Ras-related and MAPK signalling in neuronal plasticity and memory formation

Ras-related guanosine triphosphatases (GTPases) couple receptor activity to a number of intracellular signalling events culminating in the control of cell morphology and gene transcription. In culture cells, the best-understo od Ras-dependent signalling pathway involves the mitogen-activated protein kinase/extracellular-regulated kinase (MAPK/ERK) cascade. A growing body of evidence has recently been accumulating to suggest a crucial role of Ras a nd MAPK signalling in neuronal functions connected to synaptic plasticity. In the present review article we discuss the experimental basis supporting the notion that the Ras/MAPK pathway interacts with other synaptic mechanis ms to regulate invertebrate and vertebrate behavioural responses such as th ose implicated in learning and memory processes.