Speaker
Description
Cystic fibrosis (CF) is a hereditary disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein, resulting in the loss of function of this ion channel in the plasma membrane of epithelial cells. CFTR is composed of two transmembrane domains and two intracellular nucleotide-binding domains (NBDs), with the disordered R-domain wedged between them. Phosphorylation of the R-domain is a prerequisite for the opening of the channel, causing it to dissociate from the NBDs. Understanding the mechanism of different mutations requires knowledge of the protein structure. However, with over 350 known CF mutations, it is unfeasible to develop a treatment for all rare mutations. To address this challenge, we propose a general molecular-level intervention to facilitate activation of the channel. By designing a "miniprotein" that binds to the R-domain and inhibits its insertion between the two NBDs, an increase in CFTR activity would become possible. As a first step of this approach, in silico methods were used to model the structure of the complexes formed between the phosphorylation sites of the R-domain and the nucleotide-binding domain 1 (NBD1). Protein structure predictions were performed using AlphaFold-Multimer neural network, which is one of the currently available best methods for predicting the structure of protein complexes. Selected complex structures modelled by AlphaFold-Multimer were studied using molecular dynamics simulations. The models provide information about possible conformations of R-domain and NBD-1 complexes, thus contributing to the selection of target sites for the redesigned “miniproteins”.
Acknowledgements: This research was funded by the ÚNKP-22-2-III-BME-239 New National Excellence Program of the Ministry for Innovation and Technology, NRDIO/NKFIH grant numbers K127961, K137610, and Cystic Fibrosis Foundation (CFF) grant number HEGEDU20I0.
