biostudies-literatureChung JHHS | NIH | National Institute of General Medical Sciences (NIGMS)NIGMS NIH HHSe2115129119https://www.ebi.ac.uk/biostudies/studies/S-EPMC9304009biostudies-literatureUnknown119(29)Eukaryotic cells contain branched actin networks that are essential for endocytosis, motility, and other key cellular processes. These networks, which are formed by filamentous actin and the Arp2/3 complex, must subsequently be debranched to allow network remodeling and to recycle the Arp2/3 complex. Debranching appears to be catalyzed by two different members of the actin depolymerizing factor homology protein family: cofilin and glial maturation factor (GMF). However, their mechanisms of debranching are only partially understood. Here, we used single-molecule fluorescence imaging of Arp2/3 complex and actin filaments under physiological ionic conditions to observe debranching by GMF and cofilin. We demonstrate that cofilin, like GMF, is an authentic debrancher independent of its filamentProceedings of the National Academy of Sciences of the United States of AmericaSingle-molecule analysis of actin filament debranching by cofilin and GMF.PMC9304009R35 GM134895R35GM134895R01 GM081648R01GM081648Goode BLGelles JChung JfalseSingle-molecule analysis of actin filament debranching by cofilin and GMF.Eukaryotic cells contain branched actin networks that are essential for endocytosis, motility, and other key cellular processes. These networks, which are formed by filamentous actin and the Arp2/3 complex, must subsequently be debranched to allow network remodeling and to recycle the Arp2/3 complex. Debranching appears to be catalyzed by two different members of the actin depolymerizing factor homology protein family: cofilin and glial maturation factor (GMF). However, their mechanisms of debranching are only partially understood. Here, we used single-molecule fluorescence imaging of Arp2/3 complex and actin filaments under physiological ionic conditions to observe debranching by GMF and cofilin. We demonstrate that cofilin, like GMF, is an authentic debrancher independent of its filament2022-01-01T00:00:00Z2022 Jul2025-04-04T09:30:38.962Z2025-04-04T09:30:38.962ZS-EPMC93040093585831410.1073/pnas.2115129119