RyR1-specific requirement for depolarization-induced Ca2+ sparks in urinary bladder smooth muscle

Nicolas Fritz, Jean Luc Morel, Loice H. Jeyakumar, Sidney Fleischer, Paul D. Allen, Jean Mironneau, Nathalie Macrez

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Ryanodine receptor subtype 1 (RyR1) has been primarily characterized in skeletal muscle but several studies have revealed its expression in smooth muscle. Here, we used Ryr1-null mice to investigate the role of this isoform in Ca2+ signaling in urinary bladder smooth muscle. We show that RyR1 is required for depolarization-induced Ca2+ sparks, whereas RyR2 and RyR3 are sufficient for spontaneous or caffeine-induced Ca2+ sparks. Immunostaining revealed specific subcellular localization of RyR1 in the superficial sarcoplasmic reticulum; by contrast, RyR2 and RyR3 are mainly expressed in the deep sarcoplasmic reticulum. Paradoxically, lack of depolarization-induced Ca2+ sparks in Ryr1-/ - myocytes was accompanied by an increased number of cells displaying spontaneous or depolarization-induced Ca2+ waves. Investigation of protein expression showed that FK506-binding protein (FKBP) 12 and FKBP12.6 (both of which are RyR-associated proteins) are downregulated in Ryr1-/- myocytes, whereas expression of RyR2 and RyR3 are unchanged. Moreover, treatment with rapamycin, which uncouples FKBPs from RyR, led to an increase of RyR-dependent Ca2+ signaling in wild-type urinary bladder myocytes but not in Ryr1-/- myocytes. In conclusion, although decreased amounts of FKBP increase Ca2+ signals in Ryr1-/- urinary bladder myocytes the depolarization-induced Ca2+ sparks are specifically lost, demonstrating that RyR1 is required for depolarization-induced Ca2+ sparks and suggesting that the intracellular localization of RyR1 fine-tunes Ca2+ signals in smooth muscle.

Original languageEnglish (US)
Pages (from-to)3784-3791
Number of pages8
JournalJournal of Cell Science
Volume120
Issue number21
DOIs
StatePublished - Nov 1 2007
Externally publishedYes

Fingerprint

Ryanodine Receptor Calcium Release Channel
Smooth Muscle
Urinary Bladder
Muscle Cells
Tacrolimus Binding Proteins
Sarcoplasmic Reticulum
Sirolimus
Caffeine

Keywords

  • Ca sparks
  • FK506-binding protein
  • Ryanodine receptors
  • Ryr1 mice
  • Smooth muscle

ASJC Scopus subject areas

  • Cell Biology

Cite this

Fritz, N., Morel, J. L., Jeyakumar, L. H., Fleischer, S., Allen, P. D., Mironneau, J., & Macrez, N. (2007). RyR1-specific requirement for depolarization-induced Ca2+ sparks in urinary bladder smooth muscle. Journal of Cell Science, 120(21), 3784-3791. https://doi.org/10.1242/jcs.009415

RyR1-specific requirement for depolarization-induced Ca2+ sparks in urinary bladder smooth muscle. / Fritz, Nicolas; Morel, Jean Luc; Jeyakumar, Loice H.; Fleischer, Sidney; Allen, Paul D.; Mironneau, Jean; Macrez, Nathalie.

In: Journal of Cell Science, Vol. 120, No. 21, 01.11.2007, p. 3784-3791.

Research output: Contribution to journalArticle

Fritz, N, Morel, JL, Jeyakumar, LH, Fleischer, S, Allen, PD, Mironneau, J & Macrez, N 2007, 'RyR1-specific requirement for depolarization-induced Ca2+ sparks in urinary bladder smooth muscle', Journal of Cell Science, vol. 120, no. 21, pp. 3784-3791. https://doi.org/10.1242/jcs.009415
Fritz N, Morel JL, Jeyakumar LH, Fleischer S, Allen PD, Mironneau J et al. RyR1-specific requirement for depolarization-induced Ca2+ sparks in urinary bladder smooth muscle. Journal of Cell Science. 2007 Nov 1;120(21):3784-3791. https://doi.org/10.1242/jcs.009415
Fritz, Nicolas ; Morel, Jean Luc ; Jeyakumar, Loice H. ; Fleischer, Sidney ; Allen, Paul D. ; Mironneau, Jean ; Macrez, Nathalie. / RyR1-specific requirement for depolarization-induced Ca2+ sparks in urinary bladder smooth muscle. In: Journal of Cell Science. 2007 ; Vol. 120, No. 21. pp. 3784-3791.
@article{236c094ae6d64be983183689065f5aab,
title = "RyR1-specific requirement for depolarization-induced Ca2+ sparks in urinary bladder smooth muscle",
abstract = "Ryanodine receptor subtype 1 (RyR1) has been primarily characterized in skeletal muscle but several studies have revealed its expression in smooth muscle. Here, we used Ryr1-null mice to investigate the role of this isoform in Ca2+ signaling in urinary bladder smooth muscle. We show that RyR1 is required for depolarization-induced Ca2+ sparks, whereas RyR2 and RyR3 are sufficient for spontaneous or caffeine-induced Ca2+ sparks. Immunostaining revealed specific subcellular localization of RyR1 in the superficial sarcoplasmic reticulum; by contrast, RyR2 and RyR3 are mainly expressed in the deep sarcoplasmic reticulum. Paradoxically, lack of depolarization-induced Ca2+ sparks in Ryr1-/ - myocytes was accompanied by an increased number of cells displaying spontaneous or depolarization-induced Ca2+ waves. Investigation of protein expression showed that FK506-binding protein (FKBP) 12 and FKBP12.6 (both of which are RyR-associated proteins) are downregulated in Ryr1-/- myocytes, whereas expression of RyR2 and RyR3 are unchanged. Moreover, treatment with rapamycin, which uncouples FKBPs from RyR, led to an increase of RyR-dependent Ca2+ signaling in wild-type urinary bladder myocytes but not in Ryr1-/- myocytes. In conclusion, although decreased amounts of FKBP increase Ca2+ signals in Ryr1-/- urinary bladder myocytes the depolarization-induced Ca2+ sparks are specifically lost, demonstrating that RyR1 is required for depolarization-induced Ca2+ sparks and suggesting that the intracellular localization of RyR1 fine-tunes Ca2+ signals in smooth muscle.",
keywords = "Ca sparks, FK506-binding protein, Ryanodine receptors, Ryr1 mice, Smooth muscle",
author = "Nicolas Fritz and Morel, {Jean Luc} and Jeyakumar, {Loice H.} and Sidney Fleischer and Allen, {Paul D.} and Jean Mironneau and Nathalie Macrez",
year = "2007",
month = "11",
day = "1",
doi = "10.1242/jcs.009415",
language = "English (US)",
volume = "120",
pages = "3784--3791",
journal = "Journal of Cell Science",
issn = "0021-9533",
publisher = "Company of Biologists Ltd",
number = "21",

}

TY - JOUR

T1 - RyR1-specific requirement for depolarization-induced Ca2+ sparks in urinary bladder smooth muscle

AU - Fritz, Nicolas

AU - Morel, Jean Luc

AU - Jeyakumar, Loice H.

AU - Fleischer, Sidney

AU - Allen, Paul D.

AU - Mironneau, Jean

AU - Macrez, Nathalie

PY - 2007/11/1

Y1 - 2007/11/1

N2 - Ryanodine receptor subtype 1 (RyR1) has been primarily characterized in skeletal muscle but several studies have revealed its expression in smooth muscle. Here, we used Ryr1-null mice to investigate the role of this isoform in Ca2+ signaling in urinary bladder smooth muscle. We show that RyR1 is required for depolarization-induced Ca2+ sparks, whereas RyR2 and RyR3 are sufficient for spontaneous or caffeine-induced Ca2+ sparks. Immunostaining revealed specific subcellular localization of RyR1 in the superficial sarcoplasmic reticulum; by contrast, RyR2 and RyR3 are mainly expressed in the deep sarcoplasmic reticulum. Paradoxically, lack of depolarization-induced Ca2+ sparks in Ryr1-/ - myocytes was accompanied by an increased number of cells displaying spontaneous or depolarization-induced Ca2+ waves. Investigation of protein expression showed that FK506-binding protein (FKBP) 12 and FKBP12.6 (both of which are RyR-associated proteins) are downregulated in Ryr1-/- myocytes, whereas expression of RyR2 and RyR3 are unchanged. Moreover, treatment with rapamycin, which uncouples FKBPs from RyR, led to an increase of RyR-dependent Ca2+ signaling in wild-type urinary bladder myocytes but not in Ryr1-/- myocytes. In conclusion, although decreased amounts of FKBP increase Ca2+ signals in Ryr1-/- urinary bladder myocytes the depolarization-induced Ca2+ sparks are specifically lost, demonstrating that RyR1 is required for depolarization-induced Ca2+ sparks and suggesting that the intracellular localization of RyR1 fine-tunes Ca2+ signals in smooth muscle.

AB - Ryanodine receptor subtype 1 (RyR1) has been primarily characterized in skeletal muscle but several studies have revealed its expression in smooth muscle. Here, we used Ryr1-null mice to investigate the role of this isoform in Ca2+ signaling in urinary bladder smooth muscle. We show that RyR1 is required for depolarization-induced Ca2+ sparks, whereas RyR2 and RyR3 are sufficient for spontaneous or caffeine-induced Ca2+ sparks. Immunostaining revealed specific subcellular localization of RyR1 in the superficial sarcoplasmic reticulum; by contrast, RyR2 and RyR3 are mainly expressed in the deep sarcoplasmic reticulum. Paradoxically, lack of depolarization-induced Ca2+ sparks in Ryr1-/ - myocytes was accompanied by an increased number of cells displaying spontaneous or depolarization-induced Ca2+ waves. Investigation of protein expression showed that FK506-binding protein (FKBP) 12 and FKBP12.6 (both of which are RyR-associated proteins) are downregulated in Ryr1-/- myocytes, whereas expression of RyR2 and RyR3 are unchanged. Moreover, treatment with rapamycin, which uncouples FKBPs from RyR, led to an increase of RyR-dependent Ca2+ signaling in wild-type urinary bladder myocytes but not in Ryr1-/- myocytes. In conclusion, although decreased amounts of FKBP increase Ca2+ signals in Ryr1-/- urinary bladder myocytes the depolarization-induced Ca2+ sparks are specifically lost, demonstrating that RyR1 is required for depolarization-induced Ca2+ sparks and suggesting that the intracellular localization of RyR1 fine-tunes Ca2+ signals in smooth muscle.

KW - Ca sparks

KW - FK506-binding protein

KW - Ryanodine receptors

KW - Ryr1 mice

KW - Smooth muscle

UR - http://www.scopus.com/inward/record.url?scp=36549006968&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=36549006968&partnerID=8YFLogxK

U2 - 10.1242/jcs.009415

DO - 10.1242/jcs.009415

M3 - Article

C2 - 17925380

AN - SCOPUS:36549006968

VL - 120

SP - 3784

EP - 3791

JO - Journal of Cell Science

JF - Journal of Cell Science

SN - 0021-9533

IS - 21

ER -