Cellular signaling by an agonist-activated receptor/Gs alpha fusion protein.
The consequences of agonist-dependent activation of guanine nucleotide-binding protein (G protein)-coupled receptors vary from cell to cell, depending on a complex network of regulations between components of the signaling cascade. Specific interactions between receptors, G proteins, and effectors are difficult to analyze in intact cells. Engineering of receptor-transducer fusion proteins might be an effective strategy to target cellular effectors more efficiently and specifically. As a model, we evaluated the ability of a fusion protein of beta 2-adrenergic receptor bound to the alpha subunit of adenylyl cyclase-stimulatory G protein (Gs alpha) to restore the defective activation of adenylyl cyclase in S49 cyc- cells that lack endogenous Gs alpha. The coupling between the two partners of the fusion protein was functional, and the agonist-dependent activation of the effector was more potent and more productive in transfected than in wild-type S49 cells. The covalent link between receptor and Gs alpha could thus convey an advantage over freely interacting components. Such receptor-G alpha fusion proteins may help to elucidate the complex interactions between members of signaling pathways and may also constitute a useful tool for studying the effects of single effector activation.
Bertin
B
B
Institut Cochin de Génétique Moléculaire, Laboratoire d'Immunopharmacologie Moleculaire, Paris, France.
Freissmuth
M
M
Jockers
R
R
Strosberg
A D
AD
Marullo
S
S
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D051379:Mice; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D011993:Recombinant Fusion Proteins; D015398:Signal Transduction
D011943:Receptors, Adrenergic, beta; D011993:Recombinant Fusion Proteins; D002772:Cholera Toxin; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases; D007545:Isoproterenol