Exosome Gene Ontology Annotation Initiative

Exosomes are small vesicles (30-100 nm in diameter) found in most biological fluids. Since their discovery 25 years ago, emergent exosome functions have included communication, immune system regulation, involvement in heart-related processes and in a variety of cancers. Exosomes and their molecular cargo have been suggested to be diagnostic biomarkers of diseases. Functional analyses of the biological roles of exosomal proteins from different sources is key in understanding how exosomes can be used as biomarkers for diseases.

This initiative, undertaken by the UniProt curators at the EBI, involves the manual assignment of GO annotations to human exosomal proteins by curators reading the scientific literature and assigning to the proteins GO terms that describe their biological roles. Curators working on this project are requesting new GO terms specific to exosome protein biology to fully capture literature findings.

As well as increasing the number and quality of experimental annotations available to human exosomal proteins, curators  creating the annotations capture cell and tissue type dependencies, substrates and regulation targets of exosomal proteins. This is invaluable in describing the literature findings of exosomal proteins, as studies have shown the cell or tissue origin of an exosome affect its proteomic composition and therefore the functions it performs.  Capturing the functional and location information of exosomal proteins using GO allows complex questions to be asked of the data, both by human and computer.

The manual annotation initiative is working closely with laboratory-based researchers (Dr S Mathivanan - La Trobe InstituteDr A Kalea - UCL) and exosome databases like Exocarta (http://www.exocarta.org/) and Vesiclepedia (http://microvesicles.org/) to identify target proteins for focused annotation as well as interpretation of exosome experimental methodology.

The current list of proteins being prioritised for annotation by the Exosome Gene Ontology Annotation Initiative is located here.

If you would like to know more about this initiative, or would like to contribute, please contact goa@ebi.ac.uk