FIGURE 1.

Protein degradation pathways. Degradation of specific proteins can be divided into two categories: proteasome pathway and lysosome‐autophagy pathway. The former could be further classified into the ubiquitin‐proteasome pathway and midnolin‐proteasome pathway, which was a novel ubiquitination‐independent protein degradation pathway discovered by Gu et al. ¹ The latter could be through microautophagy, macroautophagy, and chaperone‐mediated autophagy.