Insulin-induced internalization of the insulin receptor in the isolated rat adipose cell. Detection of the internalized 138-kilodalton receptor subunit using a photoaffinity 125I-insulin.

摘要: A photoactive insulin analogue (N epsilon-B29-(2-nitro-4-azidophenylacetyl)insulin) which specifically and covalently labels the 138-kDa receptor subunit, is used here to examine effect of on subcellular distribution receptors in isolated rat adipose cell. The photolabeled subunit plasma Golgi-enriched membrane fractions was quantitated by Na dodecyl sulfate-polyacrylamide gel electrophoresis autoradiography. When intact cells are photolabeled, subsequent incubation for 30 min at 37 degrees C with saturating native induces a 30% loss labeled from fraction. Greater than 50% lost subunits can be recovered Qualitatively quantitatively similar results obtained when following their preparation. However, fraction only vesicles this made permeable presence 0.01% digitonin. appearance rapid, half-time 2 min, achieves steady state within 10 min. This also concentration-dependent, half-maximal maximal effects 6 nM, respectively, markedly, but not completely, inhibited 16 C. These suggest that rapid concentration- temperature-dependent translocation its own an intracellular cell, represents internalization through endocytic like process.