Figure 5From: Framework for a Protein OntologyA PRO example using nodes and relationships illustrated by Smad2 protein. Not all possibilities are indicated. Cross-references to source of information (in curly braces) and description of sequence forms (in parentheses) are given for clarity. The symbols preceding each PRO accession are as follows: $: root; >: has_part (for domains) or derives_from (for proteins); <: variant_of.Back to article page