Structural determinants for activation and block of CFTR-mediated chloride currents by apigenin

Beate Illek, Mike E. Lizarzaburu, Vivien Lee, Michael H. Nantz, Mark J. Kurth, Horst Fischer

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Apigenin (4',5,7-trihydroxyflavone) is an activator of cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl- currents across epithelia at low concentrations and a blocker at high concentrations. We determined the roles of structural components of apigenin for both stimulation and block of Cl- currents across Calu-3 epithelia. The half-maximal binding affinity of apigenin for current stimulation (K(S)) was 9.1 ± 1.3 μM, and the rank-order of molecular structures was 7-hydroxyl > pyrone = 4'-hydroxyl > 5-hydroxyl. Both the 7-hydroxyl and the 4'-hydroxyl served as H-bond acceptors, whereas the 5-hydroxyl was an H-bond donor. The half-maximal binding affinity of apigenin during current block was 74 ± 11 μM. Blocked Cl- currents were structurally determined by 7-hydroxyl = 4'-hydroxyl > pyrone > 5-hydroxyl. Prestimulation of tissues with forskolin significantly affected activation kinetics and binding characteristics. After forskolin stimulation, K(S) was 4.1 ± 0.9 μM, which was structurally determined by pyrone > all hydroxyls > single hydroxyls. In contrast, block of Cl- current by apigenin was not affected by forskolin stimulation. We conclude that apigenin binds to a stimulatory and an inhibitory binding site, which are distinguished by their affinities and the molecular interactions during binding.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume279
Issue number6 48-6
StatePublished - 2000

Fingerprint

Apigenin
Cystic Fibrosis Transmembrane Conductance Regulator
Hydroxyl Radical
Chlorides
Chemical activation
Pyrones
Colforsin
Epithelium
Molecular interactions
Molecular Structure
Molecular structure
Binding Sites

Keywords

  • Binding site
  • Chloride transport
  • Cystic fibrosis transmembrane conductance regulator
  • Epithelia
  • Flavonoids
  • Resveratrol

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology
  • Physiology (medical)

Cite this

Illek, B., Lizarzaburu, M. E., Lee, V., Nantz, M. H., Kurth, M. J., & Fischer, H. (2000). Structural determinants for activation and block of CFTR-mediated chloride currents by apigenin. American Journal of Physiology - Cell Physiology, 279(6 48-6).

Structural determinants for activation and block of CFTR-mediated chloride currents by apigenin. / Illek, Beate; Lizarzaburu, Mike E.; Lee, Vivien; Nantz, Michael H.; Kurth, Mark J.; Fischer, Horst.

In: American Journal of Physiology - Cell Physiology, Vol. 279, No. 6 48-6, 2000.

Research output: Contribution to journalArticle

Illek, B, Lizarzaburu, ME, Lee, V, Nantz, MH, Kurth, MJ & Fischer, H 2000, 'Structural determinants for activation and block of CFTR-mediated chloride currents by apigenin', American Journal of Physiology - Cell Physiology, vol. 279, no. 6 48-6.
Illek, Beate ; Lizarzaburu, Mike E. ; Lee, Vivien ; Nantz, Michael H. ; Kurth, Mark J. ; Fischer, Horst. / Structural determinants for activation and block of CFTR-mediated chloride currents by apigenin. In: American Journal of Physiology - Cell Physiology. 2000 ; Vol. 279, No. 6 48-6.
@article{57349fda66e241d0bc378ad601b51010,
title = "Structural determinants for activation and block of CFTR-mediated chloride currents by apigenin",
abstract = "Apigenin (4',5,7-trihydroxyflavone) is an activator of cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl- currents across epithelia at low concentrations and a blocker at high concentrations. We determined the roles of structural components of apigenin for both stimulation and block of Cl- currents across Calu-3 epithelia. The half-maximal binding affinity of apigenin for current stimulation (K(S)) was 9.1 ± 1.3 μM, and the rank-order of molecular structures was 7-hydroxyl > pyrone = 4'-hydroxyl > 5-hydroxyl. Both the 7-hydroxyl and the 4'-hydroxyl served as H-bond acceptors, whereas the 5-hydroxyl was an H-bond donor. The half-maximal binding affinity of apigenin during current block was 74 ± 11 μM. Blocked Cl- currents were structurally determined by 7-hydroxyl = 4'-hydroxyl > pyrone > 5-hydroxyl. Prestimulation of tissues with forskolin significantly affected activation kinetics and binding characteristics. After forskolin stimulation, K(S) was 4.1 ± 0.9 μM, which was structurally determined by pyrone > all hydroxyls > single hydroxyls. In contrast, block of Cl- current by apigenin was not affected by forskolin stimulation. We conclude that apigenin binds to a stimulatory and an inhibitory binding site, which are distinguished by their affinities and the molecular interactions during binding.",
keywords = "Binding site, Chloride transport, Cystic fibrosis transmembrane conductance regulator, Epithelia, Flavonoids, Resveratrol",
author = "Beate Illek and Lizarzaburu, {Mike E.} and Vivien Lee and Nantz, {Michael H.} and Kurth, {Mark J.} and Horst Fischer",
year = "2000",
language = "English (US)",
volume = "279",
journal = "American Journal of Physiology - Renal Fluid and Electrolyte Physiology",
issn = "1931-857X",
publisher = "American Physiological Society",
number = "6 48-6",

}

TY - JOUR

T1 - Structural determinants for activation and block of CFTR-mediated chloride currents by apigenin

AU - Illek, Beate

AU - Lizarzaburu, Mike E.

AU - Lee, Vivien

AU - Nantz, Michael H.

AU - Kurth, Mark J.

AU - Fischer, Horst

PY - 2000

Y1 - 2000

N2 - Apigenin (4',5,7-trihydroxyflavone) is an activator of cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl- currents across epithelia at low concentrations and a blocker at high concentrations. We determined the roles of structural components of apigenin for both stimulation and block of Cl- currents across Calu-3 epithelia. The half-maximal binding affinity of apigenin for current stimulation (K(S)) was 9.1 ± 1.3 μM, and the rank-order of molecular structures was 7-hydroxyl > pyrone = 4'-hydroxyl > 5-hydroxyl. Both the 7-hydroxyl and the 4'-hydroxyl served as H-bond acceptors, whereas the 5-hydroxyl was an H-bond donor. The half-maximal binding affinity of apigenin during current block was 74 ± 11 μM. Blocked Cl- currents were structurally determined by 7-hydroxyl = 4'-hydroxyl > pyrone > 5-hydroxyl. Prestimulation of tissues with forskolin significantly affected activation kinetics and binding characteristics. After forskolin stimulation, K(S) was 4.1 ± 0.9 μM, which was structurally determined by pyrone > all hydroxyls > single hydroxyls. In contrast, block of Cl- current by apigenin was not affected by forskolin stimulation. We conclude that apigenin binds to a stimulatory and an inhibitory binding site, which are distinguished by their affinities and the molecular interactions during binding.

AB - Apigenin (4',5,7-trihydroxyflavone) is an activator of cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl- currents across epithelia at low concentrations and a blocker at high concentrations. We determined the roles of structural components of apigenin for both stimulation and block of Cl- currents across Calu-3 epithelia. The half-maximal binding affinity of apigenin for current stimulation (K(S)) was 9.1 ± 1.3 μM, and the rank-order of molecular structures was 7-hydroxyl > pyrone = 4'-hydroxyl > 5-hydroxyl. Both the 7-hydroxyl and the 4'-hydroxyl served as H-bond acceptors, whereas the 5-hydroxyl was an H-bond donor. The half-maximal binding affinity of apigenin during current block was 74 ± 11 μM. Blocked Cl- currents were structurally determined by 7-hydroxyl = 4'-hydroxyl > pyrone > 5-hydroxyl. Prestimulation of tissues with forskolin significantly affected activation kinetics and binding characteristics. After forskolin stimulation, K(S) was 4.1 ± 0.9 μM, which was structurally determined by pyrone > all hydroxyls > single hydroxyls. In contrast, block of Cl- current by apigenin was not affected by forskolin stimulation. We conclude that apigenin binds to a stimulatory and an inhibitory binding site, which are distinguished by their affinities and the molecular interactions during binding.

KW - Binding site

KW - Chloride transport

KW - Cystic fibrosis transmembrane conductance regulator

KW - Epithelia

KW - Flavonoids

KW - Resveratrol

UR - http://www.scopus.com/inward/record.url?scp=0033636431&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033636431&partnerID=8YFLogxK

M3 - Article

C2 - 11078699

AN - SCOPUS:0033636431

VL - 279

JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology

JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology

SN - 1931-857X

IS - 6 48-6

ER -