Increase in IP3 and intracellular Ca2+ induced by phosphate depletion in LLC-PK 1 cells.
The mechanisms by which Pi depletion rapidly regulates gene expression and cellular function have not been clarified. Here, we found a rapid increase in intracellular ionized calcium [Ca(2+)](i) by phosphate depletion in LLC-PK(1) cells using confocal microscopy with the green-fluorescence protein based calcium indicator "yellow cameleon 2.1." The increase of [Ca(2+)](i) was observed in the presence or absence of extracellular Ca(2+). At the same time, an approximately twofold increase in intracellular inositol 1,4,5-triphosphate (IP(3)) occurred in response to the acute Pi depletion in the medium. Furthermore, 2-aminoethoxydiphenyl borate completely blocked the [Ca(2+)](i) increase induced by Pi depletion. These results suggest that Pi depletion causes IP(3)-mediated release of Ca(2+) from intracellular Ca(2+) pools and rapidly increases [Ca(2+)](i) in LLC-PK(1) cells.
Taketani
Yutaka
Y
Department of Clinical Nutrition, School of Medicine, University of Tokushima, 770-8503, Tokushima, Japan. taketani@nutr.med.tokushima-u.ac.jp
Nomoto
Mayumi
M
Yamamoto
Hironori
H
Isshiki
Masashi
M
Morita
Kyoko
K
Arai
Hidekazu
H
Miyamoto
Ken-ichi
K
Kato
Shigeaki
S
Takeda
Eiji
E
D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D018613:Microscopy, Confocal; D010710:Phosphates / Q000502:physiology*; D051381:Rats
D001896:Boron Compounds; D010710:Phosphates; D015544:Inositol 1,4,5-Trisphosphate; C109986:2-aminoethoxydiphenyl borate; D002118:Calcium