Glycoprotein quality control-related proteins effectively inhibit fibrillation of amyloid beta 1-42.

Formation of amyloid beta (Aβ) aggregates is a risk factor for Alzheimer's disease. Accumulation of Aβ aggregates on the cell surface causes oxidative stress, and ultimately results in cell death. Consequently, inhibition of aggregate formation is predicted to be beneficial. Recently, translocation of glycoprotein quality control-related (GPQC) proteins such as chaperones and protein disulfide-isomerase (PDI) family members was reported under oxidative stress conditions. Therefore, it is possible that GPQC proteins contact Aβ peptides on the cell membrane during stress conditions. Here, we examined the effect of ER resident proteins on Aβ aggregation. Our results show that minimal expression of GPQC proteins enables Aβ to effectively avoid aggregation. Moreover, further analyses show that Aβ structure remains in the monomer state in the presence of ER proteins. Thus, our findings show that GPQC proteins have strong affinity for Aβ monomers, and suggests that the interaction between them repeatedly associates and dissociates in a short period of time.