Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, 48109, USA.
Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
J Membr Biol. 2021 Jun;254(3):259-271. doi: 10.1007/s00232-020-00158-7. Epub 2020 Nov 24.
G protein-coupled receptors (GPCRs) are integral membrane proteins that transduce a wide array of inputs including light, ions, hormones, and neurotransmitters into intracellular signaling responses which underlie complex processes ranging from vision to learning and memory. Although traditionally thought to signal primarily from the cell surface, GPCRs are increasingly being recognized as capable of signaling from intracellular membrane compartments, including endosomes, the Golgi apparatus, and nuclear membranes. Remarkably, GPCR signaling from these membranes produces functional effects that are distinct from signaling from the plasma membrane, even though often the same G protein effectors and second messengers are activated. In this review, we will discuss the emerging idea of a "spatial bias" in signaling. We will present the evidence for GPCR signaling through G protein effectors from intracellular membranes, and the ways in which this signaling differs from canonical plasma membrane signaling with important implications for physiology and pharmacology. We also highlight the potential mechanisms underlying spatial bias of GPCR signaling, including how intracellular membranes and their associated lipids and proteins affect GPCR activity and signaling.
G 蛋白偶联受体(GPCRs)是整合膜蛋白,可将包括光、离子、激素和神经递质在内的各种输入转导为细胞内信号反应,这些反应是从视觉到学习和记忆等复杂过程的基础。尽管传统上认为 GPCR 主要从细胞表面发出信号,但越来越多的证据表明它们能够从细胞内膜区室(包括内体、高尔基体和核膜)发出信号。值得注意的是,即使经常激活相同的 G 蛋白效应器和第二信使,这些膜中的 GPCR 信号转导也会产生与质膜信号转导不同的功能效应。在这篇综述中,我们将讨论信号转导中出现的“空间偏向”这一新兴概念。我们将介绍 GPCR 通过细胞内膜中的 G 蛋白效应器进行信号转导的证据,以及这种信号转导与经典质膜信号转导的不同之处,这对生理学和药理学具有重要意义。我们还强调了 GPCR 信号转导空间偏向的潜在机制,包括细胞内膜及其相关脂质和蛋白质如何影响 GPCR 活性和信号转导。