GPSM1, also named as AGS3, is a receptor-independent G protein activator that has been implicated in multiple biological events such as brain development, neuroplasticity and addiction, cardiac function, Golgi structure/function, macroautophagy and metabolism. It contains seven tetratricopeptide repeats in its N-terminal half and four G-protein regulatory (GPR) motifs in its C-terminal half. It has been shown that AGS3 could regulate the orientation of the mitotic spindle, cAMP production, membrane protein transport, and asymmetric cell division by binding preferentially to inactive Gai/o subunits complexed with guanine dinucleotide phosphate (GDP) at multiple G-protein regulatory or GoLoco motif repeats. It also plays an important anti-apoptotic role through enhancing the phosphorylation of cyclic AMP response element-binding protein (p-CREB).