RUNX2 and osteoporosis: Osteoporosis causes a major economic burden worldwide.[17] Enhancing OB differentiation to antagonize excessive bone loss or defects in bone formation has been proposed as a novel strategy.[18] Although multiple factors promote OB differentiation, especially transcription factors in the nucleus, few of them have been targeted for therapy.[7, 19] In this research, NIBAN2 was identified as a novel factor promoting OB differentiation through regulation of RUNX2 alternative splicing.