Abstract
To examine the role of intramolecular β subunit trans- and cis-autophosphorylation in signal transduction, the vaccinia virus/bacteriophage T7 expression system was used to generate insulin holoreceptors composed of a kinase-defective half-receptor precursor (αβA/K or αβA/K.ΔCT) and a kinase-active half-receptor precursor (αβΔCT or αβWT). In the αβWT-αβΔCT hybrid insulin receptor, insulin stimulated a 20-fold increase in intramolecular β subunit trans-phosphorylation, whereas cis-phosphorylation increased only 3-fold over the basal state. Similarly, in the αβWT-αβA/K.ΔCT hybrid insulin receptor, insulin stimulated trans-phosphorylation approximately 30-fold and cis-phosphorylation only 3-fold over the basal state. Although cis-phosphorylation of the kinase-functional αβ half-receptor was observed within these hybrid receptor species, this was not sufficient to stimulate exogenous substrate kinase activity. These data demonstrate that insulin primarily activates an intramolecular β subunit trans-phosphorylation reaction within the insulin holoreceptor and suggest that this reaction is necessary for activation of the holoreceptor. Furthermore, our results suggest a molecular basis for the dominant-negative phenotype observed in insulin-resistant patients possessing one kinase-defective insulin receptor allele.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 19521-19528 |
| Number of pages | 8 |
| Journal | Journal of Biological Chemistry |
| Volume | 267 |
| Issue number | 27 |
| State | Published - Sep 25 1992 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Transmembrane signaling by the human insulin receptor kinase : Relationship between intramolecular β subunit trans- and cis-autophosphorylation and substrate kinase activation. / Frattali, Anne L.; Treadway, Judith L.; Pessin, Jeffrey E.
In: Journal of Biological Chemistry, Vol. 267, No. 27, 25.09.1992, p. 19521-19528.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Transmembrane signaling by the human insulin receptor kinase
T2 - Relationship between intramolecular β subunit trans- and cis-autophosphorylation and substrate kinase activation
AU - Frattali, Anne L.
AU - Treadway, Judith L.
AU - Pessin, Jeffrey E.
PY - 1992/9/25
Y1 - 1992/9/25
N2 - To examine the role of intramolecular β subunit trans- and cis-autophosphorylation in signal transduction, the vaccinia virus/bacteriophage T7 expression system was used to generate insulin holoreceptors composed of a kinase-defective half-receptor precursor (αβA/K or αβA/K.ΔCT) and a kinase-active half-receptor precursor (αβΔCT or αβWT). In the αβWT-αβΔCT hybrid insulin receptor, insulin stimulated a 20-fold increase in intramolecular β subunit trans-phosphorylation, whereas cis-phosphorylation increased only 3-fold over the basal state. Similarly, in the αβWT-αβA/K.ΔCT hybrid insulin receptor, insulin stimulated trans-phosphorylation approximately 30-fold and cis-phosphorylation only 3-fold over the basal state. Although cis-phosphorylation of the kinase-functional αβ half-receptor was observed within these hybrid receptor species, this was not sufficient to stimulate exogenous substrate kinase activity. These data demonstrate that insulin primarily activates an intramolecular β subunit trans-phosphorylation reaction within the insulin holoreceptor and suggest that this reaction is necessary for activation of the holoreceptor. Furthermore, our results suggest a molecular basis for the dominant-negative phenotype observed in insulin-resistant patients possessing one kinase-defective insulin receptor allele.
AB - To examine the role of intramolecular β subunit trans- and cis-autophosphorylation in signal transduction, the vaccinia virus/bacteriophage T7 expression system was used to generate insulin holoreceptors composed of a kinase-defective half-receptor precursor (αβA/K or αβA/K.ΔCT) and a kinase-active half-receptor precursor (αβΔCT or αβWT). In the αβWT-αβΔCT hybrid insulin receptor, insulin stimulated a 20-fold increase in intramolecular β subunit trans-phosphorylation, whereas cis-phosphorylation increased only 3-fold over the basal state. Similarly, in the αβWT-αβA/K.ΔCT hybrid insulin receptor, insulin stimulated trans-phosphorylation approximately 30-fold and cis-phosphorylation only 3-fold over the basal state. Although cis-phosphorylation of the kinase-functional αβ half-receptor was observed within these hybrid receptor species, this was not sufficient to stimulate exogenous substrate kinase activity. These data demonstrate that insulin primarily activates an intramolecular β subunit trans-phosphorylation reaction within the insulin holoreceptor and suggest that this reaction is necessary for activation of the holoreceptor. Furthermore, our results suggest a molecular basis for the dominant-negative phenotype observed in insulin-resistant patients possessing one kinase-defective insulin receptor allele.
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M3 - Article
C2 - 1326556
AN - SCOPUS:0026649556
VL - 267
SP - 19521
EP - 19528
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 27
ER -