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TACE/ADAM-17 enzymatic activity is increased in response to cellular stimulation
John R Doedens1, Rajeev M Mahimkar, Roy A Black
1Department of Cell Biology, Amgen Inc., 51 University St., Seattle, WA 98101, USA. doedensj@amgen.com
Biochemical and Biophysical Research Communications
|August 7, 2003
Summary
Tumor necrosis factor-alpha converting enzyme (TACE/ADAM-17) activity increases upon cell stimulation, enhancing protein shedding. This induced TACE activity is independent of its cytoplasmic domain and cell surface levels.
Area of Science:
- Biochemistry
- Cell Biology
- Enzymology
Background:
- Tumor necrosis factor-alpha converting enzyme (TACE/ADAM-17) is a metalloprotease responsible for shedding membrane proteins.
- TACE-mediated shedding occurs at basal rates, but can be enhanced by cellular stimuli.
Purpose of the Study:
- To investigate the mechanism behind induced TACE-mediated shedding.
- To quantify cellular TACE activity using a novel peptide-cleavage assay.
Main Methods:
- Development of a peptide-cleavage assay to measure cellular TACE activity.
- Stimulation of cells with phorbol-12-myristate-13-acetate (PMA).
- Analysis of TACE levels on the cell surface and the role of its cytoplasmic domain.
Main Results:
- In unstimulated cells, TACE was not the primary enzyme for peptide cleavage.
- PMA stimulation significantly increased TACE-dependent peptide cleavage.
- PMA treatment did not alter cell surface TACE levels or require its cytoplasmic domain for induced activity.
Conclusions:
- Induced TACE-mediated shedding is, in part, due to increased enzymatic activity of TACE.
- The cytoplasmic domain of TACE is not essential for this induced activity.