Publications
대표논문
Date: March 2, 1999

Journal: Journal of Biological Chemistry Volume 274, Issue 21, 21 May 1999, Pages 14963-14971 , Doi: 10.1074/jbc.274.21.14963

1999 | Two amino acids within the helix of Gα(i1) mediate coupling with 5- hydroxytryptamine(1B) receptors…

Hyunsu Bae, Theresa M. Cabrera-Vera, Karyn M. Depree, Stephen G. Graber and Heidi E. Hamm

Abstract

We previously reported that residues 299–318 in Gαi1 participate in the selective interaction between Gαi1 and the 5-hydroxytryptamine1B(5-HT1B) receptor (Bae, H., Anderson, K., Flood, L. A., Skiba, N. P., Hamm, H. E., and Graber, S. G. (1997)J. Biol. Chem. 272, 32071–32077). The present study more precisely defines which residues within this domain are critical for 5-HT1B receptor-mediated G protein activation. A series of Gαi1/Gαt chimeras and point mutations were reconstituted with Gβγ and Sf9 cell membranes containing the 5-HT1B receptor. Functional coupling to 5-HT1B receptors was assessed by 1) [35S]GTPγS binding and 2) agonist affinity shift assays. Replacement of the α4 helix of Gαi1 (residues 299–308) with the corresponding sequence from Gαtproduced a chimera (Chi22) that only weakly coupled to the 5-HT1B receptor. In contrast, substitution of residues within the α4-β6 loop region of Gαi1 (residues 309–318) with the corresponding sequence in Gαt either permitted full 5-HT1B receptor coupling to the chimera (Chi24) or only minimally reduced coupling to the chimeric protein (Chi25). Two mutations within the α4 helix of Gαi1 (Q304K and E308L) reduced agonist-stimulated [35S]GTPγS binding, and the effects of these mutations were additive. The opposite substitutions within Chi22 (K300Q and L304E) restored 5-HT1B receptor coupling, and again the effects of the two mutations were additive. Mutations of other residues within the α4 helix of Gαi1 had minimal to no effect on 5-HT1B coupling behavior. These data provide evidence that α4 helix residues in Gαi participate in directing specific receptor interactions and suggest that Gln304 and Glu308 of Gαi1 act in concert to mediate the ability of the 5-HT1B receptor to couple specifically to inhibitory G proteins.  


TITLE
 Two amino acids within the helix of Gα(i1) mediate coupling with 5- hydroxytryptamine(1B) receptors
JOURNAL
 Journal of Biological Chemistry
 Volume 274, Issue 21, 21 May 1999, Pages 14963-14971
 DOI
 10.1074/jbc.274.21.14963 (click 하시면 DOI 검색 결과가 새창으로 나타납니다.)
 
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Publications

대표논문




2000 ~ 2014