Design of multi-target peptide modulators for protein chaperone networks

Essential chaperones heat shock protein 70 (Hsp70) and heat shock protein 90 (Hsp90) collaborate in oncoprotein folding. Dual inhibition of these chaperones has shown synergy in preclinical studies but remains challenging to achieve. Using a computational approach, we designed peptides mimicking the predicted unfolding regions of Kinase CDK4, a client protein of both Hsp70 and Hsp90. Peptide Cdk4-2 is shown to simultaneously bind Hsp70, Hsp90, and co-chaperone Cdc37. Cdk4-2 is membrane permeable, inhibits CDK4-mediated retinoblastoma phosphorylation, and induces apoptosis in renal carcinoma cells. Structure-function studies identified a minimal pharmacophore for Hsp70 binding and critical interactions for peptide affinity. These findings demonstrate the feasibility of rationally designing multi-target modulators of chaperone networks. Cdk4-2 is a promising lead for therapeutic development, expanding the molecular space of modulators of cancer-associated multiprotein machineries. While focused on chaperones, the idea behind our strategy is general and immediately transferable to other multiprotein targets and networks.