The complex and dynamic nature of the nervous system requires exquisite cellular specialization. A large cellular diversity is a unique feature of the brain, distinguishing it from other organs, and making it harder to decipher its function. A large fraction of this diversity is expressed at synapses: the estimated 1015 synapses in the human brain can be classified into multiple subtypes based on their morphology, electrical properties, and, most importantly, their functional output.
What defines synapse identity? We follow the hypothesis that synapse identity can be defined by a unique and specific combination of proteins that are organized spatially according to pre-defined transcriptional and translational templates. Understanding how the synaptic proteome is composed and organized will promote the discovery of novel mechanism of neurotransmission, disease mechanisms in brain disorders, and allow to predict functionality in synapses that are experimentally inaccessible.