Evolutionarily diverged on-switch for actin assembly in fungal endocytosis
Clathrin-mediated endocytosis is a conserved eukaryotic trafficking process where an Arp2/3 complex-nucleated branched actin network provides force for vesicle formation. The mechanisms that initiate endocytic actin assembly are incompletely understood. In the fission yeast, Schizosaccharomyces pombe, actin assembly is initiated by Dip1, an Arp2/3 complex activator. In the budding yeast, Saccharomyces cerevisiae, the initiation of actin assembly has remained a mystery. Here, we show that S. cerevisiae Ldb17, the homolog of Dip1, functions as an on-switch for endocytic actin assembly. Unexpectedly, the regulation of Ldb17 is more complicated than that of constitutively active Dip1. Ldb17 is controlled by a coat protein, Sla1, via separate recruitment and activation steps. This regulation was likely lost in the S. pombe lineage, and this simplification may be related to other changes in actin assembly between these species. Our findings add a key missing piece in the understanding of endocytosis in S. cerevisiae and reveal an intriguing evolutionary tinkering of the actin on-switch.
Authors
- Nicolas Carvalho (ORCID: https://orcid.org/0000-0001-9812-9635)
- Andrea Picco (ORCID: https://orcid.org/0000-0003-2548-9183)
- Alphée Michelot (ORCID: https://orcid.org/0000-0003-2023-8094)
- Markku Hakala (ORCID: https://orcid.org/0000-0002-3485-6080)
- Anne-Sophie Rivier-Cordey (ORCID: https://orcid.org/0009-0004-6933-5738)
- Marko Kaksonen (ORCID: https://orcid.org/0000-0003-3645-7689)
- Christopher P. Toret (ORCID: https://orcid.org/0000-0001-8378-3706)
- Bagyashree VT (ORCID: https://orcid.org/0009-0002-5092-4108)
- Juliette Sebellin (ORCID: https://orcid.org/0009-0001-0012-4762)
- Fabina Binth Kandiyoth (ORCID: https://orcid.org/0009-0006-8193-3110)
Institutions
- University of Geneva (CH)
- Centre National de la Recherche Scientifique (FR)
- National University of Singapore (SG)
- Aix-Marseille Université (FR)
- Institut de Biologie du Développement Marseille (FR)
- Mechanobiology Institute (SG)
- Bridging Mechanobiology and Medicine (SG)
Publication Details
- Journal
- The Journal of Cell Biology
- Published
- 2026-10-28
- DOI
- https://doi.org/10.1083/jcb.202506135
- Primary Topic
- Cellular transport and secretion
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Research Foundation
- National University of Singapore
- National Research Foundation Singapore
- Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
- Université de Genève
- Mechanobiology Institute, Singapore