Molecular dynamics and functional characterization of I37R-CFTR lasso mutation provide insights into channel gating activity
Sharon L. Wong,
Nikhil T. Awatade,
Miro A. Astore,
Katelin M. Allan,
Michael J. Carnell,
Iveta Slapetova,
Po-chia Chen,
Alexander Capraro,
Laura K. Fawcett,
Renee M. Whan,
Renate Griffith,
Chee Y. Ooi,
Serdar Kuyucak,
Adam Jaffe,
Shafagh A. Waters
Affiliations
Sharon L. Wong
School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), UNSW Sydney, Sydney, Australia
Nikhil T. Awatade
School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), UNSW Sydney, Sydney, Australia
Miro A. Astore
School of Physics, University of Sydney, Sydney, Australia
Katelin M. Allan
School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), UNSW Sydney, Sydney, Australia
Michael J. Carnell
Katharina Gaus Light Microscopy Facility, Mark Wainwright Analytical Centre, UNSW Sydney, Sydney, Australia
Iveta Slapetova
Katharina Gaus Light Microscopy Facility, Mark Wainwright Analytical Centre, UNSW Sydney, Sydney, Australia
Po-chia Chen
School of Physics, University of Sydney, Sydney, Australia
Alexander Capraro
School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), UNSW Sydney, Sydney, Australia
Laura K. Fawcett
School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), UNSW Sydney, Sydney, Australia; Department of Respiratory Medicine, Sydney Children's Hospital, Randwick, Australia
Renee M. Whan
Katharina Gaus Light Microscopy Facility, Mark Wainwright Analytical Centre, UNSW Sydney, Sydney, Australia
Renate Griffith
School of Chemistry, UNSW Sydney, Sydney, Australia
Chee Y. Ooi
School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), UNSW Sydney, Sydney, Australia; Department of Gastroenterology, Sydney Children's Hospital, Randwick, Australia
Serdar Kuyucak
School of Physics, University of Sydney, Sydney, Australia
Adam Jaffe
School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), UNSW Sydney, Sydney, Australia; Department of Respiratory Medicine, Sydney Children's Hospital, Randwick, Australia
Shafagh A. Waters
School of Women's and Children's Health, Faculty of Medicine and Health, UNSW Sydney, Sydney, Australia; Molecular and Integrative Cystic Fibrosis Research Centre (miCF_RC), UNSW Sydney, Sydney, Australia; Department of Respiratory Medicine, Sydney Children's Hospital, Randwick, Australia; Corresponding author
Summary: Characterization of I37R, a mutation located in the lasso motif of the CFTR chloride channel, was conducted by theratyping several CFTR modulators from both potentiator and corrector classes. Intestinal current measurements in rectal biopsies, forskolin-induced swelling (FIS) in intestinal organoids, and short circuit current measurements in organoid-derived monolayers from an individual with I37R/F508del CFTR genotype demonstrated that the I37R-CFTR results in a residual function defect amenable to treatment with potentiators and type III, but not type I, correctors. Molecular dynamics of I37R using an extended model of the phosphorylated, ATP-bound human CFTR identified an altered lasso motif conformation which results in an unfavorable strengthening of the interactions between the lasso motif, the regulatory (R) domain, and the transmembrane domain 2 (TMD2). Structural and functional characterization of the I37R-CFTR mutation increases understanding of CFTR channel regulation and provides a potential pathway to expand drug access to CF patients with ultra-rare genotypes.
