Promotes osteoblast cell differentiation and terminal mineralization. Plays a role in inducing the cell cycle arrest via inhibiting CCND1 expression in all-trans-retinoic acid (ATRA) signal pathway (By similarity). Interacts with NELL1; the interaction promotes osteoblastic differentiation and mineralization. Colocalizes with NELL1 on the nuclear envelope and the perinuclear region. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Wrong choice of CDS.