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Nolle F, Starke LJ, Griffo A, Lienemann M, Jacobs K, Seemann R, Fleury JB, Hub JS, Hähl H. Hydrophobin Bilayer as Water Impermeable Protein Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:13790-13800. [PMID: 37726241 PMCID: PMC10552762 DOI: 10.1021/acs.langmuir.3c01006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/24/2023] [Indexed: 09/21/2023]
Abstract
One of the most important properties of membranes is their permeability to water and other small molecules. A targeted change in permeability allows the passage of molecules to be controlled. Vesicles made of membranes with low water permeability are preferable for drug delivery, for example, because they are more stable and maintain the drug concentration inside. This study reports on the very low water permeability of pure protein membranes composed of a bilayer of the amphiphilic protein hydrophobin HFBI. Using a droplet interface bilayer setup, we demonstrate that HFBI bilayers are essentially impermeable to water. HFBI bilayers withstand far larger osmotic pressures than lipid membranes. Only by disturbing the packing of the proteins in the HFBI bilayer is a measurable water permeability induced. To investigate possible molecular mechanisms causing the near-zero permeability, we used all-atom molecular dynamics simulations of various HFBI bilayer models. The simulations suggest that the experimental HFBI bilayer permeability is compatible neither with a lateral honeycomb structure, as found for HFBI monolayers, nor with a residual oil layer within the bilayer or with a disordered lateral packing similar to the packing in lipid bilayers. These results suggest that the low permeabilities of HFBI and lipid bilayers rely on different mechanisms. With their extremely low but adaptable permeability and high stability, HFBI membranes could be used as an osmotic pressure-insensitive barrier in situations where lipid membranes fail such as desalination membranes.
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Affiliation(s)
- Friederike Nolle
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Leonhard J. Starke
- Department
of Theoretical Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Alessandra Griffo
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
- Max
Planck School, Matter to Life, Jahnstraße 29, 69120 Heidelberg, Germany
- Max
Planck Institute for Medical Research Heidelberg, 69120 Heidelberg, Germany
| | | | - Karin Jacobs
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
- Max
Planck School, Matter to Life, Jahnstraße 29, 69120 Heidelberg, Germany
| | - Ralf Seemann
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Jean-Baptiste Fleury
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Jochen S. Hub
- Department
of Theoretical Physics, Saarland University, D-66123 Saarbrücken, Germany
| | - Hendrik Hähl
- Department
of Experimental Physics, Saarland University, D-66123 Saarbrücken, Germany
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Lolicato F, Saleppico R, Griffo A, Meyer A, Scollo F, Pokrandt B, Müller HM, Ewers H, Hähl H, Fleury JB, Seemann R, Hof M, Brügger B, Jacobs K, Vattulainen I, Nickel W. Cholesterol promotes clustering of PI(4,5)P2 driving unconventional secretion of FGF2. J Biophys Biochem Cytol 2022; 221:213511. [PMID: 36173379 PMCID: PMC9526255 DOI: 10.1083/jcb.202106123] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/22/2022] [Accepted: 08/30/2022] [Indexed: 11/22/2022] Open
Abstract
FGF2 is a cell survival factor involved in tumor-induced angiogenesis that is secreted through an unconventional secretory pathway based upon direct protein translocation across the plasma membrane. Here, we demonstrate that both PI(4,5)P2-dependent FGF2 recruitment at the inner plasma membrane leaflet and FGF2 membrane translocation into the extracellular space are positively modulated by cholesterol in living cells. We further revealed cholesterol to enhance FGF2 binding to PI(4,5)P2-containing lipid bilayers. Based on extensive atomistic molecular dynamics (MD) simulations and membrane tension experiments, we proposed cholesterol to modulate FGF2 binding to PI(4,5)P2 by (i) increasing head group visibility of PI(4,5)P2 on the membrane surface, (ii) increasing avidity by cholesterol-induced clustering of PI(4,5)P2 molecules triggering FGF2 oligomerization, and (iii) increasing membrane tension facilitating the formation of lipidic membrane pores. Our findings have general implications for phosphoinositide-dependent protein recruitment to membranes and explain the highly selective targeting of FGF2 toward the plasma membrane, the subcellular site of FGF2 membrane translocation during unconventional secretion of FGF2.
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Affiliation(s)
- Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg, Germany.,Department of Physics, University of Helsinki, Helsinki, Finland
| | | | - Alessandra Griffo
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Biophysical Engineering Group, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Annalena Meyer
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Federica Scollo
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Bianca Pokrandt
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | | | - Helge Ewers
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Hendrik Hähl
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | | | - Ralf Seemann
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Martin Hof
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague, Czech Republic
| | - Britta Brügger
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Karin Jacobs
- Department of Experimental Physics, Saarland University, Saarbrücken, Germany.,Max Planck School Matter to Life, Heidelberg, Germany
| | - Ilpo Vattulainen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
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Cai F, Zhao Z, Gao R, Chen P, Ding M, Jiang S, Fu Z, Xu P, Chenthamara K, Shen Q, Bayram Akcapinar G, Druzhinina IS. The pleiotropic functions of intracellular hydrophobins in aerial hyphae and fungal spores. PLoS Genet 2021; 17:e1009924. [PMID: 34788288 PMCID: PMC8635391 DOI: 10.1371/journal.pgen.1009924] [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: 05/11/2021] [Revised: 12/01/2021] [Accepted: 11/03/2021] [Indexed: 11/19/2022] Open
Abstract
Higher fungi can rapidly produce large numbers of spores suitable for aerial dispersal. The efficiency of the dispersal and spore resilience to abiotic stresses correlate with their hydrophobicity provided by the unique amphiphilic and superior surface-active proteins-hydrophobins (HFBs)-that self-assemble at hydrophobic/hydrophilic interfaces and thus modulate surface properties. Using the HFB-enriched mold Trichoderma (Hypocreales, Ascomycota) and the HFB-free yeast Pichia pastoris (Saccharomycetales, Ascomycota), we revealed that the rapid release of HFBs by aerial hyphae shortly prior to conidiation is associated with their intracellular accumulation in vacuoles and/or lipid-enriched organelles. The occasional internalization of the latter organelles in vacuoles can provide the hydrophobic/hydrophilic interface for the assembly of HFB layers and thus result in the formation of HFB-enriched vesicles and vacuolar multicisternal structures (VMSs) putatively lined up by HFBs. These HFB-enriched vesicles and VMSs can become fused in large tonoplast-like organelles or move to the periplasm for secretion. The tonoplast-like structures can contribute to the maintenance of turgor pressure in aerial hyphae supporting the erection of sporogenic structures (e.g., conidiophores) and provide intracellular force to squeeze out HFB-enriched vesicles and VMSs from the periplasm through the cell wall. We also show that the secretion of HFBs occurs prior to the conidiation and reveal that the even spore coating of HFBs deposited in the extracellular matrix requires microscopic water droplets that can be either guttated by the hyphae or obtained from the environment. Furthermore, we demonstrate that at least one HFB, HFB4 in T. guizhouense, is produced and secreted by wetted spores. We show that this protein possibly controls spore dormancy and contributes to the water sensing mechanism required for the detection of germination conditions. Thus, intracellular HFBs have a range of pleiotropic functions in aerial hyphae and spores and are essential for fungal development and fitness.
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Affiliation(s)
- Feng Cai
- The Key Laboratory of Plant Immunity, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, China
- Fungal Genomics Laboratory (FungiG), Nanjing Agricultural University, Nanjing, China
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Zheng Zhao
- Fungal Genomics Laboratory (FungiG), Nanjing Agricultural University, Nanjing, China
| | - Renwei Gao
- Fungal Genomics Laboratory (FungiG), Nanjing Agricultural University, Nanjing, China
| | - Peijie Chen
- Fungal Genomics Laboratory (FungiG), Nanjing Agricultural University, Nanjing, China
| | - Mingyue Ding
- Fungal Genomics Laboratory (FungiG), Nanjing Agricultural University, Nanjing, China
| | - Siqi Jiang
- Fungal Genomics Laboratory (FungiG), Nanjing Agricultural University, Nanjing, China
| | - Zhifei Fu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Science, Beijing, China
| | - Pingyong Xu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Science, Beijing, China
| | - Komal Chenthamara
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
| | - Qirong Shen
- The Key Laboratory of Plant Immunity, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, China
- * E-mail: (QS); (ISD)
| | - Günseli Bayram Akcapinar
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
- Department of Medical Biotechnology, Institute of Health Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Irina S. Druzhinina
- The Key Laboratory of Plant Immunity, Jiangsu Provincial Key Lab of Solid Organic Waste Utilization, Nanjing Agricultural University, Nanjing, China
- Fungal Genomics Laboratory (FungiG), Nanjing Agricultural University, Nanjing, China
- Institute of Chemical, Environmental and Bioscience Engineering (ICEBE), TU Wien, Vienna, Austria
- * E-mail: (QS); (ISD)
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Paananen A, Weich S, Szilvay GR, Leitner M, Tappura K, Ebner A. Quantifying biomolecular hydrophobicity: Single molecule force spectroscopy of class II hydrophobins. J Biol Chem 2021; 296:100728. [PMID: 33933454 PMCID: PMC8164047 DOI: 10.1016/j.jbc.2021.100728] [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] [Received: 11/20/2020] [Revised: 04/25/2021] [Accepted: 04/28/2021] [Indexed: 11/30/2022] Open
Abstract
Hydrophobins are surface-active proteins produced by filamentous fungi. The amphiphilic structure of hydrophobins is very compact, containing a distinct hydrophobic patch on one side of the molecule, locked by four intramolecular disulfide bridges. Hydrophobins form dimers and multimers in solution to shield these hydrophobic patches from water exposure. Multimer formation in solution is dynamic, and hydrophobin monomers can be exchanged between multimers. Unlike class I hydrophobins, class II hydrophobins assemble into highly ordered films at the air-water interface. In order to increase our understanding of the strength and nature of the interaction between hydrophobins, we used atomic force microscopy for single molecule force spectroscopy to explore the molecular interaction forces between class II hydrophobins from Trichoderma reesei under different environmental conditions. A genetically engineered hydrophobin variant, NCys-HFBI, enabled covalent attachment of proteins to the apex of the atomic force microscopy cantilever tip and sample surfaces in controlled orientation with sufficient freedom of movement to measure molecular forces between hydrophobic patches. The measured rupture force between two assembled hydrophobins was ∼31 pN, at a loading rate of 500 pN/s. The results indicated stronger interaction between hydrophobins and hydrophobic surfaces than between two assembling hydrophobin molecules. Furthermore, this interaction was stable under different environmental conditions, which demonstrates the dominance of hydrophobicity in hydrophobin-hydrophobin interactions. This is the first time that interaction forces between hydrophobin molecules, and also between naturally occurring hydrophobic surfaces, have been measured directly at a single-molecule level.
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Affiliation(s)
- Arja Paananen
- Industrial Biotechnology and Food, VTT Technical Research Centre of Finland Ltd, Espoo, Finland.
| | - Sabine Weich
- Department of Applied Experimental Biophysics, Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria
| | - Géza R Szilvay
- Industrial Biotechnology and Food, VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Michael Leitner
- Department of Applied Experimental Biophysics, Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria
| | - Kirsi Tappura
- Industrial Biotechnology and Food, VTT Technical Research Centre of Finland Ltd, Espoo, Finland
| | - Andreas Ebner
- Department of Applied Experimental Biophysics, Institute of Biophysics, Johannes Kepler University Linz, Linz, Austria.
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Hähl H, Griffo A, Safaridehkohneh N, Heppe J, Backes S, Lienemann M, Linder MB, Santen L, Laaksonen P, Jacobs K. Dynamic Assembly of Class II Hydrophobins from T. reesei at the Air-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9202-9212. [PMID: 31268722 DOI: 10.1021/acs.langmuir.9b01078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Class II hydrophobins are amphiphilic proteins produced by filamentous fungi. One of their typical features is the tendency to accumulate at the interface between an aqueous phase and a hydrophobic phase, such as the air-water interface. The kinetics of the interfacial self-assembly of wild-type hydrophobins HFBI and HFBII and some of their engineered variants at the air-water interface were measured by monitoring the accumulated mass at the interface via nondestructive ellipsometry measurements. The resulting mass vs time curves revealed unusual kinetics for a monolayer formation that did not follow a typical Langmuir-type of behavior but had a rather coverage-independent rate instead. Typically, the full surface coverage was obtained at masses corresponding to a monolayer. The formation of multilayers was not observed. Atomic force microscopy revealed formation and growth of non-fusing protein clusters at the interface. The mechanism of the adsorption was studied by varying the structure or charges of the protein or the ionic strength of the subphase, revealing that the lateral interactions between the hydrophobins play a role in their interfacial assembly. Additionally, a theoretical model was introduced to identify the underlying mechanism of the unconventional adsorption kinetics.
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Affiliation(s)
| | - Alessandra Griffo
- Department of Bioproducts and Biosystems , Aalto University , P.O. Box 16100, FI-00076 Aalto , Finland
| | | | | | - Sebastian Backes
- Federal Institute for Material Research and Testing (BAM) , Unter den Eichen 87 , 12205 Berlin , Germany
| | - Michael Lienemann
- VTT Technical Research Centre of Finland Ltd. , Espoo 02150 , Finland
| | - Markus B Linder
- Department of Bioproducts and Biosystems , Aalto University , P.O. Box 16100, FI-00076 Aalto , Finland
| | | | - Päivi Laaksonen
- Department of Bioproducts and Biosystems , Aalto University , P.O. Box 16100, FI-00076 Aalto , Finland
- HAMK Tech, Häme University of Applied Sciences , P.O. Box 230, Hämeenlinna 13101 , Finland
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