16676357

pubmed:Citation

2

The betacellulin precursor (pro-BTC) is a novel substrate for ADAM10-mediated ectodomain shedding. In this report, we investigated the ability of novel physiologically relevant stimuli, including G-protein coupled receptor (GPCR) agonists and reactive oxygen species (ROS), to stimulate pro-BTC shedding. We found that in breast adenocarcinoma MCF7 cells overexpressing pro-BTC, hydrogen peroxide (H2O2) was a powerful stimulator of ectodomain shedding. The stimulation of pro-BTC shedding by H2O2 was blocked by the broad-spectrum metalloprotease inhibitor TAPI-0 but was still functional in ADAM17 (TACE)-deficient stomach epithelial cells indicating the involvement of a distinct metalloprotease. H2O2-induced pro-BTC shedding was blocked by co-culturing cells in the anti-oxidant N-acetyl-L-cysteine but was unaffected by culture in calcium-deficient media. By contrast, calcium ionophore, which is a previously characterized activator of pro-BTC shedding, was sensitive to calcium depletion but was unaffected by co-culture with the anti-oxidant, identifying a clear distinction between these stimuli. We found that in vascular smooth muscle cells overexpressing pro-BTC, the GPCR agonist endothelin-1 (ET-1) was a strong inducer of ectodomain shedding. This was blocked by a metalloprotease inhibitor and by overexpression of catalytically inactive E385A ADAM10. However, overexpression of wild-type ADAM10 or ADAM17 led to an increase in ET-1-induced pro-BTC shedding providing evidence for an involvement of both enzymes in this process. This study identifies ROS and ET-1 as two novel inducers of pro-BTC shedding and lends support to the notion of activated shedding occurring under the control of physiologically relevant stimuli.

eng

IM

MEDLINE

0730-2312

Copyright 2006 Wiley-Liss, Inc.

1

NLM

609-23

pubmed-meshheading:16676357-ADAM Proteins, pubmed-meshheading:16676357-Amyloid Precursor Protein Secretases, pubmed-meshheading:16676357-Animals, pubmed-meshheading:16676357-Breast Neoplasms, pubmed-meshheading:16676357-Calcimycin, pubmed-meshheading:16676357-Cell Line, Tumor, pubmed-meshheading:16676357-Cells, Cultured, pubmed-meshheading:16676357-Dipeptides, pubmed-meshheading:16676357-Endothelin-1, pubmed-meshheading:16676357-Female, pubmed-meshheading:16676357-Humans, pubmed-meshheading:16676357-Hydrogen Peroxide, pubmed-meshheading:16676357-Hydroxamic Acids, pubmed-meshheading:16676357-Intercellular Signaling Peptides and Proteins, pubmed-meshheading:16676357-Intracellular Signaling Peptides and Proteins, pubmed-meshheading:16676357-Membrane Proteins, pubmed-meshheading:16676357-Metalloendopeptidases, pubmed-meshheading:16676357-Mice, pubmed-meshheading:16676357-Muscle, Smooth, Vascular, pubmed-meshheading:16676357-Protein Precursors, pubmed-meshheading:16676357-Protein Structure, Tertiary, pubmed-meshheading:16676357-Rabbits, pubmed-meshheading:16676357-Receptors, G-Protein-Coupled

Hydrogen peroxide and endothelin-1 are novel activators of betacellulin ectodomain shedding.

Journal Article, In Vitro, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural