As of the present time, the UPR pathway has been identified in A. nidulans, T. reesei and A. niger , but UPR regulation under solid-state culture is still unknown.

• 内质网中蛋白质的未折叠或错误折叠是蛋白分泌途径中的主要瓶颈，因而对蛋白分泌途径的研究热点集中于未折叠蛋白反应（UPR）。