Abstract
We recently demonstrated that transforming growth factor-β (TGF-β) stimulates phosphorylation of the type I inositol 1,4,5-trisphosphate receptor (Sharma, K., Wang, K., Zhu, Y., Bokkala, S., and Joseph, S. (1997) J. Biol. Chem. 272, 14617-14623), possibly via protein kinase A (PKA) activation in murine mesangial cells. In the present study, we evaluated whether TGF-β stimulates PKA activation. Utilizing a specific PKA kinase assay, we found that TGF-β increases PKA activity by 3-fold within 15 min of TGF-β1 treatment, and the enhanced kinase activity was completely reversed by the inhibitory peptide for PKA (PKI; 1 μM). In mesangial cells transfected with a PKI expression vector, enhanced PKA activity could not be demonstrated with TGF-β1 treatment. TGF-β1 was also found to stimulate translocation of the α-catalytic subunit of PKA to the nucleus by Western analysis of nuclear protein as well as by confocal microscopy. TGF-β1- mediated phosphorylation of cAMP response element-binding protein was completely reversed by H-89 (3 μM), a specific inhibitor of PKA. Stimulation of fibronectin mRNA by TGF-β1 was also attenuated in cells overexpressing PKI. We thus conclude that TGF-β stimulates the PKA signaling pathway in mesangial cells and that PKA activation contributes to TGF-β stimulation of cAMP response element-binding protein phosphorylation and fibronectin expression.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 8522-8527 |
| Number of pages | 6 |
| Journal | Journal of Biological Chemistry |
| Volume | 273 |
| Issue number | 14 |
| DOIs | |
| State | Published - Apr 3 1998 |
| Externally published | Yes |
Fingerprint
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology
Cite this
Transforming growth factor-β1 stimulates protein kinase A in mesangial cells. / Wang, Lewei; Zhu, Yanqing; Sharma, Kumar.
In: Journal of Biological Chemistry, Vol. 273, No. 14, 03.04.1998, p. 8522-8527.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Transforming growth factor-β1 stimulates protein kinase A in mesangial cells
AU - Wang, Lewei
AU - Zhu, Yanqing
AU - Sharma, Kumar
PY - 1998/4/3
Y1 - 1998/4/3
N2 - We recently demonstrated that transforming growth factor-β (TGF-β) stimulates phosphorylation of the type I inositol 1,4,5-trisphosphate receptor (Sharma, K., Wang, K., Zhu, Y., Bokkala, S., and Joseph, S. (1997) J. Biol. Chem. 272, 14617-14623), possibly via protein kinase A (PKA) activation in murine mesangial cells. In the present study, we evaluated whether TGF-β stimulates PKA activation. Utilizing a specific PKA kinase assay, we found that TGF-β increases PKA activity by 3-fold within 15 min of TGF-β1 treatment, and the enhanced kinase activity was completely reversed by the inhibitory peptide for PKA (PKI; 1 μM). In mesangial cells transfected with a PKI expression vector, enhanced PKA activity could not be demonstrated with TGF-β1 treatment. TGF-β1 was also found to stimulate translocation of the α-catalytic subunit of PKA to the nucleus by Western analysis of nuclear protein as well as by confocal microscopy. TGF-β1- mediated phosphorylation of cAMP response element-binding protein was completely reversed by H-89 (3 μM), a specific inhibitor of PKA. Stimulation of fibronectin mRNA by TGF-β1 was also attenuated in cells overexpressing PKI. We thus conclude that TGF-β stimulates the PKA signaling pathway in mesangial cells and that PKA activation contributes to TGF-β stimulation of cAMP response element-binding protein phosphorylation and fibronectin expression.
AB - We recently demonstrated that transforming growth factor-β (TGF-β) stimulates phosphorylation of the type I inositol 1,4,5-trisphosphate receptor (Sharma, K., Wang, K., Zhu, Y., Bokkala, S., and Joseph, S. (1997) J. Biol. Chem. 272, 14617-14623), possibly via protein kinase A (PKA) activation in murine mesangial cells. In the present study, we evaluated whether TGF-β stimulates PKA activation. Utilizing a specific PKA kinase assay, we found that TGF-β increases PKA activity by 3-fold within 15 min of TGF-β1 treatment, and the enhanced kinase activity was completely reversed by the inhibitory peptide for PKA (PKI; 1 μM). In mesangial cells transfected with a PKI expression vector, enhanced PKA activity could not be demonstrated with TGF-β1 treatment. TGF-β1 was also found to stimulate translocation of the α-catalytic subunit of PKA to the nucleus by Western analysis of nuclear protein as well as by confocal microscopy. TGF-β1- mediated phosphorylation of cAMP response element-binding protein was completely reversed by H-89 (3 μM), a specific inhibitor of PKA. Stimulation of fibronectin mRNA by TGF-β1 was also attenuated in cells overexpressing PKI. We thus conclude that TGF-β stimulates the PKA signaling pathway in mesangial cells and that PKA activation contributes to TGF-β stimulation of cAMP response element-binding protein phosphorylation and fibronectin expression.
UR - http://www.scopus.com/inward/record.url?scp=0032478791&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032478791&partnerID=8YFLogxK
U2 - 10.1074/jbc.273.14.8522
DO - 10.1074/jbc.273.14.8522
M3 - Article
C2 - 9525967
AN - SCOPUS:0032478791
VL - 273
SP - 8522
EP - 8527
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 14
ER -