Nedd8 conjugation controls cytoskeleton dynamics to promote early neuronal development

VOLG ANNETTE ; VERCELLI CLAUDIA; BORDENAVE MATIN; STEFANI FERNANDO; BECERRA, RAQUEL; GIUSTI SEBASTIAN; REFOJO DAMIÁN

Puerto Varas

Workshop; IUBMB Focused Meeting on Emerging Concepts of the Neuronal Cytoskeleton; 2017

Neuronal development is controlled by signaling cascades tightly controlled a myriad of posttranslational modifications. The role of ubiquitin has been well stablished but the function of the family of ubiquitin-like proteins remains poorly understood.Nedd8 is the UBL with the highest homology to Ub and we recently demonstrate that is highly abundant in the brain and is critical for synapse formation and maintenance. Blocking Nedd8 conjugation with genetic and pharmacological tools reduced axonal and dendritic growth both in cell culture systems and in utero electroporation approaches. These effects were partially reverted by Cytochalasin D, and low doses of Taxol. These results suggest that cytoskeleton dynamics is involved in the effects of Nedd8 on axodendritic growth.To identify the structural details underlying the effects of Nedd8 we employed superresolution microscopy.Neddylation inhibition strongly reduced microtubular dynamics, triggers ectopic lamellipodia formation and increase growth cone size in early neurons. Accordingly, spinning disk confocal studies indicate that indeed blocking neddylation with the pharmachological inhibitor MLN4924 severely decreased microtubular polimeryzation.Finally, in biochemical screenings we identified several neddylated targets related to the cytoskeleton structure and function. The potential involvement of those targets in the effects of Nedd8 will be discussed.