Integration between the three types of sequence-related databases (nucleic acid sequences, protein sequences and protein tertiary structures) as well as with specialized data collections is important to our users. UniProtKB is currently cross-referenced with more than 10 million links to 114 different databases with regular update cycles. Table 1 lists the 17 new and diverse databases added in the past year. Database cross-references are stored in the DR (Database Reference) lines and allow access to related information in other databases. This extensive network of cross-references allows UniProt to act as a focal point of biomolecular database interconnectivity. All cross-referenced databases are documented at http://www.uniprot.org/docs/dbxref and if appropriate are included in the UniProt ID mapping tool at http://www.uniprot.org/help/mapping with the file for download at ftp://ftp.uniprot.org/pub/databases/uniprot/current_release/knowledgebase/idmapping. Database nameDatabase informationBgeedataBase for Gene Expression EvolutionCTDComparative Toxicogenomics DatabaseCAZyCarbohydrate-Active enzymesGeneCardsGeneCards: human genes, protein and diseasesIPIInternational Protein IndexNextBioNextBio gene-centric data for human, mouse, rat, fly, worm and yeastOMAIdentification of Orthologs from Complete Genome DataPathway_ Interaction_DBNCI-Nature Pathway Interaction DatabasePMAP_CutDBCutDB - Proteolytic event databasePRIDEPRoteomics IDEntifications databaseSTRINGSTRING: functional protein association networksTCDBTransport Classification DatabaseUCSCUniversity of California Santa Cruz Genome BrowserXenBaseXenopus laevis and tropicalis biology and genomics resource
