During development cell surface proteins allow to communicate with the surrounding cells and the extracellular matrix for proper proliferation, migration, differentiation and contact formation in the complex network. But also in the mature and aging nervous system they are needed for electrical activity, neuronal communication, survival and even regeneration.
Alterations in cell surface protein signalling have been implicated in the pathogenesis of neurodegenerative disorders such as motor neuron diseases, PD and Alzheimer disease (AD) but also in diseases such depression, attention-deficit/hyperactivity disorder (ADHD) and schizophrenia. There are many cross-talks of different cell surface proteins on neuronal membranes which even can be different concerning their localization in axons, dendrites, synapses and other specialized membrane structures. In addition, they are connected with the intraneuronal processes by a large amount of signalling and regulatory pathways. So far our knowledge about neuronal cell surface protein interaction, signalling and their physiological function is still limited.