Tiam1 and the neurite elongation equilibrium

The role of the guanine nucleotide exchange factor Tiam1 has long been known to stimulate the outgrowth of neurons (see here) by shifting the Rac / Rho actin polymerization equilibrium (see here) towards Rac. Now Fard et al. have used RNA interference in cell culture to show that Tiam1 is specifically associated with NGF/TrkA-dependent neurite elongation. Here is the mechanism they propose, involving tyrosine kinase receptors:

RNA interference is a useful technique for evaluating mechanisms. As opposed to pure gene knock-out studies, it can allow for the evaluation of a more dose-dependent relationship.

Reference

Shirazi Fard S, Kele J, Vilar M, Paratcha G, Ledda F (2010) Tiam1 as a Signaling Mediator of Nerve Growth Factor-Dependent Neurite Outgrowth. PLoS ONE 5(3): e9647. doi:10.1371/journal.pone.0009647