# Transgenic expression of endoplasmic reticulum proteins in C. elegans neurons is prone to causing ER stress

## TL;DR

Expressing ER proteins with a fluorescent tag in C. elegans neurons can cause subtle ER stress that becomes noticeable only when ERAD is impaired.

## Contribution

The study reveals that ER stress from transgenic ER markers is subtle and detectable only when ERAD is disrupted.

## Key findings

- GFP-tagged ER proteins cause low-level ER stress in C. elegans neurons.
- ER stress is detectable only when the ERAD pathway is compromised.
- This suggests ER stress may contribute to transgenic marker-related phenotypes.

## Abstract

In studying the endomembrane system, organelle-specific markers tagged with fluorescent proteins are used to visualize individual organelles. However, whether the expression of organelle marker perturbs the organelle's biology is not always apparent. We report that expression of a GFP-tagged Endoplasmic Reticulum (ER) protein causes low levels of ER stress that are challenging to detect in control animals. This stress is revealed only once the ER-associated degradation (ERAD) pathway is compromised. Our results highlight the vulnerability of the ER and suggest that the possible contribution of ER stress to phenotypes obtained with transgenic markers should be considered when interpreting the phenotypes.