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Insulin processing and signal transduction in rat adipocytes
1Department of Biochemistry and Molecular Biology, School of Biological Sciences, University of Manchester, U.K.
Biochimica Et Biophysica Acta
|March 6, 1989
Summary
Insulin binding to adipocytes is followed by internalization and degradation. Inhibiting internalization or hormone-receptor uncoupling did not block glucose uptake, suggesting insulin degradation is not required for signal transduction.
Area of Science:
- Cell biology
- Endocrinology
- Biochemistry
Background:
- Insulin signaling is crucial for glucose homeostasis.
- Understanding insulin receptor dynamics and downstream effects is key to metabolic research.
Purpose of the Study:
- To investigate the role of insulin internalization and degradation in signal transduction.
- To determine if lysosomal degradation is necessary for insulin's effects on glucose uptake.
Main Methods:
- Utilized [125I]iodoinsulin to study insulin binding and internalization in adipocytes.
- Employed glycine-HCl buffer for receptor stripping and phenylarsine oxide (PAO) and monensin as inhibitors.
Main Results:
- Insulin binding at 37°C led to rapid internalization and degradation.
- PAO inhibited insulin degradation, while monensin restricted it temporarily, without affecting glucose uptake.
- PAO's transient inhibition of glucose uptake was observed, with subsequent recovery.
Conclusions:
- Lysosomal degradation of insulin is not essential for signal transduction.
- Insulin receptor internalization and hormone degradation are distinct processes from glucose uptake signaling.