Abstract
The calcium-sensing receptor (CaR) is an allosteric protein that responds to extracellular Ca2+ ([Ca2+]o) and aromatic amino acids with the production of different patterns of oscillations in intracellular Ca2+ concentration ([Ca2+]i). An increase in [Ca2+]o stimulates phospholipase C-mediated production of inositol 1,4,5-trisphosphate and causes sinusoidal oscillations in [Ca2+]i. Conversely, aromatic amino acid-induced CaR activation does not stimulate phospholipase C but engages an unidentified signaling mechanism that promotes transient oscillations in [Ca 2+]i. We show here that the [Ca2+]i oscillations stimulated by aromatic amino acids were selectively abolished by TRPC1 down-regulation using either a pool of small inhibitory RNAs (siRNAs) or two different individual siRNAs that targeted different coding regions of TRPC1. Furthermore, [Ca2+]i oscillations stimulated by aromatic amino acids were also abolished by inhibition of TRPC1 function with an antibody that binds the pore region of the channel. We also show that aromatic amino acid-stimulated [Ca2+]i oscillations can be prevented by protein kinase C (PKC) inhibitors or siRNA-mediated PKCα down-regulation and impaired by either calmodulin antagonists or by the expression of a dominant-negative calmodulin mutant. We propose a model for the generation of CaR-mediated transient [Ca2+]i oscillations that integrates its stimulation by aromatic amino acids with TRPC1 regulation by PKC and calmodulin.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 38730-38737 |
| Number of pages | 8 |
| Journal | Journal of Biological Chemistry |
| Volume | 281 |
| Issue number | 50 |
| DOIs | |
| State | Published - Dec 15 2006 |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Requirement of the TRPC1 cation channel in the generation of transient Ca2+ oscillations by the calcium-sensing receptor. / Rey, Osvaldo; Young, Steven H.; Papazyan, Romeo; Shapiro, Mark S; Rozengurt, Enrique.
In: Journal of Biological Chemistry, Vol. 281, No. 50, 15.12.2006, p. 38730-38737.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Requirement of the TRPC1 cation channel in the generation of transient Ca2+ oscillations by the calcium-sensing receptor
AU - Rey, Osvaldo
AU - Young, Steven H.
AU - Papazyan, Romeo
AU - Shapiro, Mark S
AU - Rozengurt, Enrique
PY - 2006/12/15
Y1 - 2006/12/15
N2 - The calcium-sensing receptor (CaR) is an allosteric protein that responds to extracellular Ca2+ ([Ca2+]o) and aromatic amino acids with the production of different patterns of oscillations in intracellular Ca2+ concentration ([Ca2+]i). An increase in [Ca2+]o stimulates phospholipase C-mediated production of inositol 1,4,5-trisphosphate and causes sinusoidal oscillations in [Ca2+]i. Conversely, aromatic amino acid-induced CaR activation does not stimulate phospholipase C but engages an unidentified signaling mechanism that promotes transient oscillations in [Ca 2+]i. We show here that the [Ca2+]i oscillations stimulated by aromatic amino acids were selectively abolished by TRPC1 down-regulation using either a pool of small inhibitory RNAs (siRNAs) or two different individual siRNAs that targeted different coding regions of TRPC1. Furthermore, [Ca2+]i oscillations stimulated by aromatic amino acids were also abolished by inhibition of TRPC1 function with an antibody that binds the pore region of the channel. We also show that aromatic amino acid-stimulated [Ca2+]i oscillations can be prevented by protein kinase C (PKC) inhibitors or siRNA-mediated PKCα down-regulation and impaired by either calmodulin antagonists or by the expression of a dominant-negative calmodulin mutant. We propose a model for the generation of CaR-mediated transient [Ca2+]i oscillations that integrates its stimulation by aromatic amino acids with TRPC1 regulation by PKC and calmodulin.
AB - The calcium-sensing receptor (CaR) is an allosteric protein that responds to extracellular Ca2+ ([Ca2+]o) and aromatic amino acids with the production of different patterns of oscillations in intracellular Ca2+ concentration ([Ca2+]i). An increase in [Ca2+]o stimulates phospholipase C-mediated production of inositol 1,4,5-trisphosphate and causes sinusoidal oscillations in [Ca2+]i. Conversely, aromatic amino acid-induced CaR activation does not stimulate phospholipase C but engages an unidentified signaling mechanism that promotes transient oscillations in [Ca 2+]i. We show here that the [Ca2+]i oscillations stimulated by aromatic amino acids were selectively abolished by TRPC1 down-regulation using either a pool of small inhibitory RNAs (siRNAs) or two different individual siRNAs that targeted different coding regions of TRPC1. Furthermore, [Ca2+]i oscillations stimulated by aromatic amino acids were also abolished by inhibition of TRPC1 function with an antibody that binds the pore region of the channel. We also show that aromatic amino acid-stimulated [Ca2+]i oscillations can be prevented by protein kinase C (PKC) inhibitors or siRNA-mediated PKCα down-regulation and impaired by either calmodulin antagonists or by the expression of a dominant-negative calmodulin mutant. We propose a model for the generation of CaR-mediated transient [Ca2+]i oscillations that integrates its stimulation by aromatic amino acids with TRPC1 regulation by PKC and calmodulin.
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U2 - 10.1074/jbc.M605956200
DO - 10.1074/jbc.M605956200
M3 - Article
VL - 281
SP - 38730
EP - 38737
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 50
ER -