P2RY8 is a G protein–coupled receptor (GPCR) that is involved in restraining germinal center (GC) B cell migration and growth. It is unclear how the ligand of P2RY8, S -geranylgeranyl-l-glutathione (GGG), is involved in these processes. Using gain-of-function mouse models and genetically modified human T cells, Gallman et al. showed that expression of gamma-glutamyltransferase-5 (Ggt5) on stromal cells and ATP-binding cassette subfamily C member 1 (Abcc1) on hematopoietic cells was involved in catabolizing and transporting GGG, respectively, and restraining P2RY8+ cells within GCs. GGG and P2RY8 interactions also restrained lymphocyte trafficking to the bone marrow. Thus, GGG and P2RY8 processing and interactions are crucial for the confinement of B cells within GCs and for inhibiting migration of lymphocytes into bone marrow.
P2RY8 promotes the confinement and growth regulation of germinal center (GC) B cells, and loss of human P2RY8 is associated with B cell lymphomagenesis. The m