Role of atypical GTPase RhoD during the development of neuronal polarity

BISBAL M; MARTIN J; QUASSOLLO G

Córdoba

Workshop; Sociedad Argentina de Investigación en Neurociencias (SAN) XXXIII Annual Meeting.; 2018

Sociedad Argentina de Investigación en Neurociencias

Neurons are highly polarized cells typically extending a long thin axon and multiple short brancheddendrites. These specialized compartments are developed through the coordination of cellular andmolecular mechanisms in order to ensure the proper functioning of the nervous system, and arehighly regulated by several small Rho GTPases with their effectors controlling different aspects ofneuronal morphology. Among others, these events include actin and microtubules cytoskeletonassembly, and the addition of membrane in neuron specialized regions. Even though most ofstudies have been focused on classical Rho GTPases (RhoA, Rac1 and Cdc42), other less studiedmembers of this family such as RhoD suggest to have unique effects on cytoskeleton andmembrane dynamics. In this study we have analyzed the role of RhoD during the development ofaxonal polariza􀀁on and neurite extension. Our results reveal that hippocampal cultures highlyexpress messenger ARN codifying for RhoD protein quan􀀁fied by qPCR. Besides, the expression ofRhoD active mutant in hippocampal neurons induces the genera􀀁on of multiple axons and increaseneuritic outgrowth and complexity. These results suggest that RhoD plays an important role duringneuronal differentiation and neuritic outgrowth. In addition, we have designed an unimolecularactivity RhoD biosensor based on resonance energy transfer (FRET) to study the space-timedynamics of this Rho GTPase in cultured hippocampal neurons. Finally, we have evaluated howRhoD affects different dynamic parameters of microtubules cytoskeleton in fibroblast cells.