AUTHOR=Mortal Simone , Iseppon Federico , Perissinotto Andrea , D'Este Elisa , Cojoc Dan , Napolitano Luisa M. R. , Torre Vincent TITLE=Actin Waves Do Not Boost Neurite Outgrowth in the Early Stages of Neuron Maturation JOURNAL=Frontiers in Cellular Neuroscience VOLUME=11 YEAR=2017 URL=https://www.frontiersin.org/journals/cellular-neuroscience/articles/10.3389/fncel.2017.00402 DOI=10.3389/fncel.2017.00402 ISSN=1662-5102 ABSTRACT=

During neurite development, Actin Waves (AWs) emerge at the neurite base and move up to its tip, causing a transient retraction of the Growth Cone (GC). Many studies have shown that AWs are linked to outbursts of neurite growth and, therefore, contribute to the fast elongation of the nascent axon. Using long term live cell-imaging, we show that AWs do not boost neurite outgrowth and that neurites without AWs can elongate for several hundred microns. Inhibition of Myosin II abolishes the transient GC retraction and strongly modifies the AWs morphology. Super-resolution nanoscopy shows that Myosin IIB shapes the growth cone-like AWs structure and is differently distributed in AWs and GCs. Interestingly, depletion of membrane cholesterol and inhibition of Rho GTPases decrease AWs frequency and velocity. Our results indicate that Myosin IIB, membrane tension, and small Rho GTPases are important players in the regulation of the AW dynamics. Finally, we suggest a role for AWs in maintaining the GCs active during environmental exploration.