
内在化の過程でヘテロ三量体G蛋白質は細胞膜と比べて低密度になる。受容体活性化によってもこの傾向は変わらない。


coremsg

Classical G protein-coupled receptor (GPCR) signaling takes place in response to extracellular stimuli and involves receptors and heterotrimeric G proteins located at the plasma membrane. It has recently been established that GPCR signaling can also take place from intracellular membrane compartments, including endosomes that contain internalized receptors and ligands. While the mechanisms of GPCR endocytosis are well understood, it is not clear how well internalized receptors are supplied with G proteins. To address this gap we use gene editing, confocal microscopy, and bioluminescence resonance energy transfer to study the distribution and trafficking of endogenous G proteins. We show here that constitutive endocytosis is sufficient to supply newly internalized endocytic vesicles with 20-30% of the G protein density found at the plasma membrane. We find that G proteins are present on early, late, and recycling endosomes, are abundant on lysosomes, but are virtually undetectable on the endoplasmic reticulum, mitochondria, and the medial Golgi apparatus. Receptor activation does not change heterotrimer abundance on endosomes. Our findings provide a subcellular map of endogenous G protein distribution, suggest that G proteins may be partially excluded from nascent endocytic vesicles, and are likely to have implications for GPCR signaling from endosomes and other intracellular compartments.

### Competing Interest Statement

The authors have declared no competing interest.

Visualization of endogenous G proteins on endosomes and other organelles

内在化の非効率性により-ヘテロ三量体g蛋白質の細胞内小器官での存在量が制限される


内在化の非効率性により、ヘテロ三量体G蛋白質の細胞内小器官での存在量が制限される
