A dynamic formin-dependent deep F-actin network in axons

• DOI: 10.1083/jcb.201506110
• Publication Date: 2015-07-28T01:01:31Z
• Authors: Archan Ganguly; Yong Tang; Lina Wang; Kelsey Ladt; Jonathan Loi; Bénédicte Dargent; Christophe Leterrier; Subhojit Roy
• Keywords: Formins; Actin remodeling; Lamellipodium; MDia1; Colocalization

Although actin at neuronal growth cones is well-studied, much less known about organization and dynamics along axon shafts presynaptic boutons. Using probes that selectively label filamentous-actin (F-actin), we found focal “actin hotspots” axons—spaced ∼3–4 µm apart—where undergoes continuous assembly/disassembly. These foci are a nidus for vigorous polymerization, generating long filaments spurting bidirectionally axons—a phenomenon call trails.” Super-resolution microscopy reveals intra-axonal deep in addition to the subplasmalemmal rings” described recently. F-actin hotspots colocalize with stationary axonal endosomes, blocking vesicle transport diminishes trails, suggesting mechanistic links between vesicles kinetics. Actin trails formin—but not Arp2/3—dependent help enrich Finally, formin inhibition dramatically disrupts synaptic recycling. Collectively, available data suggest two-tier axons, stable providing mechanical support plasma membrane dynamic "actin trails" flexible cytoskeletal network putative physiological roles.