Protein targeting: altering receptor kinase function in the brain.

Gene targeting has proved to be one of the most powerful techniques with which one can investigate molecular mechanisms that underlie complex phenomena such as learning and memory. Despite its popularity, however, concerns have been raised about this technique and alternative approaches have been sought. One such approach is protein targeting, which is based on the application of immunoadhesins, genetically engineered fusion proteins that exhibit functionally relevant target specificity. These immunoadhesins modulate the activity of not only a single receptor but of all receptors with homologous binding sites, which thereby eliminates the possibility of compensation by sister receptors. Furthermore, immunoadhesins can be used not only to impair but also to improve receptor function in the brain. Initial studies using immunoadhesins suggest that protein targeting might be a useful approach for analyzing the molecular mechanisms of brain function and behavior.