Regulatory factor which is ligand for CMKLR2 and is involved in the modulation of neural stem-cell proliferation and differentiation. Expressed in the hippocampus and detected also in the cortex (at protein level). Detected as early as 12.5 dpc, expression peaks between postnatal day 1 and day 7 and decreases at week 8 after birth (at protein level). Expression decreases upon brain injury. Belongs to the TAFA family.