A diverse range of systems have recently been developed to promote the degradation of extracellular and membrane protein targets by using bispecific antibodies, conjugates or small molecules to traffic targeted proteins to the lysosome. This article describes and categorizes systems for extracellular targeted protein degradation, including LYTACs, ATACs, AbTACs, PROTABs and KineTACs, and discusses their advantages and the challenges ahead to realizing their therapeutic potential.
