title: cAMP-dependent protein kinase enhances inositol 1,4,5-trisphosphate-induced Ca2+ release in AR4-2J cells.
abstract: In non-excitable cells, the inositol 1,4,5-trisphosphate receptor (IP(3)R), a ligand-gated Ca(2+) channel, plays an important role in the control of intracellular Ca(2+). There are three subtypes of IP(3)R that are differentially distributed among cell types. AR4-2J cells express almost exclusively the IP(3)R-2 subtype. The purpose of this study was to investigate the effect of cAMP-dependent protein kinase (PKA) on the activity of IP(3)R-2 in AR4-2J cells. We showed that immunoprecipitated IP(3)R-2 is a good substrate for PKA. Using a back-phosphorylation approach, we showed that endogenous PKA phosphorylates IP(3)R-2 in intact AR4-2J cells. Pretreatment with PKA enhanced IP(3)-induced Ca(2+) release in permeabilized AR4-2J cells. Pretreatment with the cAMP generating agent's forskolin and vasoactive intestinal peptide (VIP) enhanced carbachol (Cch)-induced and epidermal growth factor (EGF)-induced Ca(2+) responses in intact AR4-2J cells. Our results are consistent with an enhancing effect of PKA on IP(3)R-2 activity. This conclusion supports the emerging concept of crosstalk between Ca(2+) signaling and cAMP pathways and thus provides another way by which Ca(2+) signals are finely encoded within non-excitable cells.
authors.affiliation: Department of Pharmacology, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Quebec J1H5N4, Canada.
authors.forename: Yannik
authors.initials: Y
authors.lastname: Regimbald-Dumas
authors.forename: Guillaume
authors.initials: G
authors.lastname: Arguin
authors.forename: Marc-Olivier
authors.initials: MO
authors.lastname: Fregeau
authors.forename: Gaétan
authors.initials: G
authors.lastname: Guillemette
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D045744:Cell Line, Tumor; D005576:Colforsin / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology*; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010766:Phosphorylation / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D005576:Colforsin; D014660:Vasoactive Intestinal Peptide; D004815:Epidermal Growth Factor; D015544:Inositol 1,4,5-Trisphosphate; D002217:Carbachol; D017868:Cyclic AMP-Dependent Protein Kinases; D002118:Calcium