How do I detect ER stress?

Excessive accumulation of misfolded proteins in the endoplasmic reticulum (ER) is the main cause of ER stress.

ER stress is detected using Thioflavin T (ThT). This is a relatively new method that is being used to detect endoplasmic reticulum (ER) stress in live cells.

Thioflavin T is a tiny molecule that exhibits enhanced fluorescence on binding to protein aggregates. The enhanced ThT-fluorescence correlates directly with proven indicators of UPR (unfolded protein response) activation. Thioflavin T enables researchers to detect ER stress induced by a variety of conditions and compounds within 20 minutes of applying the ER-stress inducing agent.

ER stress can also be detected indirectly by measuring the levels of specific UPR factors. Commonly measured indicators of UPR activation include: phosphorylated PERK, phosphorylated eIF2α, Gadd153/CHOP, ATF4, Grp78/BiP, Grp94, calreticulin, and protein disulphide isomerase (PDI). These are usually detected by immunoblot or immunohistochemistry.