title: Interplay between inhibitory ferric and stimulatory curcumin regulates phosphorylation-dependent human cystic fibrosis transmembrane conductance regulator and ΔF508 activity.
abstract: Curcumin potentiates cystic fibrosis transmembrane conductance regulator (CFTR) activation in an ATP-independent but phosphorylation-dependent manner. The underlying molecular mechanisms are unclear. Here, HEK-293T cells cultured in an Fe(3+)-containing medium were transiently transfected with CFTR constructs, and the role of the inhibitory Fe(3+) bridge between intracellular loop 3 and the regulatory domain of CFTR in this pathway was investigated. The results showed that ethylenediaminetetraacetic acid (EDTA) stimulated phosphorylation-dependent CFTR activation and the stimulation was suppressed by the deletion of the regulatory domain or the insertion of a C832A mutation that removes the Fe(3+)-binding interface. Furthermore, curcumin potentiation of CFTR was significantly weakened not only by Fe(3+)-insensitive mutations at the interface between the regulatory domain and intracellular loop 3 but also by N-ethylmaleimide or EDTA pretreatment that removes Fe(3+). More importantly, potentiation of CFTR was completely suppressed by sufficient Fe(3+). Finally, the insertion of Fe(3+)-insensitive H950R/S768R increased the curcumin-independent activity of ΔF508 but weakened its curcumin potentiation. Thus, Fe(3+) homeostasis in epithelia may play a critical role in regulating CFTR activity, and targeting Fe(3+)-chelating potentiators may direct new therapies for cystic fibrosis.
authors: Department of Physiology and Biophysics and Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham School of Medicine , Birmingham, Alabama 35294, United States.
authors: Guangyu
authors: G
authors: Wang
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002614:Chelating Agents / Q000494:pharmacology; D003474:Curcumin / Q000494:pharmacology*; D003550:Cystic Fibrosis / Q000188:drug therapy / Q000235:genetics; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000819:agonists* / Q000037:antagonists & inhibitors* / Q000235:genetics; D004492:Edetic Acid / Q000494:pharmacology; D005290:Ferric Compounds / Q000378:metabolism / Q000494:pharmacology*; D057809:HEK293 Cells; D006801:Humans; D009154:Mutation; D010766:Phosphorylation / Q000187:drug effects
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D002614:Chelating Agents; D005290:Ferric Compounds; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D004492:Edetic Acid; D003474:Curcumin