Discovery and characterization of peptide inhibitors for calcium and integrin binding protein 1.
PUHL, Ana Cristina; BOGART, Jonathan W.; HABERMAN, Victoria A.; LARSON, Jacob E.; GODOY, Andre Schutzer de; NORRIS-DROUIN, Jacqueline L.; CHOLENSKY, Stephanie H.; LEISNER, Tina M.; FRYE, Stephen V.; PARISE, Leslie V.; BOWERS, Albert A.; PEARCE, Kenneth H.
PUHL, Ana Cristina; BOGART, Jonathan W.; HABERMAN, Victoria A.; LARSON, Jacob E.; GODOY, Andre Schutzer de; NORRIS-DROUIN, Jacqueline L.; CHOLENSKY, Stephanie H.; LEISNER, Tina M.; FRYE, Stephen V.; PARISE, Leslie V.; BOWERS, Albert A.; PEARCE, Kenneth H.
Abstract: Calcium and integrin binding protein 1 (CIB1) is an EF-hand-containing, small intracellular protein that has recently been implicated in cancer cell survival and proliferation. In particular, CIB1 depletion significantly impairs tumor growth in triple-negative breast cancer (TNBC). Thus, CIB1 is a potentially attractive target for cancer chemotherapy that has yet to be validated by a chemical probe. To produce a probe molecule to the CIB1 helix 10 (H10) pocket and demonstrate that it is a viable target for molecular intervention, we employed random peptide phage display to screen and select CIB1-binding peptides. The top peptide sequence selected, UNC10245092, was produced synthetically, and binding to CIB1 was confirmed by isothermal titration calorimetry (ITC) and a time-resolved fluorescence resonance energy transfer (TR-FRET) assay. Both assays showed that the peptide bound to CIB1 with low nanomolar affinity. CIB1 was cocrystallized with UNC10245092, and the 2.1 Å resolution structure revealed that the peptide binds as an a-helix in the H10 pocket, displacing the CIB1 C-terminal H10 helix and causing conformational changes in H7 and H8. UNC10245092 was further derivatized with a C-terminal Tat-derived cell penetrating peptide (CPP) to demonstrate its effects on TNBC cells in culture, which are consistent with results of CIB1 depletion. These studies provide a first-in-class chemical tool for CIB1 inhibition in cell culture and validate the CIB1 H10 pocket for future probe and drug discovery efforts.
@article={003000702,author = {PUHL, Ana Cristina; BOGART, Jonathan W.; HABERMAN, Victoria A.; LARSON, Jacob E.; GODOY, Andre Schutzer de; NORRIS-DROUIN, Jacqueline L.; CHOLENSKY, Stephanie H.; LEISNER, Tina M.; FRYE, Stephen V.; PARISE, Leslie V.; BOWERS, Albert A.; PEARCE, Kenneth H.},title={Discovery and characterization of peptide inhibitors for calcium and integrin binding protein 1},journal={ACS Chemical Biology},note={v. 15, n. 6, p. 1505-1516},year={2020}}