Orthograde dihydropyridine receptor signal regulates ryanodine receptor passive leak

José Miguel Eltit, Hongli Li, Christopher W. Ward, Tadeusz Molinski, Isaac N Pessah, Paul D. Allen, José R. Lopez

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The skeletal muscle dihydropyridine receptor (DHPR) and ryanodine receptor (RyR1) are known to engage a form of conformation coupling essential for muscle contraction in response to depolarization, referred to as excitation-contraction coupling. Here we use WT and CaV1.1 null (dysgenic) myotubes to provide evidence for an unexplored RyR1-DHPR interaction that regulates the transition of the RyR1 between gating and leak states. Using double-barreled Ca2+-selective microelectrodes, we demonstrate that the lack of CaV1.1 expression was associated with an increased myoplasmic resting [Ca2+] ([Ca2+]rest), increased resting sarcolemmal Ca2+ entry, and decreased sarcoplasmic reticulum (SR) Ca2+ loading. Pharmacological control of the RyR1 leak state, using bastadin 5, reverted the three parameters to WT levels. The fact that Ca 2+ sparks are not more frequent in dysgenic than in WT myotubes adds support to the hypothesis that the leak state is a conformation distinct from gating RyR1s. We conclude from these data that this orthograde DHPR-to-RyR1 signal inhibits the transition of gated RyR1s into the leak state. Further, it suggests that the DHPR-uncoupled RyR1 population in WT muscle has a higher propensity to be in the leak conformation. RyR1 leak functions are to keep [Ca2+]rest and the SR Ca2+ content in the physiological range and thus maintain normal intracellular Ca2+ homeostasis.

Original languageEnglish (US)
Pages (from-to)7046-7051
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number17
DOIs
StatePublished - Apr 26 2011

Fingerprint

L-Type Calcium Channels
Ryanodine Receptor Calcium Release Channel
Skeletal Muscle Fibers
Sarcoplasmic Reticulum
Excitation Contraction Coupling
Microelectrodes
Muscle Contraction
Skeletal Muscle
Homeostasis
Pharmacology
Muscles

Keywords

  • L-type calcium channel
  • Resting calcium

ASJC Scopus subject areas

  • General

Cite this

Orthograde dihydropyridine receptor signal regulates ryanodine receptor passive leak. / Eltit, José Miguel; Li, Hongli; Ward, Christopher W.; Molinski, Tadeusz; Pessah, Isaac N; Allen, Paul D.; Lopez, José R.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 108, No. 17, 26.04.2011, p. 7046-7051.

Research output: Contribution to journalArticle

Eltit, José Miguel ; Li, Hongli ; Ward, Christopher W. ; Molinski, Tadeusz ; Pessah, Isaac N ; Allen, Paul D. ; Lopez, José R. / Orthograde dihydropyridine receptor signal regulates ryanodine receptor passive leak. In: Proceedings of the National Academy of Sciences of the United States of America. 2011 ; Vol. 108, No. 17. pp. 7046-7051.
@article{c591ca170fe047e0b394292b7908450b,
title = "Orthograde dihydropyridine receptor signal regulates ryanodine receptor passive leak",
abstract = "The skeletal muscle dihydropyridine receptor (DHPR) and ryanodine receptor (RyR1) are known to engage a form of conformation coupling essential for muscle contraction in response to depolarization, referred to as excitation-contraction coupling. Here we use WT and CaV1.1 null (dysgenic) myotubes to provide evidence for an unexplored RyR1-DHPR interaction that regulates the transition of the RyR1 between gating and leak states. Using double-barreled Ca2+-selective microelectrodes, we demonstrate that the lack of CaV1.1 expression was associated with an increased myoplasmic resting [Ca2+] ([Ca2+]rest), increased resting sarcolemmal Ca2+ entry, and decreased sarcoplasmic reticulum (SR) Ca2+ loading. Pharmacological control of the RyR1 leak state, using bastadin 5, reverted the three parameters to WT levels. The fact that Ca 2+ sparks are not more frequent in dysgenic than in WT myotubes adds support to the hypothesis that the leak state is a conformation distinct from gating RyR1s. We conclude from these data that this orthograde DHPR-to-RyR1 signal inhibits the transition of gated RyR1s into the leak state. Further, it suggests that the DHPR-uncoupled RyR1 population in WT muscle has a higher propensity to be in the leak conformation. RyR1 leak functions are to keep [Ca2+]rest and the SR Ca2+ content in the physiological range and thus maintain normal intracellular Ca2+ homeostasis.",
keywords = "L-type calcium channel, Resting calcium",
author = "Eltit, {Jos{\'e} Miguel} and Hongli Li and Ward, {Christopher W.} and Tadeusz Molinski and Pessah, {Isaac N} and Allen, {Paul D.} and Lopez, {Jos{\'e} R.}",
year = "2011",
month = "4",
day = "26",
doi = "10.1073/pnas.1018380108",
language = "English (US)",
volume = "108",
pages = "7046--7051",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "17",

}

TY - JOUR

T1 - Orthograde dihydropyridine receptor signal regulates ryanodine receptor passive leak

AU - Eltit, José Miguel

AU - Li, Hongli

AU - Ward, Christopher W.

AU - Molinski, Tadeusz

AU - Pessah, Isaac N

AU - Allen, Paul D.

AU - Lopez, José R.

PY - 2011/4/26

Y1 - 2011/4/26

N2 - The skeletal muscle dihydropyridine receptor (DHPR) and ryanodine receptor (RyR1) are known to engage a form of conformation coupling essential for muscle contraction in response to depolarization, referred to as excitation-contraction coupling. Here we use WT and CaV1.1 null (dysgenic) myotubes to provide evidence for an unexplored RyR1-DHPR interaction that regulates the transition of the RyR1 between gating and leak states. Using double-barreled Ca2+-selective microelectrodes, we demonstrate that the lack of CaV1.1 expression was associated with an increased myoplasmic resting [Ca2+] ([Ca2+]rest), increased resting sarcolemmal Ca2+ entry, and decreased sarcoplasmic reticulum (SR) Ca2+ loading. Pharmacological control of the RyR1 leak state, using bastadin 5, reverted the three parameters to WT levels. The fact that Ca 2+ sparks are not more frequent in dysgenic than in WT myotubes adds support to the hypothesis that the leak state is a conformation distinct from gating RyR1s. We conclude from these data that this orthograde DHPR-to-RyR1 signal inhibits the transition of gated RyR1s into the leak state. Further, it suggests that the DHPR-uncoupled RyR1 population in WT muscle has a higher propensity to be in the leak conformation. RyR1 leak functions are to keep [Ca2+]rest and the SR Ca2+ content in the physiological range and thus maintain normal intracellular Ca2+ homeostasis.

AB - The skeletal muscle dihydropyridine receptor (DHPR) and ryanodine receptor (RyR1) are known to engage a form of conformation coupling essential for muscle contraction in response to depolarization, referred to as excitation-contraction coupling. Here we use WT and CaV1.1 null (dysgenic) myotubes to provide evidence for an unexplored RyR1-DHPR interaction that regulates the transition of the RyR1 between gating and leak states. Using double-barreled Ca2+-selective microelectrodes, we demonstrate that the lack of CaV1.1 expression was associated with an increased myoplasmic resting [Ca2+] ([Ca2+]rest), increased resting sarcolemmal Ca2+ entry, and decreased sarcoplasmic reticulum (SR) Ca2+ loading. Pharmacological control of the RyR1 leak state, using bastadin 5, reverted the three parameters to WT levels. The fact that Ca 2+ sparks are not more frequent in dysgenic than in WT myotubes adds support to the hypothesis that the leak state is a conformation distinct from gating RyR1s. We conclude from these data that this orthograde DHPR-to-RyR1 signal inhibits the transition of gated RyR1s into the leak state. Further, it suggests that the DHPR-uncoupled RyR1 population in WT muscle has a higher propensity to be in the leak conformation. RyR1 leak functions are to keep [Ca2+]rest and the SR Ca2+ content in the physiological range and thus maintain normal intracellular Ca2+ homeostasis.

KW - L-type calcium channel

KW - Resting calcium

UR - http://www.scopus.com/inward/record.url?scp=79955566354&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79955566354&partnerID=8YFLogxK

U2 - 10.1073/pnas.1018380108

DO - 10.1073/pnas.1018380108

M3 - Article

VL - 108

SP - 7046

EP - 7051

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 17

ER -