| Modification Notes |
Bone homeostasis is accomplished by the balance of osteoblast and osteoclast activity. DC-STAMP (DC-specific transmembrane protein), also known as Transmembrane 7 superfamily member 4, is a 470 amino acid multi-pass membrane protein that regulates osteoclast and macrophage cell fusion. With localization at the cell surface, DC-STAMP is highly expressed in dendritic cells of the lung, kidney, liver and lymph nodes and is expressed at lower levels in spleen, bone marrow, leukocytes and pancreas. Mice that lack the gene encoding DC-STAMP exhibit upregulation of bone formation by osteoblasts and decreased bone reabsorption, ulitmately leading to an increase in bone mass. Alternatively, mice that overexpress the DC-STAMP gene show decreased osteoblast activity and bone mass, due to accelerated cell-cell fusion of osteoclasts. This evidence suggests that DC-STAMP plays an essential role in osteoclastogenesis. |