Localized Myosin II Activity Regulates Assembly and Plasticity of the Axon Initial Segment

Abstract : Highlights d Phosphorylated myosin light chain (pMLC) is enriched in axon initial segments (AISs) d pMLC is associated with the actin rings in the AIS, as imaged by STORM d Inhibiting MLC phosphorylation and myosin II activity blocks assembly of the AIS d pMLC is rapidly lost with depolarization, destabilizing actin and the AIS In Brief Berger et al. demonstrate that pMLC, a key regulator of contractile myosin II, is enriched in the axon initial segment (AIS) and is associated with actin rings. They show that pMLC and myosin II have major roles in AIS assembly and activity-dependent plasticity.