Emerging Concepts of Targeted Protein Degrader Technologies via Lysosomal Pathways

Targeted protein degradation (TPD) has emerged as a revolutionary strategy for modulating protein function, offering a promising alternative to traditional small-molecule inhibitors. The distinctive mechanism of action in TPD has previously allowed researchers to target undruggable proteins, broadening the scope of "druggable" properties and expanding the scope of therapeutic possibilities. As the field of TPD advances, several alternative strategies to proteolysis-targeting chimeras (PROTACs) have emerged, which do not rely on the E3 ubiquitin ligase recruitment mechanism, expending the scope of TPD. Recently, several new technologies have emerged for TPD of extracellular and membrane proteins. While encouraging progress has been made in this field, the application of these technologies remains in its early stages. In this review, we explore the therapeutic potential of current key emerging lysosome-mediated TPD approaches by summarizing key discoveries and address the challenges associated with degrading extracellular and membrane protein targets. We also outline the chemical structure, activity, and pharmaceutical properties of each degrader, as well as the development of chemical probes for perturbing autophagy pathways.