Acts as a chemokine-like protein by regulating cell proliferation and migration through activation of G protein-coupled receptors (GPCRs), such as S1PR2 and FPR2 (PubMed:29453251, PubMed:29138422). Stimulates chemotactic migration of macrophages mediated by the MAPK3/ERK1 and AKT1 pathway (PubMed:29138422). Blocks TNFSF11/RANKL-induced osteoclast formation from macrophages by inhibiting up-regulation of osteoclast fusogenic and differentiation genes (PubMed:29138422). Stimulation of macrophage migration and inhibition of osteoclast formation is mediated through the GPCR FPR2 (PubMed:29138422). Acts as an adipokine by negatively regulating vascular smooth muscle cell (VSMC) proliferation and migration in response to platelet-derived growth factor stimulation via GPCR S1PR2 and G protein GNA12/GNA13-transmitted RHOA signaling (By similarity). Inhibits injury-induced cell proliferation and neointima formation in the femoral arteries (PubMed:29453251). Expressed in the subcutaneous, brown, epididymal and perirenal adipose tissue (at protein level). Repressed in epididymal adipose tissue of diet-induced obese mice or leptin receptor-deficient mice. Contains a predicted signal peptide at positions 1-25. Belongs to the TAFA family.