- Physical Review Journals
All JournalsPhysics Magazine

PRX Life

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access

Novel Analysis Method for Condensate Wetting Identifies Charge-Dependent Tau-Membrane Interactions

Katharina Sporbeck1,2,*, Subhadip Ghosh3,*, Rithika Sankar2, Boglarka Nagy-Herczeg2, Susanne Wegmann2,4, Jaime Agudo-Canalejo3,†, and Roland L. Knorr1,5,6,7,‡

  • *These authors contributed equally to this work.
  • †Contact author: j.agudo-canalejo@ucl.ac.uk
  • ‡Contact author: roland.knorr@uni-koeln.de
PDF

PRX Life 4, 033014 – Published 14 August, 2026

DOI: https://doi.org/10.1103/8x47-4t2b

Abstract

Condensed biomolecular phases are fundamental compartments in cells and play intricate roles for cellular organization. Although often referred to as “membraneless organelles,” evidence has emerged that condensates associate with membranes through wetting interactions, which are physiologically important but not well understood. Here we report a novel method that provides a detailed description of how condensates interact with surfaces. Combining technically advantageous flat membranes and reconstituted condensates, we developed an accurate method that automatically analyzes the three-dimensional geometry of single, μm-sized condensates acquired as multicondensate confocal image stacks using 96-well plates. We validated our computational routine by quantifying wetting of in vitro and in silico condensates for precisely controlled solution and supported lipid membrane biochemistries. Further, we applied our method to analyze the wetting of condensates formed from the Alzheimer disease-associated protein tau in its phosphorylated and nonphosphorylated forms. Our results demonstrate that both membrane charge and tau posttranslational modifications affect wetting and that our method allows building a systematic, quantitative wetting database, which catalogues conditions controlling wetting in multiple dimensions. We anticipate that upscaled in a high-throughput pipeline, our screening approach will efficiently support efforts to construct a comprehensive wetosome database, which will unravel the mechanisms underlying condensate-membrane interactions and, thus, decipher the molecular grammar governing wetting.

View figure in article

Physics Subject Headings (PhySH)

Collections

This article appears in the following collection:

Collection on Physics of Biomolecular Condensates

From the fundamentals of phase separation, dynamics and structure of condensates in biological settings, to advanced imaging methods, this special collection presented by PRX Life showcases exciting and timely work on the physics of biomolecular condensates.

This Invited Collection is coordinated by PRX Life Associate Editor Christoph Weber, in consultation with Jerelle Joseph, Simon Alberti, and Tanja Mittag. Every article published in this collection underwent a rigorous peer review process, adhering to the same high standards applied to all papers handled by the journal. The PRX Life editorial team managed the peer review and made all editorial decisions.

Article Text

Supplemental Material

References (37)

  1. Y. Shin and C. P. Brangwynne, Liquid phase condensation in cell physiology and disease, Science 357, eaaf4382 (2017).
  2. S. F. Banani, H. O. Lee, A. A. Hyman, and M. K. Rosen, Biomolecular condensates: Organizers of cellular biochemistry, Nat. Rev. Mol. Cell Biol. 18, 285 (2017).
  3. J. A. Ditlev, L. B. Case, and M. K. Rosen, Who's in and who's out—Compositional control of biomolecular condensates, J. Mol. Biol. 430, 4666 (2018).
  4. H. Kusumaatmaja, A. I. May, and R. L. Knorr, Intracellular wetting mediates contacts between liquid compartments and membrane-bound organelles, J. Cell Biol. 220, e202103175 (2021).
  5. Y. Wang, S. Li, M. Mokbel, A. I. May, Z. Liang, Y. Zeng, W. Wang, H. Zhang, F. Yu, K. Sporbeck, et al., Biomolecular condensates mediate bending and scission of endosome membranes, Nature (London) 634, 1204 (2024).
  6. J. Agudo-Canalejo, S. W. Schultz, H. Chino, S. M. Migliano, C. Saito, I. Koyama-Honda, H. Stenmark, A. Brech, A. I. May, N. Mizushima, and R. L. Knorr, Wetting regulates autophagy of phase-separated compartments and the cytosol, Nature (London) 591, 142 (2021).
  7. L. Hauer, K. Sporbeck, J. F. McKenna, D. Puchkov, A. I. May, L. Frigerio, R. L. Knorr, and A. H. Bahrami, Condensate-mediated shape transformations of cellular membranes by capillary forces, Proc. Natl. Acad. Sci. USA 123, e2424126123 (2026).
  8. D. J. Klionsky, G. Petroni, R. K. Amaravadi, E. H. Baehrecke, A. Ballabio, P. Boya, J. M. Bravo-San Pedro, K. Cadwell, F. Cecconi, A. M. Choi, et al., Autophagy in major human diseases, EMBO J. 40, EMBJ2021108863 (2021).
  9. P. Li, J. Chen, X. Wang, Z. Su, M. Gao, and Y. Huang, Liquid-liquid phase separation of tau: Driving forces, regulation, and biological implications, Neurobiol. Disease 183, 106167 (2023).
  10. H. Braak and E. Braak, Neuropathological stageing of Alzheimer-related changes, Acta Neuropathologica 82, 239 (1991).
  11. F. Liu, Z. Liang, J. Shi, D. Yin, E. El-Akkad, I. Grundke-Iqbal, K. Iqbal, and C.-X. Gong, PKA modulates GSK−3β-and cdk5-catalyzed phosphorylation of tau in site-and kinase-specific manners, FEBS Lett. 580, 6269 (2006).
  12. S. Wegmann, B. Eftekharzadeh, K. Tepper, K. M. Zoltowska, R. E. Bennett, S. Dujardin, P. R. Laskowski, D. MacKenzie, T. Kamath, C. Commins, et al., Tau protein liquid–liquid phase separation can initiate tau aggregation, EMBO J. 37, EMBJ201798049 (2018).
  13. S. Ambadipudi, J. Biernat, D. Riedel, E. Mandelkow, and M. Zweckstetter, Liquid–liquid phase separation of the microtubule-binding repeats of the Alzheimer-related protein tau, Nat. Commun. 8, 275 (2017).
  14. Y. Lin, Y. Fichou, Z. Zeng, N. Y. Hu, and S. Han, Electrostatically driven complex coacervation and amyloid aggregation of tau are independent processes with overlapping conditions, ACS Chem. Neurosci. 11, 615 (2020).
  15. J. Hochmair, C. Exner, M. Franck, A. Dominguez-Baquero, L. Diez, H. Brognaro, M. L. Kraushar, T. Mielke, H. Radbruch, S. Kaniyappan, et al., Molecular crowding and RNA synergize to promote phase separation, microtubule interaction, and seeding of tau condensates, EMBO J. 41, EMBJ2021108882 (2022).
  16. A. Hernández-Vega, M. Braun, L. Scharrel, M. Jahnel, S. Wegmann, B. T. Hyman, S. Alberti, S. Diez, and A. A. Hyman, Local nucleation of microtubule bundles through tubulin concentration into a condensed tau phase, Cell Rep. 20, 2304 (2017).
  17. K. W. Chung, Advances in understanding of the role of lipid metabolism in aging, Cells 10, 880 (2021).
  18. H. Sunshine and M. L. Iruela-Arispe, Membrane lipids and cell signaling, Curr. Opin. Lipidology 28, 408 (2017).
  19. S. Srinivasan, G. H. McKinley, and R. E. Cohen, Assessing the accuracy of contact angle measurements for sessile drops on liquid-repellent surfaces, Langmuir 27, 13582 (2011).
  20. E. Atefi, J. A. Mann, Jr., and H. Tavana, A robust polynomial fitting approach for contact angle measurements, Langmuir 29, 5677 (2013).
  21. J. Holland, A. A. Castrejón-Pita, R. Tuinier, D. G. Aarts, and T. J. Nott, Surface tension measurement and calculation of model biomolecular condensates, Soft Matter 19, 8706 (2023).
  22. M. Ijavi, R. W. Style, L. Emmanouilidis, A. Kumar, S. M. Meier, A. L. Torzynski, F. H. Allain, Y. Barral, M. O. Steinmetz, and E. R. Dufresne, Surface tensiometry of phase separated protein and polymer droplets by the sessile drop method, Soft Matter 17, 1655 (2021).
  23. J. Holland, T. J. Nott, and D. G. A. L. Aarts, Intrinsic hydrophobicity of IDP-based biomolecular condensates drives their partial drying on membrane surfaces, J. Chem. Phys. 162, 115101 (2025).
  24. J. D. Unsay, K. Cosentino, K. Sporbeck, and A. J. García-Sáez, Pro-apoptotic cBid and Bax exhibit distinct membrane remodeling activities: An AFM study, Biochim. Biophys. Acta (BBA) - Biomembranes 1859, 17 (2017).
  25. H. Y. Erbil and R. A. Meric, Evaporation of sessile drops on polymer surfaces: Ellipsoidal cap geometry, J. Phys. Chem. B 101, 6867 (1997).
  26. V. A. Lubarda and K. A. Talke, Analysis of the equilibrium droplet shape based on an ellipsoidal droplet model, Langmuir 27, 10705 (2011).
  27. G. Whyman and E. Bormashenko, Oblate spheroid model for calculation of the shape and contact angles of heavy droplets, J. Colloid Interface Sci. 331, 174 (2009).
  28. M. Linkert, C. T. Rueden, C. Allan, J.-M. Burel, W. Moore, A. Patterson, B. Loranger, J. Moore, C. Neves, D. MacDonald, A. Tarkowska, C. Sticco, E. Hill, M. Rossner, K. W. Eliceiri, and J. R. Swedlow, Metadata matters: Access to image data in the real world, J. Cell Biol. 189, 777 (2010).
  29. J. G. Huddleston, H. D. Willauer, and R. D. Rogers, Phase diagram data for several PEG+ salt aqueous biphasic systems at 25 °C, J. Chem. Eng. Data 48, 1230 (2003).
  30. S. Bonnassieux, R. Pandya, D. A. Skiba, D. Degoulange, D. Petit, P. Seem, R. P. Cowburn, B. M. Gallant, and A. Grimaud, Revisiting the driving force inducing phase separation in PEG–phosphate aqueous biphasic systems, Faraday Discuss. 253, 181 (2024).
  31. A. Testa, M. Dindo, A. A. Rebane, B. Nasouri, R. W. Style, R. Golestanian, E. R. Dufresne, and P. Laurino, Sustained enzymatic activity and flow in crowded protein droplets, Nat. Commun. 12, 6293 (2021).
  32. See Supplemental Material at http://link.aps.org/supplemental/10.1103/8x47-4t2b for additional figures showing volume distribution of condensates (Fig. S1), further analysis of in silico condensates (Fig. S2), and global fits for the results in Fig. 4 of the main text (Fig. S3).
  33. R. Tan, A. J. Lam, T. Tan, J. Han, D. W. Nowakowski, M. Vershinin, S. Simó, K. M. Ori-McKenney, and R. J. McKenney, Microtubules gate tau condensation to spatially regulate microtubule functions, Nat. Cell Biol. 21, 1078 (2019).
  34. C. Tchounwou, A. J. Jobanputra, D. Lasher, B. J. Fletcher, J. Jacinto, A. Bhaduri, R. L. Best, W. S. Fisher, K. K. Ewert, Y. Li, S. C. Feinstein, and C. R. Safinya, Mixtures of intrinsically disordered neuronal protein tau and anionic liposomes reveal distinct anionic liposome-tau complexes coexisting with tau liquid–liquid phase-separated coacervates, Langmuir 40, 21041 (2024).
  35. R. Brandt, J. Léger, and G. Lee, Interaction of tau with the neural plasma membrane mediated by tau's amino-terminal projection domain, J. Cell Biol. 131, 1327 (1995).
  36. T. Lu, S. Liese, B. S. Visser, M. H. I. van Haren, W. P. Lipiński, W. T. S. Huck, C. A. Weber, and E. Spruijt, Controlling multiphase coacervate wetting and self-organization by interfacial proteins, J. Am. Chem. Soc. 147, 22622 (2025).
  37. K. Sporbeck, S. Ghosh, R. Sankar, B. Nagy-Herczeg, S. Wegmann, J. Agudo-Canalejo, and R. L. Knorr, Data and code for: A novel analysis method for condensate wetting identifies charge-dependent tau-membrane interactions, Zenodo, 2026, https://doi.org/10.5281/zenodo.21067681.

Outline

Information

PRX Life 4, 033014– Published 14 August, 2026
  • Received 23 December 2025
  • Accepted 26 June 2026
Crossmark - Check for updates button
Creative Commons Logo

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation