TRAF3 and osteoporosis: Particularly, elevated active TGFβ1 with aging induces TRAF3 lysosomal degradation in mesenchymal progenitor cells to inhibit bone formation directly through GSK-3β mediated β-catenin degradation, and to promote OC formation indirectly through NF-κB mediated RANKL production [94], forming the basis of age-related osteoporosis.