Insulin has both short- and long-term effects on cellular metabolism. The short-term effects are known to involve the insulin receptor, a protein kinase capable of phosphorylating itself and other proteins. The role of the receptor was elucidated by studies of a mutant insulin receptor which lacked
Photoaffinity labeling of the insulin receptor in H4 hepatoma cells: Lack of cellular receptor processing
✍ Scribed by Hofmann, Cecilia ;Ji, Tae H. ;Miller, Bonnie ;Steiner, Donald F.
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1981
- Tongue
- English
- Weight
- 811 KB
- Volume
- 15
- Category
- Article
- ISSN
- 0275-3723
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Photoaffinity labeling techniques were used to identify insulin‐binding components of the plasma membrane in insulin‐responsive, monolayer‐cultured hepatoma cells. The activated, photosensitive reagent, an n‐hydroxysuccinimide ester of 4‐azidobenzoic acid, was coupled with highly purifed insulin, and the hormone derivative was subsequently iodinated, bound to cell surface receptors of intact H4 cells, and photoactivatcd. After dissolution of the cells, labeled proteins were analyzed by SDS/polyacrylamide gel electrophoresis under reducing conditions. The main labeled band exhibited an apparent molecular weight of 130,000. Two minor components of apparent mol wt 95,000 and 40,000 were also identified. Specific labeling of all 3 bands was inhibited by simultaneous incubation of the cells with native insulin, but not by the heterologous hormone, glucagon, prior to photoactivation. Binding of azidobenzoyl‐insulin to H4 cells was time‐dependent, as was the correlated labeling of receptor components. Band‐labeling by the photosensitive insulin derivative was totally light‐dependent; spontaneous covalent linking of insulin and receptor was not observed. The labeled receptor‐related proteins were not degraded by the cells under our experimental conditions.
📜 SIMILAR VOLUMES
The binding of 'L51-insulin to primary cultures of bovine brain microvessel endothlial cells was examined. Insulin binding was both time and temperature dependent and inhibited by excess unlabeled insulin. Furthermore, the specific binding of insulin was polarized to the apical side of the cell mono
Histamine has been regarded as an inflammatory mediator of arthritic disorders. We have previously reported that the expression of histamine H 4 receptor (H 4 R) mRNA in synovial tissues was significantly higher in patients with osteoarthritis (OA) compared to those with rheumatoid arthritis. Chondr
A sensitive RIA was used to examine regulation of IGFBP-1 in H411E rat hepatoma cells. IGFBP-1 was stimulated up to tenfold by dexamethasone and corticosterone, and this stimulation was abolished by RU486. The effect of dexamethasone increased with time in culture. Phorbol 12-myristate 13-acetate (P