Digly analysis of human Kv7.1 transfected in HEK293 cells.

Polyubiquitin chain diversity generates a ‘ubiquitin code’ that universally regulates protein functional expression but functions of polyubiquitin diversity are mostly unknown. Using digly mass spectrometry, we have evaluated the basal polyubiquitin diversity on Kv7.1 ion channels expressed with a C-terminal YFP tag in HEK293 cells. Further, we co-expressed the E3 ligases NEDD4L and ITCH which downregulate Kv7.1 channels and investigated the change in polyubiquitin linkages on the channel.