TYROSINE KINASE-ACTIVITY OF A CHIMERIC INSULIN-LIKE-GROWTH-FACTOR-1 RECEPTOR-CONTAINING THE INSULIN-RECEPTOR C-TERMINAL DOMAIN - COMPARISONWITH THE TYROSINE KINASE-ACTIVITIES OF THE INSULIN AND INSULIN-LIKE-GROWTH-FACTOR-1 RECEPTORS USING A CELL-FREE SYSTEM

Citation
I. Mothe et al., TYROSINE KINASE-ACTIVITY OF A CHIMERIC INSULIN-LIKE-GROWTH-FACTOR-1 RECEPTOR-CONTAINING THE INSULIN-RECEPTOR C-TERMINAL DOMAIN - COMPARISONWITH THE TYROSINE KINASE-ACTIVITIES OF THE INSULIN AND INSULIN-LIKE-GROWTH-FACTOR-1 RECEPTORS USING A CELL-FREE SYSTEM, European journal of biochemistry, 228(3), 1995, pp. 842-848
Citations number
25
Categorie Soggetti
Biology
ISSN journal
00142956
Volume
228
Issue
3
Year of publication
1995
Pages
842 - 848
Database
ISI
SICI code
0014-2956(1995)228:3<842:TKOACI>2.0.ZU;2-A
Abstract
In a previous study, we showed that a chimeric insulin-like-growth-fac tor-l (IGF-1) receptor, with the beta subunit C-terminal part of the i nsulin receptor was more efficient in stimulating glycogen synthesis a nd p44(mapk) activity compared to the wild-type IFG-1 receptor [Tartar e, S., Mothe, I., Kowalski-Chauvel, A., Breittmayer, J.-P., Ballotti, R. and Van Obberghen, E. (1994) J. Biol. Chem. 269, 11449-11455]. Thes e data indicate that the receptor C-terminal domain plays an important role in the transmission of biological effects. To understand the mol ecular basis of the differences in receptor specificity, we studied th e characteristics of insulin, IGF-1 and chimeric receptor tyrosine kin ase activities in a cell-free system. We found that, compared to wild- type insulin and IGF-1 receptors, the chimeric receptor showed a decre ase in (a) autophosphorylation, (b) tyrosine kinase activity towards i nsulin receptor substrate-1 and the insulin receptor-(1142-1158)-pepti de, and (c) the ability to activate phosphatidylinositol 3-kinase. How ever, for all the effects measured in a cell-free system, the chimeric receptor displayed an increased response td IGF-1 compared to the nat ive IGF-1 receptor. Concerning the cation dependence of the tyrosine k inase activity, we showed that, at 10 mM Mg2+, the Ligand-stimulated p hosphorylation of poly(Glu(80)Tyr(20)) by both insulin receptor and ch imeric receptor was increased by Mn2+. Conversely at 50 mM Mg2+, the c himeric receptor behaved like the IGF-1 receptor, since the presence o f Mn2+ decreased the stimulatory effect of IGF-1 on their kinase activ ity. Furthermore, the K-m of the chimeric receptor for ATP was increas ed compared to the wild-type receptors. These data demonstrate that th e replacement of the C-ter,oma; tail of the IGF-1 receptor by that of the insulin receptor has changed the receptor characteristics studied in a cell-free system. Our findings indicate that the C-terminal domai n of the insulin receptor beta subunit plays a key role in regulation of the tyrosine kinase activity. The fine-tuning of the tyrosine kinas e by the C-terminal tail could participate in the receptor specificity .