Resource	URL	Ref.
Functional annotations
Gene Ontology	http://geneontology.org/	167
UniProt	https://www.uniprot.org/	168
KEGG	https://www.genome.jp/kegg/	169
Orthologues
OrthoDB	https://www.orthodb.org/	170
gProfiler	https://biit.cs.ut.ee/gprofiler/orth	171
Databases of protein–protein interactions
The Human Protein Atlas	https://www.proteinatlas.org/	172
STRING	https://string-db.org/	173
BioGRID	https://thebiogrid.org/	174
PICKLE	http://www.pickle.gr	175
APID	http://apid.dep.usal.es	176
IntAct	https://www.ebi.ac.uk/intact	177
Pathway Commons	http://www.pathwaycommons.org/	178
Ligand–receptor interactions
IUPHAR/BPS Guide to Pharmacology	https://www.guidetopharmacology.org/	179
Resources for cell–cell interactions from the Bader laboratory	http://baderlab.org/CellCellInteractions	32
Compendium of ligand–receptor pairs in the literature	https://github.com/LewisLabUCSD/Ligand-Receptor-Pairs	10.1038/s41576-020-00292-x