Updated project metadata. Updated publication reference for PubMed record(s): 26344197. Updated publication reference for PubMed record(s): 26870755, 26344197. By combining extensive biochemical fractionation with quantitative mass spectrometry, we directly examined the composition of soluble multiprotein complexes among diverse animal models. The project has been jointly supervised by Andrew Emili and Edward M. Marcotte. Project website: http://metazoa.med.utoronto.ca