The process begins with the lysis of cells to release their intracellular contents. An antibody specific to the protein of interest (the 'bait' protein) is then added to the lysate. This antibody binds to the bait protein, forming an antibody-protein complex. Protein A or G beads, which have a high affinity for the Fc region of antibodies, are then introduced to the mixture to pull down the antibody-protein complex. Any proteins that are bound to the bait protein (the 'prey' proteins) will also be pulled down. After washing away non-specifically bound proteins, the complexes are eluted and analyzed, often by Western blotting or mass spectrometry.
