Abstract
A major mechanism for Na+ transport across epithelia occurs through epithelial Na+ channels (ENaC). ENaC is a multimeric channel consisting of three subunits (α, β, and γ). The α-subunit is critical for ENaC function. In specific culture conditions, the rat submandibular gland epithelial cell line (SMG-C6) demonstrates minimal Na + transport properties and exposure to dibutyryl cAMP (DbcAMP) for up to 48 h caused an elevation of α-ENaC mRNA and protein expression and amiloride-sensitive short-circuit current (ISC). Here we examined the early signaling pathways evoked by DbcAMP which contribute to the eventual increase in Na+ transport. Treatment with either of the protein kinase A (PKA) inhibitors KT5720 or H-89 followed by exposure to 1 mM DbcAMP for 24 h markedly attenuated DbcAMP-induced α-ENaC protein formation and ISC. Exposure of SMG-C6 cells to 1 mM DbcAMP induced a rapid, transient phosphorylation of the cAMP response element binding protein (CREB). This response was attenuated in the presence of either KT5720 or H-89. Dominant-negative CREB decreased DbcAMP-induced α-ENaC expression. Suppression of the extracellular signal-regulated protein kinase (ERK 1,2) with PD98059 or the p38 mitogen-activated protein kinase (MAPK) pathway with SB203580 reduced DbcAMP-induced α-ENaC protein levels in SMG-C6 cells. DbcAMP-induced phosphorylation of CREB was markedly attenuated by PD98059 or SB203580. DbcAMP-induced activation of the either the p38 or the ERK 1,2 MAPK pathways was abolished by either of the PKA inhibitors, H-89 or KT5720. Cross talk between these signaling pathways induced by DbcAMP via the activation of CREB appears to contribute to increased levels of α-ENaC observed after 24 h of treatment in SMG-C6 epithelial cells.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 101-110 |
| Number of pages | 10 |
| Journal | Journal of Cellular Physiology |
| Volume | 215 |
| Issue number | 1 |
| DOIs | |
| State | Published - Apr 2008 |
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ASJC Scopus subject areas
- Clinical Biochemistry
- Cell Biology
- Physiology
Cite this
Protein kinase A and mitogen-activated protein kinase pathways mediate cAMP induction of α-epithelial Na+ channels (α-ENaC). / Mustafa, Shamimunisa B; Castro, Robert; Falck, Alison J.; Petershack, Jean O; Henson, Barbara M.; Mendoza, Yvonne M.; Choudary, Ahsan; Seidner, Steven R.
In: Journal of Cellular Physiology, Vol. 215, No. 1, 04.2008, p. 101-110.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Protein kinase A and mitogen-activated protein kinase pathways mediate cAMP induction of α-epithelial Na+ channels (α-ENaC)
AU - Mustafa, Shamimunisa B
AU - Castro, Robert
AU - Falck, Alison J.
AU - Petershack, Jean O
AU - Henson, Barbara M.
AU - Mendoza, Yvonne M.
AU - Choudary, Ahsan
AU - Seidner, Steven R
PY - 2008/4
Y1 - 2008/4
N2 - A major mechanism for Na+ transport across epithelia occurs through epithelial Na+ channels (ENaC). ENaC is a multimeric channel consisting of three subunits (α, β, and γ). The α-subunit is critical for ENaC function. In specific culture conditions, the rat submandibular gland epithelial cell line (SMG-C6) demonstrates minimal Na + transport properties and exposure to dibutyryl cAMP (DbcAMP) for up to 48 h caused an elevation of α-ENaC mRNA and protein expression and amiloride-sensitive short-circuit current (ISC). Here we examined the early signaling pathways evoked by DbcAMP which contribute to the eventual increase in Na+ transport. Treatment with either of the protein kinase A (PKA) inhibitors KT5720 or H-89 followed by exposure to 1 mM DbcAMP for 24 h markedly attenuated DbcAMP-induced α-ENaC protein formation and ISC. Exposure of SMG-C6 cells to 1 mM DbcAMP induced a rapid, transient phosphorylation of the cAMP response element binding protein (CREB). This response was attenuated in the presence of either KT5720 or H-89. Dominant-negative CREB decreased DbcAMP-induced α-ENaC expression. Suppression of the extracellular signal-regulated protein kinase (ERK 1,2) with PD98059 or the p38 mitogen-activated protein kinase (MAPK) pathway with SB203580 reduced DbcAMP-induced α-ENaC protein levels in SMG-C6 cells. DbcAMP-induced phosphorylation of CREB was markedly attenuated by PD98059 or SB203580. DbcAMP-induced activation of the either the p38 or the ERK 1,2 MAPK pathways was abolished by either of the PKA inhibitors, H-89 or KT5720. Cross talk between these signaling pathways induced by DbcAMP via the activation of CREB appears to contribute to increased levels of α-ENaC observed after 24 h of treatment in SMG-C6 epithelial cells.
AB - A major mechanism for Na+ transport across epithelia occurs through epithelial Na+ channels (ENaC). ENaC is a multimeric channel consisting of three subunits (α, β, and γ). The α-subunit is critical for ENaC function. In specific culture conditions, the rat submandibular gland epithelial cell line (SMG-C6) demonstrates minimal Na + transport properties and exposure to dibutyryl cAMP (DbcAMP) for up to 48 h caused an elevation of α-ENaC mRNA and protein expression and amiloride-sensitive short-circuit current (ISC). Here we examined the early signaling pathways evoked by DbcAMP which contribute to the eventual increase in Na+ transport. Treatment with either of the protein kinase A (PKA) inhibitors KT5720 or H-89 followed by exposure to 1 mM DbcAMP for 24 h markedly attenuated DbcAMP-induced α-ENaC protein formation and ISC. Exposure of SMG-C6 cells to 1 mM DbcAMP induced a rapid, transient phosphorylation of the cAMP response element binding protein (CREB). This response was attenuated in the presence of either KT5720 or H-89. Dominant-negative CREB decreased DbcAMP-induced α-ENaC expression. Suppression of the extracellular signal-regulated protein kinase (ERK 1,2) with PD98059 or the p38 mitogen-activated protein kinase (MAPK) pathway with SB203580 reduced DbcAMP-induced α-ENaC protein levels in SMG-C6 cells. DbcAMP-induced phosphorylation of CREB was markedly attenuated by PD98059 or SB203580. DbcAMP-induced activation of the either the p38 or the ERK 1,2 MAPK pathways was abolished by either of the PKA inhibitors, H-89 or KT5720. Cross talk between these signaling pathways induced by DbcAMP via the activation of CREB appears to contribute to increased levels of α-ENaC observed after 24 h of treatment in SMG-C6 epithelial cells.
UR - http://www.scopus.com/inward/record.url?scp=39149104082&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=39149104082&partnerID=8YFLogxK
U2 - 10.1002/jcp.21291
DO - 10.1002/jcp.21291
M3 - Article
C2 - 17960568
AN - SCOPUS:39149104082
VL - 215
SP - 101
EP - 110
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
SN - 0021-9541
IS - 1
ER -