Back

Probing the mechanism of Cbl-b inhibition by a small-molecule inhibitor

Kimani, S.; Perveen, S.; Szewczyk, M.; Zeng, H.; Dong, A.; Li, F.; Ghiabi, P.; Li, Y.; Chau, I.; Arrowsmith, C.; Barsyte-Lovejoy, D.; Santhakumar, V.; Vedadi, M.; Halabelian, L.

2023-05-08 immunology
10.1101/2023.05.05.539612 bioRxiv
Show abstract

Cbl-b is a RING-type E3 ubiquitin ligase that is expressed in several immune cell lineages, where it negatively regulates the activity of immune cells. Cbl-b has specifically been identified as an attractive target for cancer immunotherapy due to its role in promoting an immunosuppressive tumor environment, and Nx-1607, is in phase I clinical trials for advanced solid tumor malignancies. Using a suite of biophysical and cellular assays, we confirmed potent binding of C7683 (an analogue of Nx-1607) to the full-length Cbl-b and its N-terminal fragment containing the TKBD-LHR-RING domains. To further elucidate its mechanism of inhibition, we determined the co-crystal structure of Cbl-b with C7683, revealing compound interaction with both the TKBD and LHR, but not the ring domain. Here, we provide structural insights into a novel mechanism of Cbl-b inhibition by a small-molecule inhibitor that locks the protein in an inactive conformation by acting as an intramolecular glue.

Matching journals

The top 6 journals account for 50% of the predicted probability mass.

50% of probability mass above

"Similar papers" are the closest papers from that journal in the model's embedding space. They show what the match is built on, but the ranking comes mostly from a classifier over the whole training set, not from these examples alone.