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Oscillatory Ca2+ signaling in the isolated Caenorhabditis elegans intestine: role of the inositol-1,4,5-trisphosphate receptor and phospholipases C beta and gamma.
J Gen Physiol. 2005 Oct; 126(4):379-92.JG

Abstract

Defecation in the nematode Caenorhabditis elegans is a readily observable ultradian behavioral rhythm that occurs once every 45-50 s and is mediated in part by posterior body wall muscle contraction (pBoc). pBoc is not regulated by neural input but instead is likely controlled by rhythmic Ca(2+) oscillations in the intestinal epithelium. We developed an isolated nematode intestine preparation that allows combined physiological, genetic, and molecular characterization of oscillatory Ca(2+) signaling. Isolated intestines loaded with fluo-4 AM exhibit spontaneous rhythmic Ca(2+) oscillations with a period of approximately 50 s. Oscillations were only detected in the apical cell pole of the intestinal epithelium and occur as a posterior-to-anterior moving intercellular Ca(2+) wave. Loss-of-function mutations in the inositol-1,4,5-trisphosphate (IP(3)) receptor ITR-1 reduce pBoc and Ca(2+) oscillation frequency and intercellular Ca(2+) wave velocity. In contrast, gain-of-function mutations in the IP(3) binding and regulatory domains of ITR-1 have no effect on pBoc or Ca(2+) oscillation frequency but dramatically increase the speed of the intercellular Ca(2+) wave. Systemic RNA interference (RNAi) screening of the six C. elegans phospholipase C (PLC)-encoding genes demonstrated that pBoc and Ca(2+) oscillations require the combined function of PLC-gamma and PLC-beta homologues. Disruption of PLC-gamma and PLC-beta activity by mutation or RNAi induced arrhythmia in pBoc and intestinal Ca(2+) oscillations. The function of the two enzymes is additive. Epistasis analysis suggests that PLC-gamma functions primarily to generate IP(3) that controls ITR-1 activity. In contrast, IP(3) generated by PLC-beta appears to play little or no direct role in ITR-1 regulation. PLC-beta may function instead to control PIP(2) levels and/or G protein signaling events. Our findings provide new insights into intestinal cell Ca(2+) signaling mechanisms and establish C. elegans as a powerful model system for defining the gene networks and molecular mechanisms that underlie the generation and regulation of Ca(2+) oscillations and intercellular Ca(2+) waves in nonexcitable cells.

Authors+Show Affiliations

Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

16186564

Citation

Espelt, Maria V., et al. "Oscillatory Ca2+ Signaling in the Isolated Caenorhabditis Elegans Intestine: Role of the Inositol-1,4,5-trisphosphate Receptor and Phospholipases C Beta and Gamma." The Journal of General Physiology, vol. 126, no. 4, 2005, pp. 379-92.
Espelt MV, Estevez AY, Yin X, et al. Oscillatory Ca2+ signaling in the isolated Caenorhabditis elegans intestine: role of the inositol-1,4,5-trisphosphate receptor and phospholipases C beta and gamma. J Gen Physiol. 2005;126(4):379-92.
Espelt, M. V., Estevez, A. Y., Yin, X., & Strange, K. (2005). Oscillatory Ca2+ signaling in the isolated Caenorhabditis elegans intestine: role of the inositol-1,4,5-trisphosphate receptor and phospholipases C beta and gamma. The Journal of General Physiology, 126(4), 379-92.
Espelt MV, et al. Oscillatory Ca2+ Signaling in the Isolated Caenorhabditis Elegans Intestine: Role of the Inositol-1,4,5-trisphosphate Receptor and Phospholipases C Beta and Gamma. J Gen Physiol. 2005;126(4):379-92. PubMed PMID: 16186564.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Oscillatory Ca2+ signaling in the isolated Caenorhabditis elegans intestine: role of the inositol-1,4,5-trisphosphate receptor and phospholipases C beta and gamma. AU - Espelt,Maria V, AU - Estevez,Ana Y, AU - Yin,Xiaoyan, AU - Strange,Kevin, PY - 2005/9/28/pubmed PY - 2005/12/13/medline PY - 2005/9/28/entrez SP - 379 EP - 92 JF - The Journal of general physiology JO - J Gen Physiol VL - 126 IS - 4 N2 - Defecation in the nematode Caenorhabditis elegans is a readily observable ultradian behavioral rhythm that occurs once every 45-50 s and is mediated in part by posterior body wall muscle contraction (pBoc). pBoc is not regulated by neural input but instead is likely controlled by rhythmic Ca(2+) oscillations in the intestinal epithelium. We developed an isolated nematode intestine preparation that allows combined physiological, genetic, and molecular characterization of oscillatory Ca(2+) signaling. Isolated intestines loaded with fluo-4 AM exhibit spontaneous rhythmic Ca(2+) oscillations with a period of approximately 50 s. Oscillations were only detected in the apical cell pole of the intestinal epithelium and occur as a posterior-to-anterior moving intercellular Ca(2+) wave. Loss-of-function mutations in the inositol-1,4,5-trisphosphate (IP(3)) receptor ITR-1 reduce pBoc and Ca(2+) oscillation frequency and intercellular Ca(2+) wave velocity. In contrast, gain-of-function mutations in the IP(3) binding and regulatory domains of ITR-1 have no effect on pBoc or Ca(2+) oscillation frequency but dramatically increase the speed of the intercellular Ca(2+) wave. Systemic RNA interference (RNAi) screening of the six C. elegans phospholipase C (PLC)-encoding genes demonstrated that pBoc and Ca(2+) oscillations require the combined function of PLC-gamma and PLC-beta homologues. Disruption of PLC-gamma and PLC-beta activity by mutation or RNAi induced arrhythmia in pBoc and intestinal Ca(2+) oscillations. The function of the two enzymes is additive. Epistasis analysis suggests that PLC-gamma functions primarily to generate IP(3) that controls ITR-1 activity. In contrast, IP(3) generated by PLC-beta appears to play little or no direct role in ITR-1 regulation. PLC-beta may function instead to control PIP(2) levels and/or G protein signaling events. Our findings provide new insights into intestinal cell Ca(2+) signaling mechanisms and establish C. elegans as a powerful model system for defining the gene networks and molecular mechanisms that underlie the generation and regulation of Ca(2+) oscillations and intercellular Ca(2+) waves in nonexcitable cells. SN - 0022-1295 UR - https://www.unboundmedicine.com/medline/citation/16186564/Oscillatory_Ca2+_signaling_in_the_isolated_Caenorhabditis_elegans_intestine:_role_of_the_inositol_145_trisphosphate_receptor_and_phospholipases_C_beta_and_gamma_ L2 - https://rupress.org/jgp/article-lookup/doi/10.1085/jgp.200509355 DB - PRIME DP - Unbound Medicine ER -