Actin polymerization counteracts prewetting of N-WASP on supported lipid bilayers

• 成果类型: Article
• 署名作者: Wiegand, Tina; Liu, Jinghui; Vogeley, Lutz; LuValle-Burke, Isabel; Geisler, Jan; Fritsch, Anatol W.; Hyman, Anthony A.; Grill, Stephan W.
• 署名单位: Max Planck Society; Max Planck Society; Technische Universitat Dresden
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12283
• DOI: 10.1073/pnas.2407497121
• 发表日期: 2024-12-10
• 关键词: phase-separation; activation; nucleation; nucleotide; molecules; cdc42

摘要

Cortical condensates, transient punctate-like structures rich in actin and the actin nucleation pathway member Neural Wiskott-Aldrich syndrome protein (N-WASP), form during activation of the actin cortex in the Caenorhabditis elegans oocyte. Their emergence and spontaneous dissolution is linked to a phase separation process driven by chemical kinetics. However, the mechanisms that drive the onset of cortical condensate formation near membranes remain unexplored. Here, using a reconstituted phase separation assay of cortical condensate proteins, we demonstrate that the key component, N-WASP, can collectively undergo surface condensation on supported lipid bilayers via a prewetting transition. Actin partitions into the condensates, where it polymerizes and counteracts the N-WASP prewetting transition. Taken together, the dynamics of condensate-assisted cortex formation appear to be controlled by a balance between surface-assisted condensate formation and polymer-driven condensate dissolution. This opens perspectives for understanding how the formation of complex intracellular structures is affected and controlled by phase separation.