Fig. 8.

Effect of KCNE2 on hERG turnover rate and the impact of S98A mutation. Details of pulse-chase experiments in COS-7 cells and data interpretation are provided in text. A: quantifying hERG turnover rates when expressed alone or coexpressed with KCNE2. A, top: autoradiographs (³⁵S hERG) and IB of immunoprecipitates from WCL using hERG Ab (IP: hERG) after chase times marked on top. A, bottom: time courses of decay of hERG ³⁵S-radioactivity in immunoprecipitates. Data are normalized by the 0 chase time data point of hERG expressed alone and fit with a single exponential function to estimate the time constants (τ) of hERG turnover (inset, *P < 0.05). B: S98A negates the KCNE2 effect of accelerating hERG turnover. Shown are ³⁵S-autoradiographs of hERG immunoprecipitates from WCL prepared from COS-7 cells expressing the cDNA(s) listed on the left and subjected to pulse-chase experiments using the same procedures as in A. The chase times are listed on top.