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InsP3R-associated cGMP kinase substrate (IRAG) is essential for nitric oxide-induced inhibition of calcium signaling in human colonic smooth muscle.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2004 Mar 26; Vol. 279 (13), pp. 12551-9. Date of Electronic Publication: 2004 Jan 18. - Publication Year :
- 2004
-
Abstract
- Nitric oxide (NO)-mediated relaxation of colonic smooth muscle is crucial for the maintenance of human gut function. The molecular mechanisms of NO-dependent smooth muscle relaxation involve cyclic GMP-mediated inhibition of store-dependent calcium signaling. Recently, IRAG (inositol 1,4,5-trisphophate receptor-associated cGMP kinase substrate) has been characterized as a novel target molecule of cGMP-dependent protein kinase (cGKI) mediating NO-/cGMP-dependent inhibition of inositol 1,4,5-trisphosphate (InsP(3))-dependent calcium release in transfected COS cells. The aim of the present study was to characterize IRAG expression and its functional role in NO-dependent signaling in human colonic smooth muscle. Reverse transcriptase-PCR revealed IRAG mRNA expression in human colon, rectum, and cultured colonic smooth muscle cells. In cultured human colonic smooth muscle cells, bradykinin (BK) elicited InsP(3)-dependent calcium transients that were repeatable and independent of extracellular calcium. The NO donor sodium nitroprusside and the specific cGK activator 8-(4-chlorophenylthio)guanosine-3',5'-cyclic-monophosphate (8-pCPT-cGMP) significantly inhibited BK-induced increase in intracellular calcium. Cells transfected with antisense oligonucleotides raised against IRAG (IRAG-AS) showed strongly decreased IRAG protein expression. In these cells, sodium nitroprusside and 8-pCPT-cGMP both failed to modulate BK-induced calcium transients. Thus, endogenous IRAG appears to be essentially involved in the NO/cGK-dependent inhibition of InsP(3)-dependent Ca(2+)-signaling in colonic smooth muscle.
- Subjects :
- Animals
Blotting, Western
Bradykinin pharmacology
COS Cells
Cells, Cultured
Cyclic GMP pharmacology
Humans
Membrane Proteins
Microscopy, Fluorescence
Myocytes, Smooth Muscle metabolism
Nitric Oxide Donors pharmacology
Nitroprusside pharmacology
Oligonucleotides, Antisense pharmacology
Platelet Aggregation Inhibitors pharmacology
RNA, Messenger metabolism
Rectum metabolism
Reverse Transcriptase Polymerase Chain Reaction
Signal Transduction
Thionucleotides pharmacology
Time Factors
Transfection
Calcium metabolism
Colon metabolism
Cyclic GMP analogs & derivatives
Muscle, Smooth metabolism
Nitric Oxide metabolism
Phosphoproteins chemistry
Phosphoproteins physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 279
- Issue :
- 13
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 14729908
- Full Text :
- https://doi.org/10.1074/jbc.M313365200