TITLE:
Rho and Ras GTPases in semaphorin-mediated neuronal development
AUTHORS:
Lifei Fan, Morigen
KEYWORDS:
Small Rho GTPase; Semaphorin Signalling; Neurite Development
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.4 No.1A,
January
31,
2013
ABSTRACT: Neurons are highly polarized cells with a single long
axon and multiple dendrites, all of which are actinrich structures. The
precise regulation of neuronal cell morphology is a fundamental aspect of
neurobiology. The major role of Rho GTPases, which is conserved in all
eukaryotes, is to regulate the actin and microtubule
cytoskeleton. Therefore theRhoGTPases are key regulators of neuronal morphology during development
besides their canonical functions in actin cytoskeletal regulation, cell
migration and cell cycle progression. Semaphorins are a family of secreted or transmembrane proteins, which function through their receptor plexins and/or neuropilins to act as the repulsive or
attractive guidance cues for axons and dendrites. It has been demonstrated
that the fully activetion of plexins appears to be dependent on the binding of RhoGTPases
to theRhobinding domain (RBD) and Semaphorin to the extracellular region. Here,
we summarize the functions of the small Rho GTPases in two well-studied vertebrate
Semaphorins, Sema3Aand
Sema4D; and the potential roles of the small Rho GTPases in some poorly-studied
vertebrate Semaphorins Sema5A,
Sema6Aand Sema7A. We also summarize the functions of
different members of Ras family, R-Ras, M-Ras and Rap, in Semaphorin signalling
pathways as well.