A screenshot of the query page in HPRD. A user can search multiple annotation fields to retrieve protein entries based on protein name, molecular function, PTMs, cellular component, domains, motifs, tissue expression, length, molecular weight and diseases. The query system allows Boolean searches and the query terms are provided as pop-up lists for query fields other than protein name and diseases. Wild card searches using * are permitted by the query engine. Querying multiple search fields is processed as an ‘AND’ type of query by default. For example, a search for an adapter molecule, phosphorylation, nucleus, SH3 domain and thymus, as shown in the figure will retrieve a single entry for the Fyn binding protein, FYB, which satisfies all these parameters.