Alpha 2 adrenergic receptor subtypes expressed in Chinese hamster ovary cells activate differentially mitogen-activated protein kinase by a p21ras independent pathway.
J Biol Chem
; 270(8): 3491-4, 1995 Feb 24.
Article
in En
| MEDLINE
| ID: mdl-7876081
ABSTRACT
Epinephrine stimulation of rat alpha 2D, alpha 2B, and alpha 2C adrenergic receptor subtypes, expressed stably in Chinese hamster ovary (CHO) cells, caused a rapid, transient activation of mitogen-activated protein kinase (MAPK), with subtype-specific different efficiencies. The order of activation was CHO-2B approximately CHO-2D much greater than CHO-2C. Pertussis toxin blocked the stimulation of MAPK enzymatic activity and the parallel MAPK phosphorylation, demonstrating that these responses are mediated by pertussis toxin-sensitive Gi proteins. Contrary to what has been reported for the alpha 2A subtype expressed in rat-1 fibroblasts, epinephrine did not cause any detectable activation of p21ras in the CHO transfectants. Furthermore, combined application of epinephrine and phorbol myristate acetate had a potent cooperative but not additive effect in clones CHO-2D and CHO-2B but not in CHO-2C, suggesting that protein kinase C is probably differently involved in the signaling by the three alpha 2 receptor subtypes. These results show that in CHO cells, the different alpha 2 adrenergic receptor subtypes utilize differential pathways to activate MAPK in a p21ras-independent way.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Protein Kinases
/
Oncogene Protein p21(ras)
/
Receptors, Adrenergic, alpha-2
Limits:
Animals
Language:
En
Journal:
J Biol Chem
Year:
1995
Document type:
Article
Affiliation country:
France