Tumor necrosis factor-alpha-mediated regulation of the inositol 1,4,5-trisphosphate receptor promoter.
Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, has been implicated as a central mediator in multiple homeostatic and pathologic processes. Signaling cascades downstream of its cellular cognate receptors, as well as the resultant transcriptional responses have received intense interest in regards to how such signals impact cellular physiology. Notably, TNF-alpha was shown to potentiate neuronal Ca(2+) signaling by enhancing type-1 inositol 1,4,5-trisphosphate receptor (IP(3)R) steady-state mRNA levels. In the present study, we sought to determine the promoter region ultimately responsive to TNF-alpha exposure. We report that a sequence encompassing a specificity protein 1 (SP-1) binding site is necessary for TNF-alpha regulation. Electrophoretic mobility shift analysis demonstrated specific binding to this sequence, while site-directed mutagenesis of this site abrogated both JNK-mediated regulation as well as transcription factor binding. Expression of a dominant-negative SP-1 eliminated both the enhanced promoter activity and the elevated IP(3)R-mediated Ca(2+) signals observed with TNF-alpha exposure. Overall, these data delineate a key pathway by which TNF-alpha in a neuronal environment modulates IP(3)R expression and intracellular Ca(2+) homeostasis.
Park
Keigan M
KM
Department of Neurology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York 14642, USA.
Yule
David I
DI
Bowers
William J
WJ
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000235:genetics* / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D019636:Neurodegenerative Diseases / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D016329:Sp1 Transcription Factor / Q000378:metabolism; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D053496:Inositol 1,4,5-Trisphosphate Receptors; D012333:RNA, Messenger; D016329:Sp1 Transcription Factor; D014409:Tumor Necrosis Factor-alpha; D048031:JNK Mitogen-Activated Protein Kinases; D002118:Calcium