Calcium binding in the pore of L-type calcium channels modulates high affinity dihydropyridine binding

Blaise Peterson, William A. Catterall

Research output: Contribution to journalArticle

71 Citations (Scopus)

Abstract

The pore-forming α1 subunit of L-type voltage-gated Ca2+ channels contains a Ca2+-binding site that is allosterically coupled to the receptor site for dihydropyridine (DHP) Ca2+ antagonists. Site-directed mutations of conserved Phe and Glu residues in the pore-lining SS1/SS2 segments greatly reduced Ca2+ enhancement of DHP binding. Substitution of Phe-1013 in the α1 subunit from rabbit skeletal muscle (α(1S)) with Gly (F1013G) as in DHP-insensitive Ca2+ channels caused a 4-fold decrease in sensitivity to Ca2+. Mutation of the Ca2+-binding residues Glu-1014 in domain III and Glu-1323 in domain IV to Gln (E1014Q and E1323Q) caused 11- and 35-fold decreases in sensitivity to Ca2+, respectively, as well as decreases in the maximal DHP binding affinities attained at optimal concentrations of Ca2+. DHP binding to the charge-reversal mutation, E1014K, had no sensitivity to Ca2+. Our results demonstrate that high affinity Ca2+ binding to the Glu residues in the SS1/SS2 segments of domains III and IV of α(1s) stabilizes the DHP receptor site in its high affinity state. We propose a three-state model in which the affinity for DHPs is dependent on the presence of 0, 1, or 2 bound Ca2+ ions at sites in the pore.

Original languageEnglish (US)
Pages (from-to)18201-18204
Number of pages4
JournalJournal of Biological Chemistry
Volume270
Issue number31
DOIs
StatePublished - Aug 4 1995

Fingerprint

L-Type Calcium Channels
Calcium
Mutation
Skeletal Muscle
Linings
Binding Sites
Muscle
Ions
Rabbits
Substitution reactions
1,4-dihydropyridine
Electric potential

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

@article{b0ee27c591494e9da814c07eac51a088,
title = "Calcium binding in the pore of L-type calcium channels modulates high affinity dihydropyridine binding",
abstract = "The pore-forming α1 subunit of L-type voltage-gated Ca2+ channels contains a Ca2+-binding site that is allosterically coupled to the receptor site for dihydropyridine (DHP) Ca2+ antagonists. Site-directed mutations of conserved Phe and Glu residues in the pore-lining SS1/SS2 segments greatly reduced Ca2+ enhancement of DHP binding. Substitution of Phe-1013 in the α1 subunit from rabbit skeletal muscle (α(1S)) with Gly (F1013G) as in DHP-insensitive Ca2+ channels caused a 4-fold decrease in sensitivity to Ca2+. Mutation of the Ca2+-binding residues Glu-1014 in domain III and Glu-1323 in domain IV to Gln (E1014Q and E1323Q) caused 11- and 35-fold decreases in sensitivity to Ca2+, respectively, as well as decreases in the maximal DHP binding affinities attained at optimal concentrations of Ca2+. DHP binding to the charge-reversal mutation, E1014K, had no sensitivity to Ca2+. Our results demonstrate that high affinity Ca2+ binding to the Glu residues in the SS1/SS2 segments of domains III and IV of α(1s) stabilizes the DHP receptor site in its high affinity state. We propose a three-state model in which the affinity for DHPs is dependent on the presence of 0, 1, or 2 bound Ca2+ ions at sites in the pore.",
author = "Blaise Peterson and Catterall, {William A.}",
year = "1995",
month = "8",
day = "4",
doi = "10.1074/jbc.270.31.18201",
language = "English (US)",
volume = "270",
pages = "18201--18204",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "31",

}

Calcium binding in the pore of L-type calcium channels modulates high affinity dihydropyridine binding. / Peterson, Blaise; Catterall, William A.

In: Journal of Biological Chemistry, Vol. 270, No. 31, 04.08.1995, p. 18201-18204.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Calcium binding in the pore of L-type calcium channels modulates high affinity dihydropyridine binding

AU - Peterson, Blaise

AU - Catterall, William A.

PY - 1995/8/4

Y1 - 1995/8/4

N2 - The pore-forming α1 subunit of L-type voltage-gated Ca2+ channels contains a Ca2+-binding site that is allosterically coupled to the receptor site for dihydropyridine (DHP) Ca2+ antagonists. Site-directed mutations of conserved Phe and Glu residues in the pore-lining SS1/SS2 segments greatly reduced Ca2+ enhancement of DHP binding. Substitution of Phe-1013 in the α1 subunit from rabbit skeletal muscle (α(1S)) with Gly (F1013G) as in DHP-insensitive Ca2+ channels caused a 4-fold decrease in sensitivity to Ca2+. Mutation of the Ca2+-binding residues Glu-1014 in domain III and Glu-1323 in domain IV to Gln (E1014Q and E1323Q) caused 11- and 35-fold decreases in sensitivity to Ca2+, respectively, as well as decreases in the maximal DHP binding affinities attained at optimal concentrations of Ca2+. DHP binding to the charge-reversal mutation, E1014K, had no sensitivity to Ca2+. Our results demonstrate that high affinity Ca2+ binding to the Glu residues in the SS1/SS2 segments of domains III and IV of α(1s) stabilizes the DHP receptor site in its high affinity state. We propose a three-state model in which the affinity for DHPs is dependent on the presence of 0, 1, or 2 bound Ca2+ ions at sites in the pore.

AB - The pore-forming α1 subunit of L-type voltage-gated Ca2+ channels contains a Ca2+-binding site that is allosterically coupled to the receptor site for dihydropyridine (DHP) Ca2+ antagonists. Site-directed mutations of conserved Phe and Glu residues in the pore-lining SS1/SS2 segments greatly reduced Ca2+ enhancement of DHP binding. Substitution of Phe-1013 in the α1 subunit from rabbit skeletal muscle (α(1S)) with Gly (F1013G) as in DHP-insensitive Ca2+ channels caused a 4-fold decrease in sensitivity to Ca2+. Mutation of the Ca2+-binding residues Glu-1014 in domain III and Glu-1323 in domain IV to Gln (E1014Q and E1323Q) caused 11- and 35-fold decreases in sensitivity to Ca2+, respectively, as well as decreases in the maximal DHP binding affinities attained at optimal concentrations of Ca2+. DHP binding to the charge-reversal mutation, E1014K, had no sensitivity to Ca2+. Our results demonstrate that high affinity Ca2+ binding to the Glu residues in the SS1/SS2 segments of domains III and IV of α(1s) stabilizes the DHP receptor site in its high affinity state. We propose a three-state model in which the affinity for DHPs is dependent on the presence of 0, 1, or 2 bound Ca2+ ions at sites in the pore.

UR - http://www.scopus.com/inward/record.url?scp=0029096732&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029096732&partnerID=8YFLogxK

U2 - 10.1074/jbc.270.31.18201

DO - 10.1074/jbc.270.31.18201

M3 - Article

VL - 270

SP - 18201

EP - 18204

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 31

ER -