## Abstract The aseptic loosening of artificial joints with associated periprosthetic bone resorption may be partly due to the suppression of osteoblast function to form new bone by wear debris from the joint. To assess the effect of wear debris on osteoblasts, effects of model wear debris on gap j
Inhibition of connexin43 gap junctional intercellular communication by TPA requires ERK activation
✍ Scribed by Randall J. Ruch; James E. Trosko; Burra V. Madhukar
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 243 KB
- Volume
- 83
- Category
- Article
- ISSN
- 0730-2312
- DOI
- 10.1002/jcb.1227
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
The phorbol ester, 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), is a potent inhibitor of gap junctional intercellular communication (GJIC). This inhibition requires activation of protein kinase C (PKC), but the events downstream of this kinase are not known. Since PKC can activate extracellular signal regulated kinases (ERKs) and these also downregulate GJIC, we hypothesized that the inhibition of GJIC by TPA involved ERKs. TPA treatment (10 ng/ml for 30 min) of WB‐F344 rat liver epithelial cells strongly activated p42 and p44 ERK‐1 and ‐2, blocked gap junction‐mediated fluorescent dye‐coupling, and induced connexin43 hyperphosphorylation and gap junction internalization. These effects were completely prevented by inhibitors of PKC (bis‐indolylmaleimide I; 2 μM) and ERK activation (U‐0126; 10 μM). These data suggest that ERKs are activated by PKC in response to TPA treatment and are downstream mediators of the gap junction effects of the phorbol ester. J. Cell. Biochem. 83: 163–169, 2001. © 2001 Wiley‐Liss, Inc.
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