Schematic representation of GPRASP control of CXCR4-mediated HSC functions. In homeostasis (Control), GPRASP1 and GPRASP2 regulate CXCR endocytic trafficking and degradation. In the absence of GPRASP1 or GPRASP2, CXCR4 accumulates in HSCs, promoting HSC quiescence, survival, migration, and engraftment capacity. Illustration by Christina M. Termini, UCLA.