Gαノックアウト細胞で切り分けたGPCRシグナル～“特異的”と信じられてきた転写レポーターの再定義～

2026-02-10

2026-02-10 京都大学

齋藤郁貴薬学研究科博士課程学生、木瀬亮次同助教、井上飛鳥同教授(兼:東北大学教授)の研究グループは、Gタンパク質共役型受容体(GPCR)シグナルにおけるGαタンパク質と転写応答配列の関係を、CRISPR-Cas9法で内因性Gαタンパク質を個別に欠損させたノックアウト細胞を用いて網羅的に解析した。従来、特定の転写レポーターは特定のGαサブファミリーに対応すると考えられてきたが、本解析によりその対応関係は想定以上に多様であることが明らかとなった。これにより、“特異的”と信じられてきた転写レポーターの解釈が再定義され、GPCRを介した転写活性評価の精度向上が期待される。本成果は、GPCRシグナル解析の基盤理解を深め、創薬研究に新たな指針を与えるものである。

本研究で明らかにしたGαタンパク質と転写応答配列の新たな対応関係

<関連情報>

GPCRシグナル伝達におけるGαタンパク質-応答要素特異性の再評価
Re-evaluating Gα protein–response element specificity in GPCR signaling

Ayaki Saito,Ryoji Kise,So Yamaguchi,Masataka Yanagawa & Asuka Inoue
Communications Biology Published:23 January 2026
DOI:https://doi.org/10.1038/s42003-026-09569-z An unedited version of this manuscript

Reporter gene assays are widely employed to investigate activation of G-protein-coupled receptors (GPCRs). However, the increasing complexity of GPCR signaling—particularly the capability of many receptors to couple with multiple Gα subunits—has created a growing need for reliable methods to dissect individual Gα-mediated pathways. Recent insights into the crosstalk and interdependence among Gα subfamilies have further complicated our understanding of the overarching GPCR signaling landscape. While previous studies have linked specific Gα-proteins to distinct transcriptional response elements, the precise specificity of these associations remains unclear. Here, we systematically identified the relationship between Gα proteins and four commonly used GPCR-regulated response elements—CRE, SRE, NFAT-RE, and SRF-RE—using a panel of Gα knockout (KO) cell lines. Contrary to the traditional model of near-exclusive Gα–response element pairings, our results reveal that each reporter is modulated by multiple Gα subfamilies. Each response element exhibited varying degrees of activation by different Gα proteins, with CRE being predominantly regulated by Gα_s/olf, and SRE, NFAT-RE, and SRF-RE primarily regulated by Gα_q/11. Based on these results, we provide an updated framework that redefines the subfamily-specific Gα regulation of downstream transcriptional responses and underscores the need for caution when interpreting reporter assays to assess Gα-protein activity.