Figure 1.

Illustration of PRO categories and relation to external resources. Categories (aka metaclasses) are listed along the top, with example terms for IRF5 (interferon regulatory factor 5) shown directly below. Circles denote protein terms, whereas squares denote protein complex terms. For each, blue indicates terms that are defined in an organism-agnostic way; green indicates terms that are organism-specific. Solid lines show is_a relationships and broken lines show has_component relationships (though the complexes in this example have components in the modification category, this need not be the case). Filled circles and filled squares indicate how UniProtKB and GO, respectively, fit into the hierarchy. Not all terms and relationships are shown. IRF, interferon regulatory factor; Phos, phosphorylated; m, mouse; h, human; iso, isoform; BMv, bone marrow variant.