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Homogeneous Time-resolved Förster Resonance Energy Transfer-based Assay for Detection of Insulin Secretion
Published on: May 10, 2018
Insulin-degrading enzyme does not require peroxisomal localization for insulin degradation
V Chesneau1, R K Perlman, W Li
1Ben May Institute for Cancer Research, The University of Chicago, Illinois 60637, USA.
Endocrinology
|August 1, 1997
Summary
Insulin-degrading enzyme (IDE) does not require peroxisomal localization for insulin degradation. Mutations affecting its peroxisomal targeting signal did not impair insulin degradation, suggesting multiple cellular roles for IDE.
Area of Science:
- Biochemistry
- Cell Biology
- Enzymology
Background:
- Insulin-degrading enzyme (IDE) is implicated in insulin metabolism.
- The precise mechanism and cellular site of IDE action remain unclear.
Purpose of the Study:
- To investigate the role of peroxisomal localization in IDE's insulin degradation activity.
- To examine the necessity of the peroxisomal targeting signal (PTS) for IDE function.
Main Methods:
- Site-directed mutagenesis of the human IDE PTS (A/S-K-L tripeptide).
- Expression of wild-type and mutant IDE in COS cells.
- Analysis of protein size, immunoreactivity, insulin binding, in vitro activity, and cellular insulin degradation.
- Immunocytofluorescence to determine subcellular localization.
Main Results:
- Mutations altering the PTS (AL.pts, LV.pts) did not affect IDE's size, binding, activity, or insulin degradation.
- A deletion mutant (DEL.pts) resulted in a shorter protein unable to bind insulin.
- Wild-type IDE localized to peroxisomes, but PTS mutants did not.
- IDE does not require peroxisomal localization for insulin degradation.
Conclusions:
- The carboxy-terminal tripeptide is important for IDE stability but not essential for insulin degradation.
- Peroxisomal localization is not required for IDE's insulin-degrading function.
- IDE likely possesses multiple cellular functions beyond insulin metabolism.
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