Rapid internalization of the insulin receptor in rat hepatoma cells

Conference · Fri May 01 04:00:00 EDT 1987 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:6285671

Backer, J M; White, M F; Kahn, C R

The authors have studied the internalization of the insulin receptor (IR) in rat hepatoma cells (Fao). The cells were surface-iodinated at 4C, stimulated with insulin at 37C, and then cooled rapidly, trypsinized at 4C and solubilized. The IR was immunoprecipitated with a specific antibody, and internalization of the IR was assessed by the appearance of trypsin-resistant bands on SDS-PAGE. Insulin induced the internalization of surface receptors with a t 1/2 of 9-10 mins; cells not exposed to insulin internalized less than 20% of the IR during 1 h at 37C. Further experiments demonstrated that the accumulation of trypsin-resistant IR paralleled a loss of receptor from the cell surface. Insulin-stimulated cells were chilled and iodinated at 4C, followed by solubilization, immunoprecipitation and SDS-PAGE; alternatively, insulin-stimulated cells were chilled, surface-bound ligand removed by washing the cells at pH 4.2, and specific ( SVI)insulin binding measured at 4C. Both techniques confirmed the disappearance of IR from the cell surface at rates comparable to the insulin-stimulated internalization described above. The total amount of phosphotyrosine-containing IR, as assessed by immunoprecipitation with an anti-phosphotyrosine antibody, remained constant during this time interval, suggesting that active kinase is translocated into the cell. In summary, the authors data indicate that insulin binding increases the rate of IR internalization of Fao cells. This relocation may facilitate the interaction of the activated tyrosine kinase in the IR with intracellular substrates, thus transmitting the insulin signal to metabolic pathways.

• Research Organization: Joslin Diabetes Center, Boston, MA
• OSTI ID: 6285671
• Report Number(s): CONF-870644-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 46:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL PATHWAYS
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENZYMES
HEPATOMAS
HORMONES
HYDROXY ACIDS
INSULIN
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGANDS
MAMMALS
NEOPLASMS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
TRACER TECHNIQUES
TRANSFERASES
TUMOR CELLS
TYROSINE
VERTEBRATES