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Receptor selectivity between the G proteins Gα 12 and Gα 13 is defined by a single leucine‐to‐isoleucine variation
Author(s) -
Mackenzie Amanda E.,
Quon Tezz,
Lin LiChiung,
Hauser Alexander S.,
Jenkins Laura,
Inoue Asuka,
Tobin Andrew B.,
Gloriam David E.,
Hudson Brian D.,
Milligan Graeme
Publication year - 2019
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201801956r
Subject(s) - heterotrimeric g protein , leucine , isoleucine , g protein coupled receptor , g protein , chemistry , selectivity , amino acid , gq alpha subunit , receptor , biochemistry , catalysis
Despite recent advances in structural definition of GPCR–G protein complexes, the basis of receptor selectivity between G proteins remains unclear. The Gα 12 and Gα 13 subtypes together form the least studied group of heterotrimeric G proteins. G protein–coupled receptor 35 (GPR35) has been suggested to couple efficiently to Gα 13 but weakly to Gα 12 . Using combinations of cells genome‐edited to not express G proteins and bioluminescence resonance energy transfer–based sensors, we confirmed marked selectivity of GPR35 for Gα 13 . Incorporating Gα 12 /Gα 13 chimeras and individual residue swap mutations into these sensors defined that selectivity between Gα 13 and Gα 12 was imbued largely by a single leucine‐to‐isoleucine variation at position G.H5.23. Indeed, leucine could not be substituted by other amino acids in Gα 13 without almost complete loss of GPR35 coupling. The critical importance of leucine at G.H5.23 for GPR35–G protein interaction was further demonstrated by introduction of this leucine into Gα q , resulting in the gain of coupling to GPR35. These studies demonstrate that Gα 13 is markedly the most effective G protein for interaction with GPR35 and that selection between Gα 13 and Gα 12 is dictated largely by a single conservative amino acid variation.—Mackenzie, A. E., Quon, T., Lin, L.‐C., Hauser, A. S., Jenkins, L., Inoue, A., Tobin, A. B., Gloriam, D. E., Hudson, B. D., Milligan, G. Receptor selectivity between the G proteins Gα 12 and Gα 13 is defined by a single leucine‐to‐isoleucine variation. FASEB J. 33, 5005–5017 (2019). www.fasebj.org