08/2019] [Accepted: 12/23/2019] [Indexed: 02/06/2023] Open
Abstract
Phosphatidylinositol (PI) is an essential structural component of eukaryotic membranes that also serves as the common precursor for polyphosphoinositide (PPIn) lipids. Despite the recognized importance of PPIn species for signal transduction and membrane homeostasis, there is still a limited understanding of the relationship between PI availability and the turnover of subcellular PPIn pools. To address these shortcomings, we established a molecular toolbox for investigations of PI distribution within intact cells by exploiting the properties of a bacterial enzyme, PI-specific PLC (PI-PLC). Using these tools, we find a minor presence of PI in membranes of the ER, as well as a general enrichment within the cytosolic leaflets of the Golgi complex, peroxisomes, and outer mitochondrial membrane, but only detect very low steady-state levels of PI within the plasma membrane (PM) and endosomes. Kinetic studies also demonstrate the requirement for sustained PI supply from the ER for the maintenance of monophosphorylated PPIn species within the PM, Golgi complex, and endosomal compartments.
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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, National Institutes of Health, Bethesda, MD
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Jana Humpolickova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Andrea Eisenreichova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Nivedita Sengupta
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Daniel J Toth
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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86
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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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87
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Katan M, Cockcroft S. Phosphatidylinositol(4,5)bisphosphate: diverse functions at the plasma membrane. Essays Biochem 2020; 64:513-531. [PMID: 32844214 PMCID: PMC7517351 DOI: 10.1042/ebc20200041] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 07/25/2020] [Accepted: 07/29/2020] [Indexed: 12/20/2022]
Abstract
Phosphatidylinositol(4,5) bisphosphate (PI(4,5)P2) has become a major focus in biochemistry, cell biology and physiology owing to its diverse functions at the plasma membrane. As a result, the functions of PI(4,5)P2 can be explored in two separate and distinct roles - as a substrate for phospholipase C (PLC) and phosphoinositide 3-kinase (PI3K) and as a primary messenger, each having unique properties. Thus PI(4,5)P2 makes contributions in both signal transduction and cellular processes including actin cytoskeleton dynamics, membrane dynamics and ion channel regulation. Signalling through plasma membrane G-protein coupled receptors (GPCRs), receptor tyrosine kinases (RTKs) and immune receptors all use PI(4,5)P2 as a substrate to make second messengers. Activation of PI3K generates PI(3,4,5)P3 (phosphatidylinositol(3,4,5)trisphosphate), a lipid that recruits a plethora of proteins with pleckstrin homology (PH) domains to the plasma membrane to regulate multiple aspects of cellular function. In contrast, PLC activation results in the hydrolysis of PI(4,5)P2 to generate the second messengers, diacylglycerol (DAG), an activator of protein kinase C and inositol(1,4,5)trisphosphate (IP3/I(1,4,5)P3) which facilitates an increase in intracellular Ca2+. Decreases in PI(4,5)P2 by PLC also impact on functions that are dependent on the intact lipid and therefore endocytosis, actin dynamics and ion channel regulation are subject to control. Spatial organisation of PI(4,5)P2 in nanodomains at the membrane allows for these multiple processes to occur concurrently.
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Affiliation(s)
- Matilda Katan
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, U.K
| | - Shamshad Cockcroft
- Department of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, 21 University Street, London WC1E 6JJ, U.K
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88
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Balla T, Gulyas G, Kim YJ, Pemberton J. PHOSPHOINOSITIDES AND CALCIUM SIGNALING. A MARRIAGE ARRANGED IN ER-PM CONTACT SITES. CURRENT OPINION IN PHYSIOLOGY 2020; 17:149-157. [PMID: 32944676 DOI: 10.1016/j.cophys.2020.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Calcium (Ca2+) ions are critically important in orchestrating countless regulatory processes in eukaryotic cells. Consequently, cells tightly control cytoplasmic Ca2+ concentrations using a complex array of Ca2+-selective ion channels, transporters, and signaling effectors. Ca2+ transport through various cellular membranes is highly dependent on the intrinsic properties of specific membrane compartments and conversely, local Ca2+ changes have profound effects on the membrane lipid composition of such membrane sub-domains. In particular, inositol phospholipids are a minor class of phospholipids that play pivotal roles in the control of Ca2+-dependent signaling pathways. In this review, we will highlight some of the recent advances in this field as well as their impact in defining future research directions.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Gergo Gulyas
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Joshua Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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89
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Kattan WE, Hancock JF. RAS Function in cancer cells: translating membrane biology and biochemistry into new therapeutics. Biochem J 2020; 477:2893-2919. [PMID: 32797215 PMCID: PMC7891675 DOI: 10.1042/bcj20190839] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 02/07/2023]
Abstract
The three human RAS proteins are mutated and constitutively activated in ∼20% of cancers leading to cell growth and proliferation. For the past three decades, many attempts have been made to inhibit these proteins with little success. Recently; however, multiple methods have emerged to inhibit KRAS, the most prevalently mutated isoform. These methods and the underlying biology will be discussed in this review with a special focus on KRAS-plasma membrane interactions.
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Affiliation(s)
- Walaa E. Kattan
- Department of Integrative Biology and Pharmacology, McGovern Medical School University of Texas Health Science Center at Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, TX 77030, USA
| | - John F. Hancock
- Department of Integrative Biology and Pharmacology, McGovern Medical School University of Texas Health Science Center at Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, TX 77030, USA
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90
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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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91
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Basu U, Balakrishnan SS, Janardan V, Raghu P. A PI4KIIIα protein complex is required for cell viability during Drosophila wing development. Dev Biol 2020; 462:208-222. [PMID: 32194035 DOI: 10.1016/j.ydbio.2020.03.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/06/2020] [Accepted: 03/07/2020] [Indexed: 01/02/2023]
Abstract
Phosphatidylinositol 4 phosphate (PI4P) and phosphatidylinositol 4,5 bisphosphate [PI(4,5)P2] are enriched on the inner leaflet of the plasma membrane and proposed to be key determinants of its function. PI4P is also the biochemical precursor for the synthesis of PI(4,5)P2 but can itself also bind to and regulate protein function. However, the independent function of PI4P at the plasma membrane in supporting cell function in metazoans during development in vivo remains unclear. We find that conserved components of a multi-protein complex composed of phosphatidylinositol 4-kinase IIIα (PI4KIIIα), TTC7 and Efr3 is required for normal vein patterning and wing development. Depletion of each of these three components of the PI4KIIIα complex in developing wing cells results in altered wing morphology. These effects are associated with an increase in apoptosis and can be rescued by expression of an inhibitor of Drosophila caspase. We find that in contrast to previous reports, PI4KIIIα depletion does not alter key outputs of hedgehog signalling in developing wing discs. Depletion of PI4KIIIα results in reduced PI4P levels at the plasma membrane of developing wing disc cells while levels of PI(4,5)P2, the downstream metabolite of PI4P, are not altered. Thus, PI4P itself generated by the activity of the PI4KIIIα complex plays an essential role in supporting cell viability in the developing Drosophila wing disc.
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Affiliation(s)
- Urbashi Basu
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore, 560065, India
| | - Sruthi S Balakrishnan
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore, 560065, India
| | - Vishnu Janardan
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore, 560065, India
| | - Padinjat Raghu
- National Centre for Biological Sciences-TIFR, GKVK Campus, Bellary Road, Bangalore, 560065, India.
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92
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Griffiths NW, Del Bel LM, Wilk R, Brill JA. Cellular homeostasis in the Drosophila retina requires the lipid phosphatase Sac1. Mol Biol Cell 2020; 31:1183-1199. [PMID: 32186963 PMCID: PMC7353163 DOI: 10.1091/mbc.e20-02-0161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The complex functions of cellular membranes, and thus overall cell physiology, depend on the distribution of crucial lipid species. Sac1 is an essential, conserved, ER-localized phosphatase whose substrate, phosphatidylinositol 4-phosphate (PI4P), coordinates secretory trafficking and plasma membrane function. PI4P from multiple pools is delivered to Sac1 by oxysterol-binding protein and related proteins in exchange for other lipids and sterols, which places Sac1 at the intersection of multiple lipid distribution pathways. However, much remains unknown about the roles of Sac1 in subcellular homeostasis and organismal development. Using a temperature-sensitive allele (Sac1ts), we show that Sac1 is required for structural integrity of the Drosophila retinal floor. The βps-integrin Myospheroid, which is necessary for basal cell adhesion, is mislocalized in Sac1ts retinas. In addition, the adhesion proteins Roughest and Kirre, which coordinate apical retinal cell patterning at an earlier stage, accumulate within Sac1ts retinal cells due to impaired endo-lysosomal degradation. Moreover, Sac1 is required for ER homeostasis in Drosophila retinal cells. Together, our data illustrate the importance of Sac1 in regulating multiple aspects of cellular homeostasis during tissue development.
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Affiliation(s)
- Nigel W Griffiths
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Lauren M Del Bel
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Ronit Wilk
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Julie A Brill
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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93
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Nakamura A, Oki C, Kato K, Fujinuma S, Maryu G, Kuwata K, Yoshii T, Matsuda M, Aoki K, Tsukiji S. Engineering Orthogonal, Plasma Membrane-Specific SLIPT Systems for Multiplexed Chemical Control of Signaling Pathways in Living Single Cells. ACS Chem Biol 2020; 15:1004-1015. [PMID: 32162909 DOI: 10.1021/acschembio.0c00024] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Most cell behaviors are the outcome of processing information from multiple signals generated upon cell stimulation. Thus, a systematic understanding of cellular systems requires methods that allow the activation of more than one specific signaling molecule or pathway within a cell. However, the construction of tools suitable for such multiplexed signal control remains challenging. In this work, we aimed to develop a platform for chemically manipulating multiple signaling molecules/pathways in living mammalian cells based on self-localizing ligand-induced protein translocation (SLIPT). SLIPT is an emerging chemogenetic tool that controls protein localization and cell signaling using synthetic self-localizing ligands (SLs). Focusing on the inner leaflet of the plasma membrane (PM), where there is a hub of intracellular signaling networks, here we present the design and engineering of two new PM-specific SLIPT systems based on an orthogonal eDHFR and SNAP-tag pair. These systems rapidly induce translocation of eDHFR- and SNAP-tag-fusion proteins from the cytoplasm to the PM specifically in a time scale of minutes upon addition of the corresponding SL. We then show that the combined use of the two systems enables chemically inducible, individual translocation of two distinct proteins in the same cell. Finally, by integrating the orthogonal SLIPT systems with fluorescent reporters, we demonstrate simultaneous multiplexed activation and fluorescence imaging of endogenous ERK and Akt activities in a single cell. Collectively, orthogonal PM-specific SLIPT systems provide a powerful new platform for multiplexed chemical signal control in living single cells, offering new opportunities for dissecting cell signaling networks and synthetic cell manipulation.
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Affiliation(s)
- Akinobu Nakamura
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Choji Oki
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Kenya Kato
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Satoko Fujinuma
- Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188, Japan
| | - Gembu Maryu
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
- National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Keiko Kuwata
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - Tatsuyuki Yoshii
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
- PRESTO, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Michiyuki Matsuda
- Laboratory of Bioimaging and Cell Signaling, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhiro Aoki
- National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
- Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
- Department of Basic Biology, Faculty of Life Science, SOKENDAI, The Graduate University for Advanced Studies, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Shinya Tsukiji
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
- Frontier Research Institute for Materials Science (FRIMS), Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
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94
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Gulyás G, Sohn M, Kim YJ, Várnai P, Balla T. ORP3 phosphorylation regulates phosphatidylinositol 4-phosphate and Ca 2+ dynamics at plasma membrane-ER contact sites. J Cell Sci 2020; 133:jcs.237388. [PMID: 32041906 DOI: 10.1242/jcs.237388] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 01/29/2020] [Indexed: 12/20/2022] Open
Abstract
Oxysterol-binding protein (OSBP)-related proteins (ORPs) mediate non-vesicular lipid transfer between intracellular membranes. Phosphoinositide (PI) gradients play important roles in the ability of OSBP and some ORPs to transfer cholesterol and phosphatidylserine between the endoplasmic reticulum (ER) and other organelle membranes. Here, we show that plasma membrane (PM) association of ORP3 (also known as OSBPL3), a poorly characterized ORP family member, is triggered by protein kinase C (PKC) activation, especially when combined with Ca2+ increases, and is determined by both PI(4,5)P 2 and PI4P After activation, ORP3 efficiently extracts PI4P and to a lesser extent phosphatidic acid from the PM, and slightly increases PM cholesterol levels. Full activation of ORP3 resulted in decreased PM PI4P levels and inhibited Ca2+ entry via the store-operated Ca2+ entry pathway. The C-terminal region of ORP3 that follows the strictly defined lipid transfer domain was found to be critical for the proper localization and function of the protein.
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Affiliation(s)
- Gergő Gulyás
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.,Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Mira Sohn
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Péter Várnai
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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95
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Omnus DJ, Cadou A, Thomas FB, Bader JM, Soh N, Chung GHC, Vaughan AN, Stefan CJ. A heat-sensitive Osh protein controls PI4P polarity. BMC Biol 2020; 18:28. [PMID: 32169085 PMCID: PMC7071650 DOI: 10.1186/s12915-020-0758-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 02/26/2020] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Phosphoinositide lipids provide spatial landmarks during polarized cell growth and migration. Yet how phosphoinositide gradients are oriented in response to extracellular cues and environmental conditions is not well understood. Here, we elucidate an unexpected mode of phosphatidylinositol 4-phosphate (PI4P) regulation in the control of polarized secretion. RESULTS We show that PI4P is highly enriched at the plasma membrane of growing daughter cells in budding yeast where polarized secretion occurs. However, upon heat stress conditions that redirect secretory traffic, PI4P rapidly increases at the plasma membrane in mother cells resulting in a more uniform PI4P distribution. Precise control of PI4P distribution is mediated through the Osh (oxysterol-binding protein homology) proteins that bind and present PI4P to a phosphoinositide phosphatase. Interestingly, Osh3 undergoes a phase transition upon heat stress conditions, resulting in intracellular aggregates and reduced cortical localization. Both the Osh3 GOLD and ORD domains are sufficient to form heat stress-induced aggregates, indicating that Osh3 is highly tuned to heat stress conditions. Upon loss of Osh3 function, the polarized distribution of both PI4P and the exocyst component Exo70 are impaired. Thus, an intrinsically heat stress-sensitive PI4P regulatory protein controls the spatial distribution of phosphoinositide lipid metabolism to direct secretory trafficking as needed. CONCLUSIONS Our results suggest that control of PI4P metabolism by Osh proteins is a key determinant in the control of polarized growth and secretion.
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Affiliation(s)
- Deike J Omnus
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
- Present address: Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Angela Cadou
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Ffion B Thomas
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Jakob M Bader
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
- Present address: Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Nathaniel Soh
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Gary H C Chung
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Andrew N Vaughan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - Christopher J Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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96
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Xu C, Wan Z, Shaheen S, Wang J, Yang Z, Liu W. A PI(4,5)P2-derived "gasoline engine model" for the sustained B cell receptor activation. Immunol Rev 2020; 291:75-90. [PMID: 31402506 DOI: 10.1111/imr.12775] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/08/2019] [Accepted: 05/09/2019] [Indexed: 12/14/2022]
Abstract
To efficiently initiate activation responses against rare ligands in the microenvironment, lymphocytes employ sophisticated mechanisms involving signaling amplification. Recently, a signaling amplification mechanism initiated from phosphatidylinositol (PI) 4, 5-biphosphate [PI(4,5)P2] hydrolysis and synthesis for sustained B cell activation has been reported. Antigen and B cell receptor (BCR) recognition triggered the prompt reduction of PI(4,5)P2 density within the BCR microclusters, which led to the positive feedback for the synthesis of PI(4,5)P2 outside of the BCR microclusters. At single molecule level, the diffusion of PI(4,5)P2 was slow, allowing for the maintenance of a PI(4,5)P2 density gradient between the inside and outside of the BCR microclusters and the persistent supply of PI(4,5)P2 from outside to inside of the BCR microclusters. Here, we review studies that have contributed to uncovering the molecular mechanisms of PI(4,5)P2-derived signaling amplification model. Based on these studies, we proposed a "gasoline engine model" in which the activation of B cell signaling inside the microclusters is similar to the working principle of burning gasoline within the engine chamber of a gasoline engine. We also discuss the evidences showing the potential universality of this model and future prospects.
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Affiliation(s)
- Chenguang Xu
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Zhengpeng Wan
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Samina Shaheen
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Jing Wang
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
| | - Zhiyong Yang
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
| | - Wanli Liu
- Center for Life Sciences, MOE Key Laboratory of Protein Sciences, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing Key Lab for Immunological Research on Chronic Diseases, School of Life Sciences, Institute for Immunology, Tsinghua University, Beijing, China
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97
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Ren C, Yuan Q, Jian X, Randazzo PA, Tang W, Wu D. Small GTPase ARF6 Is a Coincidence-Detection Code for RPH3A Polarization in Neutrophil Polarization. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2020; 204:1012-1021. [PMID: 31924649 PMCID: PMC6994837 DOI: 10.4049/jimmunol.1901080] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/10/2019] [Indexed: 12/21/2022]
Abstract
Cell polarization is a key step for leukocytes adhesion and transmigration during leukocytes' inflammatory infiltration. Polarized localization of plasma membrane (PM) phosphatidylinositol-4-phosphate (PtdIns4P) directs the polarization of RPH3A, which contains a PtdIns4P binding site. Consequently, RPH3A mediates the RAB21 and PIP5K1C90 polarization, which is important for neutrophil adhesion to endothelia during inflammation. However, the mechanism by which RPH3A is recruited only to PM PtdIns4P rather than Golgi PtdIns4P remains unclear. By using ADP-ribosylation factor 6 (ARF6) small interfering RNA, ARF6 dominant-negative mutant ARF6(T27N), and ARF6 activation inhibitor SecinH3, we demonstrate that ARF6 plays an important role in the polarization of RPH3A, RAB21, and PIP5K1C90 in murine neutrophils. PM ARF6 is polarized and colocalized with RPH3A, RAB21, PIP5K1C90, and PM PtdIns4P in mouse and human neutrophils upon integrin stimulation. Additionally, ARF6 binds to RPH3A and enhances the interaction between the PM PtdIns4P and RPH3A. Consistent with functional roles of polarization of RPH3A, Rab21, and PIP5K1C90, ARF6 is also required for neutrophil adhesion on the inflamed endothelial layer. Our study reveals a previously unknown role of ARF6 in neutrophil polarization as being the coincidence-detection code with PM PtdIns4P. Cooperation of ARF6 and PM PtdIns4P direct RPH3A polarization, which is important for neutrophil firm adhesion to endothelia.
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Affiliation(s)
- Chunguang Ren
- Department of Pharmacology, Vascular Biology and Therapeutic Program, School of Medicine, Yale University, New Haven, CT 06520; and
| | - Qianying Yuan
- Department of Pharmacology, Vascular Biology and Therapeutic Program, School of Medicine, Yale University, New Haven, CT 06520; and
| | - Xiaoying Jian
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Wenwen Tang
- Department of Pharmacology, Vascular Biology and Therapeutic Program, School of Medicine, Yale University, New Haven, CT 06520; and
| | - Dianqing Wu
- Department of Pharmacology, Vascular Biology and Therapeutic Program, School of Medicine, Yale University, New Haven, CT 06520; and
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98
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de la Cruz L, Traynor-Kaplan A, Vivas O, Hille B, Jensen JB. Plasma membrane processes are differentially regulated by type I phosphatidylinositol phosphate 5-kinases and RASSF4. J Cell Sci 2020; 133:jcs.233254. [PMID: 31831523 DOI: 10.1242/jcs.233254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 12/06/2019] [Indexed: 12/11/2022] Open
Abstract
Phosphoinositide lipids regulate many cellular processes and are synthesized by lipid kinases. Type I phosphatidylinositol phosphate 5-kinases (PIP5KIs) generate phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P 2]. Several phosphoinositide-sensitive readouts revealed the nonequivalence of overexpressing PIP5KIβ, PIP5KIγ or Ras association domain family 4 (RASSF4), believed to activate PIP5KIs. Mass spectrometry showed that each of these three proteins increased total cellular phosphatidylinositol bisphosphates (PtdInsP 2) and trisphosphates (PtdInsP 3) at the expense of phosphatidylinositol phosphate (PtdInsP) without changing lipid acyl chains. Analysis of KCNQ2/3 channels and PH domains confirmed an increase in plasma membrane PtdIns(4,5)P 2 in response to PIP5KIβ or PIP5KIγ overexpression, but RASSF4 required coexpression with PIP5KIγ to increase plasma membrane PtdIns(4,5)P 2 Effects on the several steps of store-operated calcium entry (SOCE) were not explained by plasma membrane phosphoinositide increases alone. PIP5KIβ and RASSF4 increased STIM1 proximity to the plasma membrane, accelerated STIM1 mobilization and speeded onset of SOCE; however, PIP5KIγ reduced STIM1 recruitment but did not change induced Ca2+ entry. These differences imply actions through different segregated pools of phosphoinositides and specific protein-protein interactions and targeting.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Lizbeth de la Cruz
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, USA
| | - Alexis Traynor-Kaplan
- ATK Innovation, Analytics and Discovery, North Bend, WA 98045, USA.,Department of Medicine/Gastroenterology, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Oscar Vivas
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, USA
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, USA
| | - Jill B Jensen
- Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle, WA 98195-7290, USA
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99
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Forsyth JK, Nachun D, Gandal MJ, Geschwind DH, Anderson AE, Coppola G, Bearden CE. Synaptic and Gene Regulatory Mechanisms in Schizophrenia, Autism, and 22q11.2 Copy Number Variant-Mediated Risk for Neuropsychiatric Disorders. Biol Psychiatry 2020; 87:150-163. [PMID: 31500805 PMCID: PMC6925326 DOI: 10.1016/j.biopsych.2019.06.029] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/10/2019] [Accepted: 06/27/2019] [Indexed: 01/28/2023]
Abstract
BACKGROUND 22q11.2 copy number variants are among the most highly penetrant genetic risk variants for developmental neuropsychiatric disorders such as schizophrenia (SCZ) and autism spectrum disorder (ASD). However, the specific mechanisms through which they confer risk remain unclear. METHODS Using a functional genomics approach, we integrated transcriptomic data from the developing human brain, genome-wide association findings for SCZ and ASD, protein interaction data, and gene expression signatures from SCZ and ASD postmortem cortex to 1) organize genes into the developmental cellular and molecular systems within which they operate, 2) identify neurodevelopmental processes associated with polygenic risk for SCZ and ASD across the allelic frequency spectrum, and 3) elucidate pathways and individual genes through which 22q11.2 copy number variants may confer risk for each disorder. RESULTS Polygenic risk for SCZ and ASD converged on partially overlapping neurodevelopmental modules involved in synaptic function and transcriptional regulation, with ASD risk variants additionally enriched for modules involved in neuronal differentiation during fetal development. The 22q11.2 locus formed a large protein network during development that disproportionately affected SCZ-associated and ASD-associated neurodevelopmental modules, including loading highly onto synaptic and gene regulatory pathways. SEPT5, PI4KA, and SNAP29 genes are candidate drivers of 22q11.2 synaptic pathology relevant to SCZ and ASD, and DGCR8 and HIRA are candidate drivers of disease-relevant alterations in gene regulation. CONCLUSIONS This approach offers a powerful framework to identify neurodevelopmental processes affected by diverse risk variants for SCZ and ASD and elucidate mechanisms through which highly penetrant, multigene copy number variants contribute to disease risk.
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Affiliation(s)
- Jennifer K Forsyth
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California.
| | - Daniel Nachun
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California
| | - Michael J Gandal
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California; Brain Research Institute, University of California, Los Angeles, Los Angeles, California
| | - Daniel H Geschwind
- Department of Human Genetics, University of California, Los Angeles, Los Angeles, California; Department of Neurology, University of California, Los Angeles, Los Angeles, California; Brain Research Institute, University of California, Los Angeles, Los Angeles, California
| | - Ariana E Anderson
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California
| | - Giovanni Coppola
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California; Department of Neurology, University of California, Los Angeles, Los Angeles, California; Brain Research Institute, University of California, Los Angeles, Los Angeles, California
| | - Carrie E Bearden
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California; Department of Psychology, University of California, Los Angeles, Los Angeles, California; Brain Research Institute, University of California, Los Angeles, Los Angeles, California.
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100
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A Genetic Screen in Drosophila To Identify Novel Regulation of Cell Growth by Phosphoinositide Signaling. G3-GENES GENOMES GENETICS 2020; 10:57-67. [PMID: 31704710 PMCID: PMC6945015 DOI: 10.1534/g3.119.400851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Phosphoinositides are lipid signaling molecules that regulate several conserved sub-cellular processes in eukaryotes, including cell growth. Phosphoinositides are generated by the enzymatic activity of highly specific lipid kinases and phosphatases. For example, the lipid PIP3, the Class I PI3 kinase that generates it and the phosphatase PTEN that metabolizes it are all established regulators of growth control in metazoans. To identify additional functions for phosphoinositides in growth control, we performed a genetic screen to identify proteins which when depleted result in altered tissue growth. By using RNA-interference mediated depletion coupled with mosaic analysis in developing eyes, we identified and classified additional candidates in the developing Drosophila melanogaster eye that regulate growth either cell autonomously or via cell-cell interactions. We report three genes: Pi3K68D, Vps34 and fwd that are important for growth regulation and suggest that these are likely to act via cell-cell interactions in the developing eye. Our findings define new avenues for the understanding of growth regulation in metazoan tissue development by phosphoinositide metabolizing proteins.
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