2. Academic Validation
  3. Channel Gating Regulation by the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) First Cytosolic Loop

Channel Gating Regulation by the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) First Cytosolic Loop

  • J Biol Chem. 2016 Jan 22;291(4):1854-1865. doi: 10.1074/jbc.M115.704809.
Annette Ehrhardt 1,  W Joon Chung 2,  Louise C Pyle 3,  Wei Wang 4,  Krzysztof Nowotarski 4,  Cory M Mulvihill 5,  Mohabir Ramjeesingh 5,  Jeong Hong 6,  Sadanandan E Velu 7,  Hal A Lewis 8,  Shane Atwell 9,  Steve Aller 10,  Christine E Bear 11,  Gergely L Lukacs 12,  Kevin L Kirk 6,  Eric J Sorscher 13
Affiliations

Affiliations

  • 1 From the Gregory Fleming James Cystic Fibrosis Research Center and; the Department of Pediatrics, Emory University, Atlanta, Georgia 30322.
  • 2 From the Gregory Fleming James Cystic Fibrosis Research Center and; Departments of Neurobiology.
  • 3 From the Gregory Fleming James Cystic Fibrosis Research Center and.
  • 4 Cellular, Integrative, and Developmental Biology.
  • 5 the Hospital for Sick Children Research Institute, Toronto M5G 1X8, Canada.
  • 6 From the Gregory Fleming James Cystic Fibrosis Research Center and; Cellular, Integrative, and Developmental Biology.
  • 7 Chemistry, University of Alabama at Birmingham, Birmingham, Alabama 35294.
  • 8 Bristol-Myers Squibb, Princeton, New Jersey 08543.
  • 9 Eli Lilly & Co., San Diego, California 92121.
  • 10 From the Gregory Fleming James Cystic Fibrosis Research Center and; Pharmacology, and.
  • 11 the Hospital for Sick Children Research Institute, Toronto M5G 1X8, Canada,; the Departments of Biochemistry and; Physiology, University of Toronto, Toronto M5G 1X8, Canada, and.
  • 12 the Department of Physiology, McGill University, Montreal H3G 1Y6, Canada.
  • 13 the Department of Pediatrics, Emory University, Atlanta, Georgia 30322,. Electronic address: esorscher@emory.edu.
PMID: 26627831 DOI: 10.1074/jbc.M115.704809
Abstract

In this study, we present data indicating a robust and specific domain interaction between the cystic fibrosis transmembrane conductance regulator (CFTR) first cytosolic loop (CL1) and nucleotide binding domain 1 (NBD1) that allows ion transport to proceed in a regulated fashion. We used co-precipitation and ELISA to establish the molecular contact and showed that binding kinetics were not altered by the common clinical mutation F508del. Both intrinsic ATPase activity and CFTR channel gating were inhibited severely by CL1 peptide, suggesting that NBD1/CL1 binding is a crucial requirement for ATP hydrolysis and channel function. In addition to cystic fibrosis, CFTR dysregulation has been implicated in the pathogenesis of prevalent diseases such as chronic obstructive pulmonary disease, acquired rhinosinusitis, pancreatitis, and lethal secretory diarrhea (e.g. cholera). On the basis of clinical relevance of the CFTR as a therapeutic target, a cell-free drug screen was established to identify modulators of NBD1/CL1 channel activity independent of F508del CFTR and pharmacologic rescue. Our findings support a targetable mechanism of CFTR regulation in which conformational changes in the NBDs cause reorientation of transmembrane domains via interactions with CL1 and result in channel gating.

Keywords

ABC transporter; channel activation; chloride channel; cystic fibrosis; cystic fibrosis transmembrane conductance regulator (CFTR); domain interaction; drug discovery; epithelial cell; pore formation.

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