From GO Public
Mapping other classification systems to GO
Why are Interpro2go mappings not updated with GOA releases?
GOA is updated in accordance with the latest data released by its core databases (SWISS-PROT, TrEMBL, InterPro, Ensembl) as well as mappings of SWISS-PROT Keywords, InterPro and Enzyme Commission (EC) terms to GO. Each of GOA's core databases produces its own releases; for example, InterPro has dependencies on the member databases of InterPro. InterPro2GO is updated at regular intervals but not always in keeping with monthly schedule of GOA releases.
What are mappings?
The files contain concepts from systems external to GO e.g. Enzyme Commission numbers, SWISS-PROT keywords and TIGR roles, indexed to equivalent GO terms. The mappings are typically made manually; details can be found in the file header. See the Mappings to GO for files available.