Interaction of 14-3-3 protein with regulator of G protein signaling 7 is dynamically regulated by tumor necrosis factor-alpha.
Regulators of G protein signaling (RGS) constitute a family of proteins with a conserved RGS domain of approximately 120 amino acids that accelerate the intrinsic GTP hydrolysis of activated Galpha(i) and Galpha(q) subunits. The phosphorylation-dependent interaction of 14-3-3 proteins with a subset of RGS proteins inhibits their GTPase-accelerating activity in vitro. The inhibitory interaction between 14-3-3 and RGS7 requires phosphorylation of serine 434 of RGS7. We now show that phosphorylation of serine 434 is dynamically regulated by TNF-alpha. Cellular stimulation by TNF-alpha transiently decreased the phosphorylation of serine 434 of RGS7, abrogating the inhibitory interaction with 14-3-3. We examined the effect of 14-3-3 on RGS-mediated deactivation kinetics of G protein-coupled inwardly rectifying K(+) channels (GIRKs) in Xenopus oocytes. 14-3-3 inhibited the function of wild-type RGS7, but not that of either RSG7(P436R) or RGS4, two proteins that do not bind 14-3-3. Our findings are the first evidence that extracellular signals can modulate the activity of RGS proteins by regulating their interaction with 14-3-3.
Benzing
Thomas
T
Renal Division and Center for Clinical Research, University Hospital Freiburg, Hugstetterstrasse 55, 79106 Freiburg, Germany.
Köttgen
Michael
M
Johnson
Marc
M
Schermer
Bernhard
B
Zentgraf
Hanswalter
H
Walz
Gerd
G
Kim
Emily
E
D048948:14-3-3 Proteins; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D010766:Phosphorylation; D010768:Phosphoserine / Q000737:chemistry; D011188:Potassium / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020710:RGS Proteins / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D014982:Xenopus laevis
D048948:14-3-3 Proteins; D020710:RGS Proteins; C492039:RGS7 protein, human; C492038:Rgs7 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D010768:Phosphoserine; D012694:Serine; D014446:Tyrosine 3-Monooxygenase; D019204:GTP-Binding Proteins; D011188:Potassium