text: user208: How can I find ligands of receptors (or vice versa)?
  For example, I want to find the receptors of IL-8 (CXCL8).
  
  user404: Have you tried STRING? 
  It's a publicly available protein-protein interaction database, so it won't be a complete picture. 
  Ingenuity Pathways Analysis (IPA) is really nice but is a paid service. Ask your institution if they have a license for one. 
  
  user208: CellPhoneDB is a publicly available repository of curated receptors, ligands and their interactions.
  The interactions can be searched or downloaded.
  
original_text: 208: <p>How can I find ligands of receptors (or <em>vice versa</em>)?</p>
  
  <p>For example, I want to find the receptors of IL-8 (CXCL8).</p>
   404: <p>Have you tried <a href="https://string-db.org/cgi/input.pl?sessionId=QLEnNyQMCbBE&amp;input_page_show_search=on" rel="nofollow noreferrer">STRING</a>? </p>
  
  <p>It's a publicly available protein-protein interaction database, so it won't be a complete picture. </p>
  
  <p><a href="https://www.qiagenbioinformatics.com/products/ingenuity-pathway-analysis/" rel="nofollow noreferrer">Ingenuity Pathways Analysis (IPA)</a> is really nice but is a paid service. Ask your institution if they have a license for one. </p>
   208: <p><a href="https://www.cellphonedb.org" rel="nofollow noreferrer">CellPhoneDB</a> is a publicly available repository of <em>curated</em> receptors, ligands and their interactions.</p>
  
  <p>The interactions can be searched or downloaded.</p>
  