Recycling of photoaffinity-labeled insulin receptors in rat adipocytes. Dissociation of insulin-receptor complexes is not required for receptor recycling

Journal Article · Sat Jul 05 04:00:00 EDT 1986 · J. Biol. Chem.; (United States)

OSTI ID:5127509

Huecksteadt, T; Olefsky, J M; Brandenberg, D; Heidenreich, K A

We have used an iodinated, photoreactive analog of insulin, /sup 125/I-B2(2-nitro-4-azidophenylacetyl)-des-PheB1-insulin, to covalently label insulin receptors on the cell surface of isolated rat adipocytes. Following internalization of the labeled insulin-receptor complexes at 37/sup 0/C, we measured the rate and extent of recycling of these complexes using trypsin to distinguish receptors on the cell surface from those inside the cell. The return of internalized photoaffinity-labeled receptors to the cell surface was very rapid at 37/sup 0/C proceeding with an apparent t 1/2 of 6 min. About 95% of the labeled receptors present in the cell 20 min after the initiation of endocytosis returned to the cell surface by 40 min. Recycling was slower at 25 and 16/sup 0/C compared to 37/sup 0/C and essentially negligible at 12/sup 0/C or in the presence of energy depleters. Addition of excess unlabeled insulin had no effect on the recycling of photoaffinity-labeled insulin receptor complexes, whereas monensin, chloroquine, and Tris partially inhibited this process. These data indicate that dissociation of insulin from internalized receptors is not necessary for insulin receptor recycling. Furthermore, agents which have been shown to prevent vesicular acidification inhibit the recycling of insulin receptors by a mechanism other than prevention of ligand dissociation.

• OSTI ID: 5127509
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 19; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADIPOSE TISSUE
ANIMAL TISSUES
ANIMALS
AZIDES
BETA DECAY RADIOISOTOPES
BODY
CHEMICAL REACTIONS
CONNECTIVE TISSUE
DAYS LIVING RADIOISOTOPES
DECOMPOSITION
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
HORMONES
HYDROLASES
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
MOLECULAR WEIGHT
NITROGEN COMPOUNDS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PEPTIDE HYDROLASES
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
SERINE PROTEINASES
THERMODYNAMICS
TISSUES
TRACER TECHNIQUES
TRYPSIN
VERTEBRATES