Create a graphical abstract for a PROTAC targeted protein degradation paper: PROTAC bifunctional molecule design with target protein ligand (warhead), flexible PEG linker, and E3 ubiquitin ligase recruiter (CRBN/VHL binder). Show ternary complex formation (target-PROTAC-E3), induced proximity, K48-linked polyubiquitination by E2 conjugating enzyme, proteasomal degradation of target protein. Compare with traditional occupancy-driven inhibition: catalytic vs stoichiometric mechanism, DC50 and Dmax parameters.