Arp2/3-dependent actin assembly shapes endosomes and promotes intracellular trafficking in fission yeast

Article Article scientifique Article Arp2/3-dependent actin assembly shapes endosomes and promotes intracellular trafficking in fission yeast eng 2026-03 author Melero Alejandro 0000-0003-4761-8230 author Basante Bedoya Miguel Angel 0000-0002-2396-6399 405319 Département de biologie moléculaire et cellulaire (MOCEL) author Muriel Lopez Olivia 0000-0003-2640-2342 778072 author Martin Sophie 0000-0002-5317-2557 403314 Département de biologie moléculaire et cellulaire (MOCEL) 10.1016/j.cub.2026.02.030 0960-9822 https://linkinghub.elsevier.com/retrieve/pii/S0960982226002204 Endosomes serve as crucial sorting centres that streamline the distribution of cell surface proteins. The early endosome receives traffic from both the plasma membrane (PM) and the Golgi, and orchestrates the redistribution of cargoes for recycling to the PM or through retrograde movement to the Golgi, and for degradation to late endosomes and lysosomes1. In animal cells and amoebae, Arp2/3 complex-mediated F-actin assembly plays critical roles in many aspects of endosome function, promoting both recycling and degradative trafficking routes2. Yeast models, which allowed dissection of the major membrane trafficking routes3, exhibit highly simplified endosomes, as shown in Saccharomyces cerevisiae, where the trans-Golgi network (TGN) functions as recycling endosome4. Furthermore, there is no reported role for Arp2/3 complex or F-actin in endomembrane remodelling in yeast cells, which lack Arp2/3 complex activators that function on animal endosomes5,6. Here, we examine the role of the Arp2/3 complex in the shape and function of fission yeast Schizosaccharomyces pombe endosomes. Through live-imaging and correlative light-electron tomography, we describe endosomes as dynamic tubulo-cisternal compartments, whose morphology requires branched actin, as inhibition of the Arp2/3 complex leads to endosome rounding. Though branched actin primarily localizes to endocytic patches, we show localization of the Arp2/3 complex and F-actin at endosomes for short bursts of time. Remarkably, Arp2/3-dependent actin assembly is critical to allow retrograde trafficking from the endosome to the degradative vacuole. Thus, Arp2/3 complex-dependent actin assembly has a deeply conserved role in shaping and promoting the function of the endomembrane trafficking system. Dewey 570 European Commission Mechanisms of gradient decoding in fission yeast 101019630 SexYeast EU H2020 7daed2ee-1311-4824-9df9-2e51260a966a Département de biologie moléculaire et cellulaire 16484 false 1410 Groupe Sophie Martin Current biology d31552b8-f66f-4059-a0bd-548780aef499 Article (Published version) Public 1-s2.0-S0960982226002204-main.pdf 12872017 application/pdf CC BY-4.0 c5ffff5f731a797911d17f67185c724838ed522bf348b312fe7724232af61335 openAccess Faculté des sciences / Section de biologie / Département de biologie moléculaire et cellulaire

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Arp2/3-dependent actin assembly shapes endosomes and promotes intracellular trafficking in fission yeast	Current biology			2026	5	9

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Basante Bedoya, Miguel Angel