OntoPIN: an ontology-annotated PPI database

Protein-protein interaction (PPI) data stored in publicly available databases are queried by the use of simple query interfaces allowing only key-based queries. A typical query on such databases is based on the use of protein identifiers and enables the retrieval of one or more proteins. Nevertheless, a lot of biological information is available and is spread on different sources and encoded in different ontologies such as Gene Ontology. The integration of existing PPI databases and biological information may result in richer querying interfaces and successively could enable the development of novel algorithms that may use biological information. The OntoPIN project showed the effectiveness of the introduction of a framework for the ontology-based management and querying of Protein-Protein Interaction Data. The OntoPIN framework first merges PPI data with annotations extracted from existing ontologies (e.g. Gene Ontology) and stores annotated data into a database. Then, a semantic-based query interface enables users to query these data by using biological concepts. OntoPIN allows: (a) to extend existing PPI databases by using ontologies, (b) to enable a key-based querying of annotated data, and (c) to offer a novel query interface based on semantic similarity among annotations.