This disclosure relates to methods for assessing and quantifying ER stress. More particularly, the methods disclosed herein are based on assessing phosphorylation of IRE1a and PERK using a polyacrylamide gel containing a phosphate-binding moiety. The detection method disclosed herein allows for quantitative assessment of the level of stress in the ER and UPR activation, which provides basis for diagnosing ER stress disorders and for therapeutic drug screening.
