A cell-permeant nanobody-based degrader that induces fetal hemoglobin

Abstract

Proximity-based strategies to degrade proteins have enormous therapeutic potential in medicine, but the technologies are limited to proteins for which small molecule ligands exist. The identification of such ligands for therapeutically relevant but undruggable proteins remains challenging. Herein, we employed yeast surface display of synthetic nanobodies to identify a protein ligand selective for BCL11A, a critical repressor of fetal globin gene transcription. Fusion of the nanobody to a cell-permeant miniature protein and an E3 adaptor creates a degrader that depletes cellular BCL11A in erythroid precursor cells, thereby inducing the expression of fetal hemoglobin, a modifier of clinical severity of sickle cell disease and beta-thalassemia. This work establishes a new paradigm for the targeted degradation of previously intractable proteins using cell-permeant nanobody-based degraders.

Dose-Dependent Nuclear Delivery and Transcriptional Repression with a Cell-Penetrant MeCP2

“…Proteins successfully delivered using ZF5.3 include the self-labeling protein SNAP-tag, 9 the metabolic enzyme argininosuccinate synthetase, 16 the proximity labeling tool APEX2, 9 and a nanobody-based degrader. 17 These proteins differ in molecular weight, stoichiometry, isoelectric point, and the presence of bound cofactors. In all cases evaluated, 9,16 the protein that reached the cytosol was fully intact as judged by Western blot analysis of isolated cytosolic fractions, and the delivery efficiencies were 2−10-fold 9 higher than seen with canonical or cyclic peptides.…”