Role of RhoD GTPase in neuronal development

QUASSOLLO, GONZALO; MARTIN, JOSEFÍNA; BISBAL, MARIANO

Dresden

Otro; EMBO practical course: Mouse genome engineering; 2019

European Molecular Biology Organization (EMBO)

Neurons are highly polarized cells typically extending a long thin axon and multiple short branched dendrites. These specialized compartments are developed through the coordination of cellular and molecular mechanisms in order to ensure the proper functioning of the nervous system, and are highly regulated by several small Rho GTPases with their effectors controlling different aspects of neuronal morphology. Among others, these events include actin and microtubules cytoskeleton assembly, and the addition of membrane in neuron specialized regions. Even though most of studies have been focused on classical Rho GTPases (RhoA, Rac1 and Cdc42), other less studied members of this family such as RhoD suggest to have unique effects on cytoskeleton and membrane dynamics. In this study we have analyzed the role of RhoD during the development of axonal polarization and neurite extension. Our results reveal that hippocampal cultures highly express mRNA codifying for RhoD protein quantified by qPCR. Besides, the expression of RhoD active mutant in hippocampal neurons induces the generation of multiple axons and increase neuritic outgrowth and complexity. These results suggest that RhoD plays an important role during neuronal differentiation and neuritic outgrowth. In addition, we have designed an unimolecular activity RhoD biosensor based on resonance energy transfer (FRET) to study the space-time dynamics of this Rho GTPase in fibroblasts and neurons. Finally, we have evaluated how RhoD affects different dynamic parameters of microtubule cytoskeleton in fibroblast cells.