Tyrosine kinase-defective insulin receptors undergo insulin-induced microaggregation but do not concentrate in coated pits.
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چکیده
منابع مشابه
Tyrosine kinase-defective insulin receptors undergo insulin-induced microaggregation but do not concentrate in coated pits.
Biologically active colloid-gold complexes were used to compare ligand-induced microaggregation, redistribution, and internalization of insulin receptors on Rat 1 fibroblasts expressing wild type (HIRc) or tyrosine kinase-defective (HIR A/K1018) human insulin receptors. Insulin-like growth factor I (IGF I) and alpha 2-macroglobulin receptors also were compared. On both cell types, all four unoc...
متن کاملA mutant insulin receptor with defective tyrosine kinase displays no biologic activity and does not undergo endocytosis.
The cDNAs encoding the normal human insulin receptor (HIRc) and a receptor that had lysine residue 1018 replaced by alanine (A/K1018) were used to transfect Rat 1 fibroblasts. Lysine 1018 is a critical residue in the ATP binding site of the tyrosine kinase domain in the receptor beta-subunit. Untransfected Rat 1 cells express 1700 endogenous insulin receptors. Expressed HIRc receptors had level...
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Insulin receptors from chicken liver and brain were studied following alterations in the nutritional state. Chickens were either fasted for 48 h, fasted for 48 h and then refed for 24 h, or fed a regular diet ad libitum. 125I-Porcine insulin binding was significantly elevated in liver membranes from the fasted animals and lowered in refed chickens when compared to preparations from ad libitum f...
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The internalization and degradation of insulin was assessed in Chinese hamster ovary cell lines expressing either the wild-type receptor or mutated receptors lacking kinase activity. The mutated receptors included receptors which differed from the wild-type receptor by a single amino acid (substitution of an arginine for lysine at position 1030, a site critical for ATP binding) as well as recep...
متن کاملRecruitment of Epidermal Growth Factor Receptors into Coated Pits Requires Their Activated Tyrosine Kinase
EGF-receptor (EGF-R) tyrosine kinase is required for the down-regulation of activated EGF-R. However, controversy exists as to whether ligandinduced activation of the EGF-R tyrosine kinase is required for internalization or for lysosomal targeting. We have addressed this issue using a cell-free assay that selectively measures the recruitment of EGF-R into coated pits. Here we show that EGF boun...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1991
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(19)47403-6