Co-Immunoprecipitation (Co-IP) is the method used to pull down protein partners of a protein of interest using an antibody that specifically binds to this specific protein in order to test protein-protein interaction. “Pulled down” proteins can be analyzed by western blot for suspected protein partner, or by Mass spectrometry for high throughput protein partner identification. The advantage of this technique is that endogenous protein partners can be identified from cell lines that naturally express these factors.

This protocol is optimized for hard-to-extract nuclear proteins, e.g., that stick to the nuclei inclusion bodies / nucleosome complexes such as TLX1 and TLX3 (Dadi et al., 2012). Most often, these factors are not soluble when using classical protein extraction methods. We used to add nucleases in order to increase solubilization of protein complexes trapped within inclusion bodies; though the efficacy varies depending on the given protein and therefore has to be empirically determined.

Biochemistry (生物化学)

Protein (蛋白)

ImmunoPrecipitation (免疫沉淀)