A simple dynamic model that accounts for regulation of neuronal polarity

It has been shown that competing molecular interactions of atypical protein kinase C isoforms regulate neuronal polarity. For instance, silencing one particular isoform known as protein kinase M- ζ or overexpression of a second isoform known as protein kinase C- λ in hippocampal neurons alters neuronal polarity, resulting in neurons with extra axons. In contrast, the overexpression of protein kinase M- ζ prevents axon specification. These data suggest that antagonistic competition between PKC isoforms could contribute to the development of polarity and axon specification. Here, an excitatory and inhibitory non-linear network model is employed to describe neuronal polarity under different conditions. The model shifts the balance of excitation and inhibition to replicate a variety of scenarios during axon outgrowth, which are then compared with experimental results.