抄録
We address biological questions concerning spatio-temporal patterns of signaling by EGF and astrocytic contact. First, the pattern of EGF signaling was visualized using fluorescent indicators for Ras activation and tyrosine phosphorylation in single live COS cells following local stimulation. Ligand-independent propagation of EGF signaling occured only when the receptor density on the plasma membrane was high, such as in carcinoma cells. Second, local contact with astrocytes via integrin receptors elicited PKC activation in individual dissociated neurons cultured in astrocyte-conditioned medium. The PKC activation, initially focal, soon spread throughout the entire neuron, leading to global neuronal maturation.
