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Garcia-Rodas R, Labbaoui H, Orange F, Solis N, Zaragoza O, Filler SG, Bassilana M, Arkowitz RA. 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 DOI: 10.1128/mbio.03873-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [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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Low H, Mukhamedova N, Capettini LDSA, Xia Y, Carmichael I, Cody SH, Huynh K, Ditiatkovski M, Ohkawa R, Bukrinsky M, Meikle PJ, Choi SH, Field S, Miller YI, Sviridov D. Cholesterol Efflux-Independent Modification of Lipid Rafts by AIBP (Apolipoprotein A-I Binding Protein). Arterioscler Thromb Vasc Biol 2020; 40:2346-2359. [PMID: 32787522 PMCID: PMC7530101 DOI: 10.1161/atvbaha.120.315037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE AIBP (apolipoprotein A-I binding protein) is an effective and selective regulator of lipid rafts modulating many metabolic pathways originating from the rafts, including inflammation. The mechanism of action was suggested to involve stimulation by AIBP of cholesterol efflux, depleting rafts of cholesterol, which is essential for lipid raft integrity. Here we describe a different mechanism contributing to the regulation of lipid rafts by AIBP. Approach and Results: We demonstrate that modulation of rafts by AIBP may not exclusively depend on the rate of cholesterol efflux or presence of the key regulator of the efflux, ABCA1 (ATP-binding cassette transporter A-I). AIBP interacted with phosphatidylinositol 3-phosphate, which was associated with increased abundance and activation of Cdc42 and rearrangement of the actin cytoskeleton. Cytoskeleton rearrangement was accompanied with reduction of the abundance of lipid rafts, without significant changes in the lipid composition of the rafts. The interaction of AIBP with phosphatidylinositol 3-phosphate was blocked by AIBP substrate, NADPH (nicotinamide adenine dinucleotide phosphate), and both NADPH and silencing of Cdc42 interfered with the ability of AIBP to regulate lipid rafts and cholesterol efflux. CONCLUSIONS Our findings indicate that an underlying mechanism of regulation of lipid rafts by AIBP involves PIP-dependent rearrangement of the cytoskeleton.
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Affiliation(s)
- Hann Low
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Nigora Mukhamedova
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Luciano Dos Santos Aggum Capettini
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.).,Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil (L.d.S.A.C.)
| | - Yining Xia
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.)
| | - Irena Carmichael
- Department of Monash Micro Imaging, Monash University, Melbourne, VIC, Australia (I.C., S.H.C.)
| | - Stephen H Cody
- Department of Monash Micro Imaging, Monash University, Melbourne, VIC, Australia (I.C., S.H.C.)
| | - Kevin Huynh
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Michael Ditiatkovski
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Ryunosuke Ohkawa
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.).,Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Japan (R.O.)
| | - Michael Bukrinsky
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University School of Medicine and Health Sciences, DC (M.B.)
| | - Peter J Meikle
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.)
| | - Soo-Ho Choi
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.)
| | - Seth Field
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.)
| | - Yury I Miller
- Department of Medicine, University of California San Diego, La Jolla (L.d.S.A.C., Y.X., S.-H.C., S.F., Y.I.M.)
| | - Dmitri Sviridov
- Baker Heart and Diabetes Institute, Melbourne, VIC, Australia (H.L., N.M., K.H., M.D., R.O., P.J.M., D.S.).,Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia (D.S.)
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Tindall CA, Dommel S, Riedl V, Ulbricht D, Hanke S, Sträter N, Heiker JT. Membrane Phospholipids and Polyphosphates as Cofactors and Binding Molecules of SERPINA12 (vaspin). Molecules 2020; 25:E1992. [PMID: 32344508 DOI: 10.3390/molecules25081992] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 04/15/2020] [Accepted: 04/22/2020] [Indexed: 01/21/2023] Open
Abstract
Visceral adipose tissue derived serine protease inhibitor (vaspin) is a member of the serpin family and has been shown to have beneficial effects on glucose tolerance, insulin stability as well as adipose tissue inflammation, parameters seriously affected by obesity. Some of these effects require inhibition of target proteases such as kallikrein 7(KLK7) and many studies have demonstrated vaspin-mediated activation of intracellular signaling cascades in various cells and tissues. So far, little is known about the exact mechanism how vaspin may trigger these intracellular signaling events. In this study, we investigated and characterized the interaction of vaspin with membrane lipids and polyphosphates as well as their potential regulatory effects on serpin activity using recombinant vaspin and KLK7 proteins and functional protein variants thereof. Here, we show for the first time that vaspin binds to phospholipids and polyphosphates with varying effects on KLK7 inhibition. Vaspin binds strongly to monophosphorylated phosphatidylinositol phosphates (PtdInsP) with no effect on vaspin activation. Microscale thermophoresis (MST) measurements revealed high-affinity binding to polyphosphate 45 (KD: 466 ± 75 nM) and activation of vaspin in a heparin-like manner. Furthermore, we identified additional residues in the heparin binding site in β-sheet A by mutating five basic residues resulting in complete loss of high-affinity heparin binding. Finally, using lipid overlay assays, we show that these residues are additionally involved in PtdInsP binding. Phospholipids play a major role in membrane trafficking and signaling whereas polyphosphates are procoagulant and proinflammatory agents. The identification of phospholipids and polyphosphates as binding partners of vaspin will contribute to the understanding of vaspins involvement in membrane trafficking, signaling and beneficial effects associated with obesity.
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Chavent M, Karia D, Kalli AC, Domański J, Duncan AL, Hedger G, Stansfeld PJ, Seiradake E, Jones EY, Sansom MSP. Interactions of the EphA2 Kinase Domain with PIPs in Membranes: Implications for Receptor Function. Structure 2018; 26:1025-1034.e2. [PMID: 29887500 PMCID: PMC6039763 DOI: 10.1016/j.str.2018.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/15/2018] [Accepted: 05/08/2018] [Indexed: 11/29/2022]
Abstract
EphA2 is a member of the receptor tyrosine kinase family. Interactions of the cytoplasmic region of EphA2 with the cell membrane are functionally important and yet remain incompletely characterized. Molecular dynamics simulations combined with biochemical studies reveal the interactions of the transmembrane, juxtamembrane (JM), and kinase domains with the membrane. We describe how the kinase domain is oriented relative to the membrane and how the JM region can modulate this interaction. We highlight the role of phosphatidylinositol phosphates (PIPs) in mediating the interaction of the kinase domain with the membrane and, conversely, how positively charged patches at the kinase surface and in the JM region induce the formation of nanoclusters of PIP molecules in the membrane. Integration of these results with those from previous studies enable computational reconstitution of a near complete EphA2 receptor within a membrane, suggesting a role for receptor-lipid interactions in modulation of EphA2.
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Affiliation(s)
- Matthieu Chavent
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; Institut de Pharmacologie et de Biologie Structurale IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Dimple Karia
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Antreas C Kalli
- Leeds Institute of Cancer and Pathology, St James's University Hospital, University of Leeds, Leeds, UK
| | - Jan Domański
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Anna L Duncan
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - George Hedger
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Elena Seiradake
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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Ali I, Eu S, Koch D, Bleimling N, Goody RS, Müller MP. Structure of the tandem PX-PH domains of Bem3 from Saccharomyces cerevisiae. Acta Crystallogr F Struct Biol Commun 2018; 74:315-321. [PMID: 29718000 PMCID: PMC5931145 DOI: 10.1107/s2053230x18005915] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 04/16/2018] [Indexed: 11/11/2022] Open
Abstract
The structure of the tandem lipid-binding PX and pleckstrin-homology (PH) domains of the Cdc42 GTPase-activating protein Bem3 from Saccharomyces cerevisiae (strain S288c) has been determined to a resolution of 2.2 Å (Rwork = 21.1%, Rfree = 23.4%). It shows that the domains adopt a relative orientation that enables them to simultaneously bind to a membrane and suggests possible cooperativity in membrane binding.
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Affiliation(s)
- Imtiaz Ali
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Sungmin Eu
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Daniel Koch
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Nathalie Bleimling
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Roger S. Goody
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
| | - Matthias P. Müller
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany
- Faculty of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
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