Terminally misfolded proteins, recognized by chaperones on the endoplasmic reticulum (ER), are transported to depots for ubiquitination and proteasomal degradation by the ER-associated protein degradation (ERAD) pathway. Eeyarestatin 1 is an inhibitor of the ERAD pathway, blocking the degradation of misfolded proteins at a dose of 8 μM.[1] It associates with the p97-associated deubiquitinating complex in cells, preventing deubiquitination of substrates by ataxin-3.[2],[3] Eeyarestatin 1, at 4 μM, interferes with both retrograde and anterograde trafficking of proteins, including certain toxins, and potentially, viruses.[4]

Reference:
[1]. Fiebiger, E., Hirsch, C., Vyas, J.M., et al. Dissection of the dislocation pathway for type I membrane proteins with a new small molecule inhibitor, eeyarestatin. Molecular Biology of the Cell 15, 1635-1646 (2004).
[2]. Wang, Q., Li, L., and Ye, Y. Inhibition of p97-dependent protein degradation by Eeyarestatin I. The Journal of Biological Chemisty 283(12), 7445-7454 (2008).
[3]. Wang, Q., Shinkre, B.A., Lee, J.G., et al. The ERAD inhibitor Eeyarestatin I is a bifunctional compound with a membrane-binding domain and a p97/VCP inhibitory group. PLoS One 5(11), 1-12 (2010).
[4]. Aletrari, M.O., McKibbin, C., Williams, H., et al. Eeyarestatin 1 interferes with both retrograde and anterograde intracellular trafficking pathways. PLoS One 6(7), 1-11 (2011).