Co-immunoprecipitation is an invaluable technique in evaluating native protein–protein interactions in vitro and in vivo. However, it can be difficult to detect interactions of a very transient nature, particularly interactions with phosphatases and kinases. The evaluation of the phosphorylation status of c-Myc can also be challenging with the current commercially available phosphorylation sensitive antibodies. Here, we describe two protocols: one for the co-immunoprecipitation of endogenous c-Myc to detect protein–protein interactions and second, for the immunoprecipitation of endogenous c-Myc to probe for phosphorylation status.
