GPRASPs regulate HSC migration, survival, and repopulation after transplant by promoting CXCR4 degradation. Under control conditions, both GPRASP1 and GPRASP2 are necessary for the proper degradation of CXCR4. Upon Gprasp1 or Gprasp2 knockdown, CXCR4 degradation is blocked. This provokes an accumulation of this protein, allowing a higher recycling rate to the cell surface and makes the cells more sensitive to the SDF-1–chemoattractive effect, enhancing their migrating, survival, and repopulation potential after transplant.