Decreased autophosphorylation of EGF receptor in insulin-deficient diabetic rats
- Harvard Medical School, Boton, MA (USA)
The authors have previously reported that despite an increase in receptor concentration, there is a decrease in autophosphorylation and tyrosine kinase activity of the insulin receptor in insulin-deficient diabetic rats. To determine if other tyrosine kinases might be altered, they have studied the epidermal growth factor (EGF) receptor kinase in wheat germ agglutinin-purified, Triton X-100-solubilized liver membranes from streptozotocin (STZ)-induced diabetic rats and the insulin-deficient BB rat. They find that autophosphorylation of EGF receptor is decreased in proportion to the severity of the diabetic state in STZ rats with a maximal decrease of 67%. A similar decrease in autophosphorylation was observed in diabetic BB rats that was partially normalized by insulin treatment. Separation of tryptic phosphopeptides by reverse-phase high-performance liquid chromatography revealed a decrease in labeling at all sites of autophosphorylation. A parallel decrease in EGF receptor phosphorylation was also found by immunoblotting with an antiphosphotyrosine antibody. EGF receptor concentration, determined by Scatchard analysis of {sup 125}I-labeled EGF binding, was decreased by 39% in the STZ rat and 27% in the diabetic BB rat. Thus autophosphorylation of EGF receptor, like that of the insulin receptor, is decreased in insulin-deficient rat liver. In the case of EGF receptor, this is due in part to a decrease in receptor number and in part to a decrease in the specific activity of the kinase.
- OSTI ID:
- 6746956
- Journal Information:
- American Journal of Physiology; (USA), Vol. 254:4; ISSN 0002-9513
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
DIABETES MELLITUS
PATHOGENESIS
GROWTH FACTORS
RADIORECEPTOR ASSAY
MEMBRANE PROTEINS
AUTORADIOGRAPHY
RECEPTORS
PHOSPHORYLATION
ANTIBODIES
ATP
DOSE-RESPONSE RELATIONSHIPS
INSULIN
IODINE 125
LIVER CELLS
PHOSPHORUS 32
PHOSPHOTRANSFERASES
RATS
TYROSINE
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE DISEASES
ENZYMES
HORMONES
HYDROXY ACIDS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAMMALS
METABOLIC DISEASES
MITOGENS
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PHOSPHORUS ISOTOPES
PHOSPHORUS-GROUP TRANSFERASES
PROTEINS
RADIOISOTOPES
RODENTS
SOMATIC CELLS
TRACER TECHNIQUES
TRANSFERASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques