Conserved Allosteric Hot Spots in the Transmembrane Domains of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Channels and Multidrug Resistance Protein (MRP) Pumps

Abstract

Background: Multidrug resistance proteins (MRPs) and the cystic fibrosis transmembrane conductance regulator (CFTR) are thermodynamically distinct ATP-binding cassette (ABC) transporters. Results: Structural elements that couple ATP binding to channel opening in the CFTR channel also facilitate MRP drug export. Conclusion: MRPs and CFTR share components of a conserved activation mechanism. Significance: Allosteric hot spots suggest mechanistic similarities between thermodynamically distinct ABC transporters.

Long‐range coupling between the extracellular gates and the intracellular ATP binding domains of multidrug resistance protein pumps and cystic fibrosis transmembrane conductance regulator channels

“…Methods used for construction of the Yor1 mutants and analysis of oligomycin sensitivity were previously described (15). For analysis of Ycf1 mutations, the knockout strain (ycf1‐Δ0) from the Research Genetics (Huntsville, AL, USA) Saccharomyces cerevisiae gene deletion collection (23) was transformed by the polyethylene glycol method (24) with plasmids expressing Ycf1p alleles.…”

“…The evolutionary relationship between MRP pumps and the CFTR channel implies that they may use similar mechanisms for coupling ATP binding at the NBD dimer interface to those conformational changes in the TMs that underlie active substrate transport (MRPs) or channel gating (CFTR). Recently we discovered gain of function (GOF) mutations at conserved locations near the cytosolic bases of TMs 6 and 9 in CFTR and in the short MRPs (14, 15). These GOF mutations promoted ATP‐free CFTR channel activity, increased the ATP sensitivity of CFTR gating, and reversed the low ATP sensitivity of a CFTR construct with an NBD2 mutation that disrupts ATP binding.…”

Deletion of Phenylalanine 508 in the First Nucleotide-binding Domain of the Cystic Fibrosis Transmembrane Conductance Regulator Increases Conformational Exchange and Inhibits Dimerization

“…Conversely, VX-809 stabilization of MSD1 is postulated to improve maturation by enhancing stabilizing interactions with MSD2 and NBD1 (62). Gain-of-function mutations, which presumably stabilize an open conformation, have been identified in both MSD1 and MSD2 (63,64). It has also been suggested that low temperature rescue may be an NBD2-related effect (58), which does not occur in the absence of NBD2.…”

Transformative therapies for rare CFTR missense alleles

“…zebrafish, mouse, rat, rabbit, ferret, pig), although each has limitations regarding ease of use or degree to which human disease is recapitulated [35,36]. Finally, yeast phenomic screening has emerged as a means for discovery of gene-gene interaction networks and other features of CFTR class II and III variants [37,38,39], including identification and targeting of novel CFTR modulators in patient-derived epithelia [40]. …”