Using sequential immunoprecipitation and mass spectrometry to identify methylation of NF-κB.

Posttranslational modifications have long been known to play an essential role in the regulation of NF-κB activity. In the past few years, in addition to more traditional modifications such as phosphorylation, the p65 subunit of NF-κB has been found to be methylated at multiple sites. Here, we describe procedures for using immunoprecipitation and mass spectrometry to identify the methylation sites of p65.