Abstract
Numerous studies have attested to the importance of the extreme C terminus of G protein α subunits in determining their selectivity of receptor recognition. We have previously reported that a highly conserved glycine residue within linker I is important for constraining the fidelity of receptor recognition by Gαq proteins. Herein, we explored whether both modules (linker I and extreme C terminus) interact cooperatively in switching G protein-coupled receptor (GPCR)-to-effector specificity and created as models mutant Gαq proteins in which glycine was replaced with various amino acids and the C-terminal five Gαq residues with the corresponding Gαi or Gαs sequence. Coupling properties of the mutated Gαq proteins were determined after coexpression with a panel of 13 Gi-and Gs-selective receptors and compared with those of Gα proteins modified in only one module. Gα proteins modified in both modules are significantly more efficacious in channeling non-Gq-selective receptors to G q-mediated signaling events compared with those containing each module alone. Additive effects of both modules were observed even if individual modules lacked an effect on GPCR-to-effector specificity. Dually modified Gα proteins were also superior in conferring high-affinity agonist sites onto a coexpressed GPCR in the absence, but not in the presence, of guanine nucleotides. Together, our data suggest that receptor-G protein coupling selectivity involves cooperative interactions between the extreme C terminus and linker I of Gα proteins and that distinct determinants of selectivity exist for individual receptors.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 78-87 |
| Number of pages | 10 |
| Journal | Journal of Pharmacology and Experimental Therapeutics |
| Volume | 313 |
| Issue number | 1 |
| DOIs | |
| State | Published - Apr 1 2005 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Molecular Medicine
- Pharmacology
Cite this
A highly conserved glycine within linker I and the extreme C terminus of G protein α subunits interact cooperatively in switching G protein-coupled receptor-to-effector specificity. / Kostenis, Evi; Martini, Lene; Ellis, James; Waldhoer, Maria; Heydorn, Arne; Rosenkilde, Mette M.; Norregaard, Pia K.; Jorgensen, Rasmus; Whistler, Jennifer; Milligan, Graeme.
In: Journal of Pharmacology and Experimental Therapeutics, Vol. 313, No. 1, 01.04.2005, p. 78-87.Research output: Contribution to journal › Article
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TY - JOUR
T1 - A highly conserved glycine within linker I and the extreme C terminus of G protein α subunits interact cooperatively in switching G protein-coupled receptor-to-effector specificity
AU - Kostenis, Evi
AU - Martini, Lene
AU - Ellis, James
AU - Waldhoer, Maria
AU - Heydorn, Arne
AU - Rosenkilde, Mette M.
AU - Norregaard, Pia K.
AU - Jorgensen, Rasmus
AU - Whistler, Jennifer
AU - Milligan, Graeme
PY - 2005/4/1
Y1 - 2005/4/1
N2 - Numerous studies have attested to the importance of the extreme C terminus of G protein α subunits in determining their selectivity of receptor recognition. We have previously reported that a highly conserved glycine residue within linker I is important for constraining the fidelity of receptor recognition by Gαq proteins. Herein, we explored whether both modules (linker I and extreme C terminus) interact cooperatively in switching G protein-coupled receptor (GPCR)-to-effector specificity and created as models mutant Gαq proteins in which glycine was replaced with various amino acids and the C-terminal five Gαq residues with the corresponding Gαi or Gαs sequence. Coupling properties of the mutated Gαq proteins were determined after coexpression with a panel of 13 Gi-and Gs-selective receptors and compared with those of Gα proteins modified in only one module. Gα proteins modified in both modules are significantly more efficacious in channeling non-Gq-selective receptors to G q-mediated signaling events compared with those containing each module alone. Additive effects of both modules were observed even if individual modules lacked an effect on GPCR-to-effector specificity. Dually modified Gα proteins were also superior in conferring high-affinity agonist sites onto a coexpressed GPCR in the absence, but not in the presence, of guanine nucleotides. Together, our data suggest that receptor-G protein coupling selectivity involves cooperative interactions between the extreme C terminus and linker I of Gα proteins and that distinct determinants of selectivity exist for individual receptors.
AB - Numerous studies have attested to the importance of the extreme C terminus of G protein α subunits in determining their selectivity of receptor recognition. We have previously reported that a highly conserved glycine residue within linker I is important for constraining the fidelity of receptor recognition by Gαq proteins. Herein, we explored whether both modules (linker I and extreme C terminus) interact cooperatively in switching G protein-coupled receptor (GPCR)-to-effector specificity and created as models mutant Gαq proteins in which glycine was replaced with various amino acids and the C-terminal five Gαq residues with the corresponding Gαi or Gαs sequence. Coupling properties of the mutated Gαq proteins were determined after coexpression with a panel of 13 Gi-and Gs-selective receptors and compared with those of Gα proteins modified in only one module. Gα proteins modified in both modules are significantly more efficacious in channeling non-Gq-selective receptors to G q-mediated signaling events compared with those containing each module alone. Additive effects of both modules were observed even if individual modules lacked an effect on GPCR-to-effector specificity. Dually modified Gα proteins were also superior in conferring high-affinity agonist sites onto a coexpressed GPCR in the absence, but not in the presence, of guanine nucleotides. Together, our data suggest that receptor-G protein coupling selectivity involves cooperative interactions between the extreme C terminus and linker I of Gα proteins and that distinct determinants of selectivity exist for individual receptors.
UR - http://www.scopus.com/inward/record.url?scp=20144371840&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=20144371840&partnerID=8YFLogxK
U2 - 10.1124/jpet.104.080424
DO - 10.1124/jpet.104.080424
M3 - Article
C2 - 15615862
AN - SCOPUS:20144371840
VL - 313
SP - 78
EP - 87
JO - Journal of Pharmacology and Experimental Therapeutics
JF - Journal of Pharmacology and Experimental Therapeutics
SN - 0022-3565
IS - 1
ER -