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 -