Biology subjects

Pranke, I.

Publications and source records attributed to Pranke, I..

2 recordsLinked to original sources

bioRxiv2024

Beyond Kaftrio: mechanistic insights to maximize N1303K-CFTR rescue

IntroductionN1303K is the fourth most frequent Cystic Fibrosis (CF) causing mutation. People with CF (pwCF) clinical status can be improved by Elexacaftor(ELX)/Tezacaftor(TEZ)/Ivacaftor (ETI) combotherapy. We investigated the mechanism underlying N1303K-CFTR rescue. MethodsN1303K-CFTR expression and maturation was evaluated by Western Blot in cell lines and Human Nasal Epithelial Primary Cells (HNECs). Cell surface expression was studied by nanoluciferase complementation assay and TurboID proximity labeling. Functional rescue was tested in vitro by YFP-Based Assay and Short Circuit Current. ResultsCorrection by ELX/TEZ increases N1303K-CFTR amounts, but not its maturation in CFTR-expressing HEK and 16HBEge cell lines and in HNECs. In control conditions, N1303K-CFTR is more distributed at the cell surface and significantly more surface partners are identified in the N1303K-CFTR interactome as compared to F508del-CFTR in HEK cells. ELX/TEZ induces a global stabilization of N1303K-CFTR without favoring its plasma membrane relocation in contrast to F508del-CFTR which is redistributed to the membrane. ETI increases N1303K-CFTR activity in HNECs and can be increased by API co-potentiation with a predicted increase in Forced Expiratory Volume in 1 second (ppFEV1) by respectively 13(2)% and 18%(3). This is consistent with a gain in ppFEV1 reported in pwCF carrying the N1303K mutation and additional improvement by API in a patient. ConclusionThese results support the expansion of ETI approval to N1303K mutation but highlight different mechanisms of action than for F508del.

physiology↗

bioRxiv2021

CFTR corrector efficacy is associated with occupancy of distinct binding sites

CFTR misfolding due to cystic fibrosis causing mutations can be corrected with small molecules designated as correctors. VX-809, an investigational corrector compound, is believed to bind CFTR directly to either the first membrane-spanning domain (MSD1) and/or the first nucleotide-binding domain (NBD1). Blind docking onto the 3D structures of these domains, followed by molecular dynamics (MD) simulations, revealed the presence of two potential VX-809 binding sites which, when mutated, abrogated corrector rescue. Mutations altering protein maturation are also shown to be not equally sensitive to the occupancy of the two sites by VX-809, with the most frequent mutation F508del requiring integrity of both sites and allosteric coupling with the F508del region while L206W only requires the integrity of the MSD1 site. A network of charged amino acids in the lasso Lh2 helix and the intracellular loops ICL1 and ICL4 is involved in the allostery between MSD1 and NBD1. Corrector VX-445, which is used in combination in clinics with VX-661, a structurally close analog of VX-809, to fully correct F508del, is also shown to occupy two potential binding sites on MSD1 and NBD1, the latter being shared with VX-809. In conclusion, VX-809 and VX-445 appear to bind different CFTR domains to alleviate specific folding defects. These results provide new insights into therapeutics understanding and may help the development of efficient corrector combinations.

molecular biology↗