NIH grant: 5R01GM080646-09
PRO provides an ontological representation of protein-related entities by explicitly defining them and showing the relationships between them. Each PRO term represents a distinct class of entities (including specific modified forms, orthologous isoforms, and protein complexes) ranging from the taxon-neutral to the taxon-specific (e.g. the entity representing all protein products of the human SMAD2 gene is described in PR:Q15796; one particular human SMAD2 protein form, phosphorylated on the last two serines of a conserved C-terminal SSxS motif is defined by PR:000025934). Current release: 49.0.
PRO Wiki
PRO tutorial
PRO Publications
PRO Statistics
Browse PRO

Example: methylated (sample output)
Retrieve a PRO entry (enter a PRO ID):

Example: PR:000025934 (sample output)
Search PRO (enter text or ID):

Example: smad (sample output)
Annotation: RACE-PRO PRO tracker

PRO encompasses three sub-ontologies: proteins based on evolutionary relatedness (ProEvo); protein forms produced from a given gene locus (ProForm); and protein-containing complexes (ProComp).
(Explanation of the figure)