Intracellular calcium mobilization induces immediate early gene pip92 via Src and mitogen-activated protein kinase in immortalized hippocampal cells.
Regulation of intracellular calcium levels plays a central role in cell survival, proliferation, and differentiation. A cell-permeable, tumor-promoting thapsigargin elevates the intracellular calcium levels by inhibiting endoplasmic reticulum Ca(2+)-ATPase. The Src-tyrosine kinase family is involved in a broad range of cellular responses ranging from cell growth and cytoskeletal rearrangement to differentiation. The immediate early gene pip92 is induced in neuronal cell death as well as cell growth and differentiation. To resolve the molecular mechanism of cell growth by intracellular calcium mobilization, we have examined the effect of thapsigargin and subsequent intracellular calcium influx on pip92 expression in immortalized rat hippocampal H19-7 cells. An increase of intracellular calcium ion levels induced by thapsigargin stimulated the expression of pip92 in H19-7 cells. Transient transfection of the cells with kinase-inactive mitogen-activated protein kinase kinase (MEK) and Src kinase or pretreatment with the chemical MEK inhibitor PD98059 significantly inhibited pip92 expression induced by thapsigargin. When constitutively active v-Src or MEK was overexpressed, the transcriptional activity of the pip92 gene was markedly increased. Dominant inhibitory Raf-1 blocked the transcriptional activity of pip92 induced by thapsigargin. The transcription factor Elk1 is activated during thapsigargin-induced pip92 expression. Taken together, these results suggest that an increase of intracellular calcium ion levels by thapsigargin stimulates the pip92 expression via Raf-MEK-extracellular signal-regulated protein kinase- as well as Src kinase-dependent signaling pathways.
Chung
K C
KC
Department of Pharmacology and Brain Research Institute, Yonsei University College of Medicine, Seoul 120-752, Korea. kchung@yumc.yonsei.ac.kr
Sung
J Y
JY
Ahn
W
W
Rhim
H
H
Oh
T H
TH
Lee
M G
MG
Ahn
Y S
YS
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D004261:DNA Replication / Q000187:drug effects; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics*; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D015221:Potassium Channels / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D051381:Rats; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction; D019284:Thapsigargin / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics*; D050807:ets-Domain Protein Elk-1; D019061:src-Family Kinases / Q000378:metabolism*
D004268:DNA-Binding Proteins; C494114:Elk1 protein, rat; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; C100530:PIP2 protein, S cerevisiae; D015221:Potassium Channels; D011518:Proto-Oncogene Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D019284:Thapsigargin; D019061:src-Family Kinases; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium