Protein interactome of the chemical synapse

 

Central to all neuronal functions are the trillions of chemical synapses within the human brain that transmit chemical signals. This process is performed and regulated by complex networks of proteins in the pre- and post- synaptic termini. In the past ten years efforts in synaptic-proteomics have been focused on identifying the constituents of synaptic sub-compartments; the synaptic vesicle, pre-synaptic active site and post-synaptic density. Over 2000 gene products have been identified in the chemical synapse, but the binary interactions between these players have not previously been studied on a large scale. To gain more insight into multi-protein complexes formed at the synapse we have adopted a high-throughput screening strategy; approximately 1000 proteins are being tested for pair wise interaction using the yeast-2-hybrid technique.

 

Fig. 1: Yeast-2-hybrid assay

 

Selection of interacting protein pairs for validation will be based upon a scoring system which takes into account six factors: 1) known interactions between orthologues, 2) the presence of domains known to interact in each of the proteins, 3) co-expression, 4) co-localisation, 5) participation in the same biological process and 6) distance in an interaction network made up of all known interactions. High confidence interactions will be validated using the Lumier method, in which the interacting proteins are transiently co-expressed and then co-immunoprecipitated.

Fig. 2: Lumier assay

 

The protein interaction network generated and validated by this study could provide insight into synapse dysfunction, which is central to the etiology and progression of neurological disorders including neurodegeneration, autism and schizophrenia.

Fig. 3: PPI network of the synapse

 

Project coordinator and contact:

Angeli Moeller, PhD (angeli.moeller@mdc-berlin.de)

 

Associated projects:

HTT in the synapse: Philipp Trepte (philipp.trepte@mdc-berlin.de)

Split-ubiquitin Y2H: Matthias Könn (matthias.koenn@mdc-berlin.de)

 

Collaborators:

Development of scoring system: Martin Schaefer, (Computational Biology and Data Mining AG Andrade)

 

Funding:

The research leading to these results has received funding from the European Union Seventh Framework Programme under grant agreements:

HEALTH-F2-2009-241498 ("EUROSPIN" project) http://www.eurospin.mpg.de/index.html and

HEALTH-F2-2009-242167 (“SynSys” project) http://www.synsys.eu/