Speaker
Description
Biological condensates are membraneless organelles within the cell or the nucleus which perform an array of different tasks and typically consist of DNA/RNA and protein. Actin is a protein that exists in most eukaryotic cells and transitions between monomeric and filamentous states. In its filamentous state, actin forms networks, which perform vital tasks inside the cell. Recent research has shown interactions between biological condensates and cytoskeletal filaments, such as actin. The focus of these works was on morphological changes of condensates \cite{graham2023}, dynamics of condensates with cytoskeletal structures \cite{ nadezhdina2010} and polymerisation kinetics inside condensates \cite{bareesel2025,sun2025}. However, a full mathematical description of the cooperativity between condensates and actin polymerization is still missing. In this work we use a stochastic simulation algorithm to capture the polymerization kinetics of actin in a multicompartment system of condensates and dilute phase containing monomeric and filamentous actin. We show how condensates regulate the uptake of monomeric actin and how the enclosed environment of the condensate affects the polymerisation of actin. We make predictions about the number and length of polymerized actin filaments inside the condensate. This study, together with recent experimental findings, will help us understand how biological condensates are involved in the creation and maintenance of actin networks inside the cell.
Bibliography
@article{sun2025,
title = {Assembly of tight junction belts by {ZO1} surface condensation and local actin polymerization},
volume = {60},
issn = {15345807},
url = {https://linkinghub.elsevier.com/retrieve/pii/S1534580724007354},
doi = {10.1016/j.devcel.2024.12.012},
language = {en},
number = {8},
urldate = {2026-03-13},
journal = {Developmental Cell},
author = {Sun, Daxiao and Zhao, Xueping and Wiegand, Tina and Martin-Lemaitre, Cecilie and Borianne, Tom and Kleinschmidt, Lennart and Grill, Stephan W. and Hyman, Anthony A. and Weber, Christoph and Honigmann, Alf},
month = apr,
year = {2025},
pages = {1234--1250.e6},
}
@misc{bareesel2025,
title = {Membrane protein condensates polymerize actin and form filopodia},
copyright = {http://creativecommons.org/licenses/by-nc-nd/4.0/},
url = {http://biorxiv.org/lookup/doi/10.1101/2025.10.09.681077},
doi = {10.1101/2025.10.09.681077},
language = {en},
urldate = {2026-03-13},
author = {Bareesel, Shannon and Böddeker, Thomas J. and Bintig, Willem and Nagy-Herczeg, Domonkos and Ruwolt, Max and Syropoulou, Vasiliki and Kroon, Cristina and Kreis, Patricia and Wegmann, Susanne and Szczepek, Michal and Spahn, Christian M.T. and Scheerer, Patrick and Leondaritis, George and Liu, Fan and Knorr, Roland L. and Eickholt, Britta J.},
month = oct,
year = {2025},
}
@article{graham2023,
title = {Liquid-like {VASP} condensates drive actin polymerization and dynamic bundling},
volume = {19},
copyright = {2023 The Author(s), under exclusive licence to Springer Nature Limited},
issn = {1745-2481},
url = {https://www.nature.com/articles/s41567-022-01924-1},
doi = {10.1038/s41567-022-01924-1},
language = {en},
number = {4},
urldate = {2026-03-13},
journal = {Nature Physics},
author = {Graham, Kristin and Chandrasekaran, Aravind and Wang, Liping and Ladak, Aly and Lafer, Eileen M. and Rangamani, Padmini and Stachowiak, Jeanne C.},
month = apr,
year = {2023},
keywords = {Intrinsically disordered proteins, Phase transitions and critical phenomena, Self-assembly},
pages = {574--585},
}
@article{nadezhdina2010,
title = {Microtubules govern stress granule mobility and dynamics},
volume = {1803},
copyright = {https://www.elsevier.com/tdm/userlicense/1.0/},
issn = {01674889},
url = {https://linkinghub.elsevier.com/retrieve/pii/S0167488909002985},
doi = {10.1016/j.bbamcr.2009.12.004},
language = {en},
number = {3},
urldate = {2026-03-13},
journal = {Biochimica et Biophysica Acta (BBA) - Molecular Cell Research},
author = {Nadezhdina, Elena S. and Lomakin, Alexis J. and Shpilman, Alexey A. and Chudinova, Elena M. and Ivanov, Pavel A.},
month = mar,
year = {2010},
pages = {361--371},
}
