Abstract
The transcriptional induction of SPRR1B by phorbol 12-myristate 13-acetate (PMA) is mainly mediated by the first -152-base pair 5'-flanking region containing two functional AP-1 sites. In this study, we have analyzed the signaling pathways that mediate the induction in tracheobronchial epithelial cells. PKC inhibitor ablated PMA-stimulated expression of endogenous SPRR1B and reporter gene expression driven by SPRR1B promoter. PKC activator promoted the transcription. The dominant negative protein kinase Cdelta (dn-PKCdelta) and rottlerin (PKCdelta inhibitor) completely suppressed PMA-stimulated promoter activity. dn-Ras or dn-MEKK1 inhibited PMA-stimulated promoter activity, while their corresponding constitutively active mutants augmented it. dn-c-Raf-1 did not have any effect on reporter gene expression. Since MEKK1 activates multiple parallel pathways, we examined involvement of JNK/SAPK, p38, and MKK1 in promoter regulation. Co-expression of the dominant negative forms of MKK4, MKK7, JNK/SAPK, MKK3, MKK6, or p38alpha did not suppress PMA-stimulated reporter gene expression. However, MKK1 inhibitors UO126 and PD98095 suppressed gene expression. Consistent with this, expression of dn-MKK1 strongly suppressed PMA-stimulated promoter activity, while the constitutively active MKK1 augmented it. However, MKK1-mediated induction of SPRR1B probably does not depend on extracellular signal-regulated kinases 1 and 2, suggesting the requirement of another kinase(s). dn-c-Jun mutants abolished PMA-stimulated expression supporting an important role for AP-1 proteins in SPRR1B expression. Together, these results suggest that a PKCdelta/Ras/MEKK1/MKK1-dependent/AP-1 pathway regulates the PMA-inducible expression of the SPRR1B in tracheobronchial epithelial cells.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Cell Differentiation
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Cell Line
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Cornified Envelope Proline-Rich Proteins
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Epithelial Cells / cytology
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Epithelial Cells / drug effects
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Epithelial Cells / enzymology
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Epithelial Cells / metabolism
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Gene Expression Regulation / drug effects*
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Genes, Reporter
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Genes, jun / genetics
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Humans
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Isoenzymes / antagonists & inhibitors
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Isoenzymes / metabolism*
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MAP Kinase Kinase 1
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MAP Kinase Kinase Kinase 1*
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MAP Kinase Signaling System / drug effects*
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Membrane Proteins
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Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors
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Mitogen-Activated Protein Kinase Kinases / genetics
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Mitogen-Activated Protein Kinase Kinases / metabolism
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Mitogen-Activated Protein Kinases / antagonists & inhibitors
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Mitogen-Activated Protein Kinases / genetics
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Mitogen-Activated Protein Kinases / metabolism
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Models, Biological
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Mutation / genetics
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Promoter Regions, Genetic / genetics
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Protein Kinase C / antagonists & inhibitors
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Protein Kinase C / metabolism*
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Protein Kinase C-delta
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Protein Serine-Threonine Kinases / antagonists & inhibitors
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism
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Proteins / genetics*
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Proteins / metabolism
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Respiratory System / cytology
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Respiratory System / drug effects
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Respiratory System / enzymology
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Respiratory System / metabolism
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Tetradecanoylphorbol Acetate / pharmacology*
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Transcription Factor AP-1 / metabolism*
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ras Proteins / metabolism*
Substances
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Cornified Envelope Proline-Rich Proteins
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Isoenzymes
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Membrane Proteins
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Proteins
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RNA, Messenger
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Transcription Factor AP-1
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SPRR1B protein, human
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Protein Serine-Threonine Kinases
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PRKCD protein, human
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Protein Kinase C
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Protein Kinase C-delta
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Mitogen-Activated Protein Kinases
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MAP Kinase Kinase Kinase 1
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MAP3K1 protein, human
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MAP Kinase Kinase 1
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MAP2K1 protein, human
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Mitogen-Activated Protein Kinase Kinases
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ras Proteins
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Tetradecanoylphorbol Acetate