Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10801972 | Biochimica et Biophysica Acta (BBA) - Molecular Cell Research | 2015 | 10 Pages |
Abstract
Amino acid (AA) deprivation in mammalian cells activates a collection of signaling cascades known as the AA response (AAR), which is characterized by transcriptional induction of stress-related genes, including FBJ murine osteosarcoma viral oncogene homolog (cFOS). The present study established that the signaling mechanism underlying the AA-dependent transcriptional regulation of the cFOS gene in HepG2 human hepatocellular carcinoma cells is independent of the classic GCN2-eIF2-ATF4 pathway. Instead, a RAS-RAF-MEK-ERK cascade mediates AAR signaling to the cFOS gene. Increased cFOS transcription is observed from 4-24Â h after AAR-activation, exhibiting little or no overlap with the rapid and transient increase triggered by the well-known serum response. Furthermore, serum is not required for the AA-responsiveness of the cFOS gene and no phosphorylation of promoter-bound serum response factor (SRF) is observed. The ERK-phosphorylated transcription factor E-twenty six-like (p-ELK1) is increased in its association with the cFOS promoter after activation of the AAR. This research identified cFOS as a target of the AAR and further highlights the importance of AA-responsive MAPK signaling in HepG2 cells.
Keywords
AsnSFBJ murine osteosarcoma viral oncogene homologcFoseIF2TETAARERKActDGAPDHMEFJun N-terminal kinaseATF4qPCRDOXJnkGCN2MAPKMAPK/ERK kinaseasparagine synthetaseamino acidactinomycin DTetracyclinedoxycyclinequantitative real time PCRextracellular-signal regulated kinaseeukaryotic initiation factor 2activating transcription factor 4MEKNutrient deprivationmouse embryonic fibroblastsmitogen-activated protein kinaseHepatocellular carcinomageneral control non-derepressible 2glyceraldehyde 3-phosphate dehydrogenase
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Authors
Jixiu Shan, William Donelan, Jaclyn N. Hayner, Fan Zhang, Elizabeth E. Dudenhausen, Michael S. Kilberg,