Tyrosine phosphatase and cytochrome P450 activity are critical in regulating store-operated calcium channels in human fibroblasts.
Diverse signaling pathways have been proposed to regulate store-operated calcium entry (SOCE) in a wide variety of cell types. However, it still needs to be determined if all of these known pathways operate in a single cell type. In this study, we examined involvement of various signaling molecules in SOCE using human fibroblast cells (HSWP). Bradykinin (BK)-stimulated Ca2+ entry, previously shown to be via SOCE, is enhanced by the addition of vanadate, an inhibitor of tyrosine phosphatases. Furthermore, SOCE is regulated by cytochrome P-450, as demonstrated by the fact that the products of cytochrome P-450 activity (14,15 EET) stimulated SOCE while econazole, an inhibitor of cytochrome P450, suppressed BK-stimulated Ca2+ entry. In contrast, Ca2+ entry was unaffected by the guanylate cyclase inhibitor LY83583, or the membrane permeant cyclic GMP analog 8-bromo-cyclic GMP (8-Br-cGMP). Neither nitric oxide donors nor phorbol esters affected BK-stimulated Ca2+ entry. SOCE in HSWP cells is primarily regulated by tyrosine phosphorylation and the cytochrome P-450 pathway, but not by cyclic GMP, nitric oxide, or protein kinase C. Thus, multiple pathways do operate in a single cell type leading to the activation of Ca2+ entry and some of these signaling pathways are more prominently involved in regulating calcium entry in different cell types.
Lee
Kyung-Mi
KM
Department of Biochemistry and Division of Brain Korea 21 Program for Biomedical Science, Korea University College of Medicine, Korea Seoul 136-705, Korea. kyunglee@korea.ac.kr
Son
Sang-Wook
SW
Babnigg
György
G
Villereal
Mitchel L
ML
D001920:Bradykinin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism*; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004464:Econazole / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005347:Fibroblasts; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014638:Vanadates / Q000494:pharmacology
D015220:Calcium Channels; D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D019000:Phosphotyrosine; D009569:Nitric Oxide; D014638:Vanadates; D004815:Epidermal Growth Factor; D004464:Econazole; D003577:Cytochrome P-450 Enzyme System; D017027:Protein Tyrosine Phosphatases; D006152:Cyclic GMP; D013755:Tetradecanoylphorbol Acetate; D001920:Bradykinin; D002118:Calcium