Abstract
Previous studies have suggested that the interaction between the small adaptor protein Grb2 with the Ras guanyl nucleotide exchange factor SOS is functionally important in the regulation of the Ras activation/inactivation cycle. To examine the relationship between the Grb2-SOS complex and Ras activation, we observed that insulin stimulation results in a rapid but transient activation of Ras and the extracellular-signal regulated kinase (ERK) followed by dissociation of the Grb2-SOS complex. Although treatment with the phorbol myristate acetate resulted in ERK activation and complete dissociation of the Grb2-SOS complex, there was no effect on subsequent insulin-stimulated Ras activation. Similarly, insulin stimulation followed by insulin removal resulted in a time-dependent restoration of the Grb2-SOS complex but which was significantly slower than the recovery of insulin- stimulated Ras activation. In addition, although insulin was able to activate Ras under these conditions, there was a complete desensitization of Raf and ERK activation. This apparent homologous desensitization of insulin action was specific for Raf and ERK as the insulin re-stimulation of insulin receptor autophosphorylation and protein kinase B activation were unaffected. Together, these data demonstrate the presence of a pathway independent of the Grb2-SOS complex that can lead to Ras activation but that the desensitization of Raf accounts for the homologous desensitization of ERK.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 18651-18658 |
| Number of pages | 8 |
| Journal | Journal of Biological Chemistry |
| Volume | 274 |
| Issue number | 26 |
| DOIs | |
| State | Published - Jun 25 1999 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Insulin-induced desensitization of extracellular signal-regulated kinase activation results from an inhibition of Raf activity independent of Ras activation and dissociation of the Grb2-SOS complex. / Fucini, Raymond V.; Okada, Shuichi; Pessin, Jeffrey E.
In: Journal of Biological Chemistry, Vol. 274, No. 26, 25.06.1999, p. 18651-18658.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Insulin-induced desensitization of extracellular signal-regulated kinase activation results from an inhibition of Raf activity independent of Ras activation and dissociation of the Grb2-SOS complex
AU - Fucini, Raymond V.
AU - Okada, Shuichi
AU - Pessin, Jeffrey E.
PY - 1999/6/25
Y1 - 1999/6/25
N2 - Previous studies have suggested that the interaction between the small adaptor protein Grb2 with the Ras guanyl nucleotide exchange factor SOS is functionally important in the regulation of the Ras activation/inactivation cycle. To examine the relationship between the Grb2-SOS complex and Ras activation, we observed that insulin stimulation results in a rapid but transient activation of Ras and the extracellular-signal regulated kinase (ERK) followed by dissociation of the Grb2-SOS complex. Although treatment with the phorbol myristate acetate resulted in ERK activation and complete dissociation of the Grb2-SOS complex, there was no effect on subsequent insulin-stimulated Ras activation. Similarly, insulin stimulation followed by insulin removal resulted in a time-dependent restoration of the Grb2-SOS complex but which was significantly slower than the recovery of insulin- stimulated Ras activation. In addition, although insulin was able to activate Ras under these conditions, there was a complete desensitization of Raf and ERK activation. This apparent homologous desensitization of insulin action was specific for Raf and ERK as the insulin re-stimulation of insulin receptor autophosphorylation and protein kinase B activation were unaffected. Together, these data demonstrate the presence of a pathway independent of the Grb2-SOS complex that can lead to Ras activation but that the desensitization of Raf accounts for the homologous desensitization of ERK.
AB - Previous studies have suggested that the interaction between the small adaptor protein Grb2 with the Ras guanyl nucleotide exchange factor SOS is functionally important in the regulation of the Ras activation/inactivation cycle. To examine the relationship between the Grb2-SOS complex and Ras activation, we observed that insulin stimulation results in a rapid but transient activation of Ras and the extracellular-signal regulated kinase (ERK) followed by dissociation of the Grb2-SOS complex. Although treatment with the phorbol myristate acetate resulted in ERK activation and complete dissociation of the Grb2-SOS complex, there was no effect on subsequent insulin-stimulated Ras activation. Similarly, insulin stimulation followed by insulin removal resulted in a time-dependent restoration of the Grb2-SOS complex but which was significantly slower than the recovery of insulin- stimulated Ras activation. In addition, although insulin was able to activate Ras under these conditions, there was a complete desensitization of Raf and ERK activation. This apparent homologous desensitization of insulin action was specific for Raf and ERK as the insulin re-stimulation of insulin receptor autophosphorylation and protein kinase B activation were unaffected. Together, these data demonstrate the presence of a pathway independent of the Grb2-SOS complex that can lead to Ras activation but that the desensitization of Raf accounts for the homologous desensitization of ERK.
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U2 - 10.1074/jbc.274.26.18651
DO - 10.1074/jbc.274.26.18651
M3 - Article
VL - 274
SP - 18651
EP - 18658
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 26
ER -