The Osteoclast fusion complex including DC-STAMP (470 aas; 7 TMSs), OC-STAMP (566 aas and 7 TMSs) and Leucocyte surface antigen, CD47 of 323 aas and 5 TMSs (Chiu et al. 2016; Møller et al. 2016; Zhang et al. 2014).  CD47 is homologous to the first 5 TMSs of Presenilin-1 of Homo sapiens (1.A.54.1.1).  It is therefore a presenilin homologue (unpublished observation). Sulforaphene (SFE) downregulates mRNA expression of DC-STAMP, OC-STAMP, and Atp6v0d2, which encode cell-cell fusion molecules (Takagi et al. 2017). SFE attenuates pre-osteoclast multinucleation via suppression of cell-cell fusion. ITIM on DC-STAMP is a functional motif that regulates osteoclast differentiation through the NFATc1/Ca2+ axis (Chiu et al. 2017).