| RRC ID |
3378
|
| 著者 |
Espelt MV, Estevez AY, Yin X, Strange K.
|
| タイトル |
Oscillatory Ca2+ signaling in the isolated Caenorhabditis elegans intestine: role of the inositol-1,4,5-trisphosphate receptor and phospholipases C beta and gamma.
|
| ジャーナル |
J Gen Physiol
|
| 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.
|
| 巻・号 |
126(4)
|
| ページ |
379-92
|
| 公開日 |
2005-10-1
|
| DOI |
10.1085/jgp.200509355
|
| PII |
jgp.200509355
|
| PMID |
16186564
|
| PMC |
PMC2266627
|
| MeSH |
Animals
Caenorhabditis elegans
Calcium / metabolism*
Calcium Channels / genetics
Calcium Channels / metabolism*
Calcium Signaling / physiology*
Epithelial Cells / metabolism
In Vitro Techniques
Inositol 1,4,5-Trisphosphate / metabolism
Inositol 1,4,5-Trisphosphate Receptors
Intestinal Mucosa / metabolism*
Intracellular Fluid / metabolism
Isoenzymes / genetics
Isoenzymes / metabolism*
Muscle Contraction / physiology
Mutation
Myocytes, Smooth Muscle / metabolism
Phospholipase C beta
Phospholipase C gamma / genetics
Phospholipase C gamma / metabolism*
RNA Interference
Receptors, Cytoplasmic and Nuclear / genetics
Receptors, Cytoplasmic and Nuclear / metabolism*
Time Factors
Type C Phospholipases / genetics
Type C Phospholipases / metabolism*
|
| IF |
3.628
|
| 引用数 |
106
|
|
WOS 分野
|
PHYSIOLOGY
|
| リソース情報 |
| 線虫 |
tm1340 |
