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- Title
Chronic regulation of the expression of the gap junction protein connexin 43 in transfected HeLa cells.
- Authors
Salameh, A.; Polontchouk, L.; Dhein, S.; Hagendorff, A.; Pfeiffer, D.
- Abstract
Gap junction channels are essential for intercellular communication. Among the most abundant gap junction channel proteins is connexin 43 (Cx43). The goal of our study was to find out, whether Cx43 content may be regulated via adenylyl cyclase (AC)/cAMP/protein kinase A (PKA), protein kinase C (PKC) pathways or by a tyrosine kinase coupled pathway, i.e. TNFα-receptor dependent pathway. Therefore, we used HeLa cells transfected with Cx43 and exposed these cells for 24 h to either db-cAMP (10-4 M), forskolin (10-5 M), the phorbolester phorbol-12,13-didecanoate PDD (10-7 M) (or its inactive form 4α-PDD), TNFα (10 U/ml) with or without additional treatment with the MAP kinase inhibitors SB203580 (10-5 M, p38 MAP-kinase inhibitor) or the MEK1-inhibitor PD98059 (10-5 M). Cx43 content was analysed using Western blot analysis. All results were confirmed by a second series of identical experiments using Cx43 immunohistochemistry. We found significantly enhanced Cx43 content in cells treated with db-cAMP, forskolin, PDD or TNFα (p<0.05), while 4α-PDD or the solvent DMSO exerted no effect. These increases in Cx43 content could be completely suppressed by SB203580 (p<0.05) but not by PD98059. In absence of a stimulating drug, these inhibitors (SB203580 or PD98059) did not affect Cx43 content. Additional PCR experiments revealed increases in Cx43-mRNA under the influence of db-cAMP, forskolin, PDD or TNFα (p<0.05), which all could be completely suppressed by SB203580. From these results we conclude that1.Cx43 content can be regulated via AC/cAMP/PKA, PKC and TNFα-receptor-dependent pathways2.Activation of p38 MAP kinase is a common pathway for regulation of Cx43 content in HeLa cells
- Subjects
GAP junctions (Cell biology); PROTEIN kinases; CANCER cells; CELL communication; CONNEXINS; FORSKOLIN
- Publication
Naunyn-Schmiedeberg's Archives of Pharmacology, 2003, Vol 368, Issue 1, p33
- ISSN
0028-1298
- Publication type
Article
- DOI
10.1007/s00210-003-0760-1