MVP and osteoporosis: Our results indicate that MVP in osteoclasts may be critically involved in inhibiting bone mass which is supported by three primary results from our in vivo and in vitro studies: 1) Mvp-/-mice and Mvpf/fLyz2-Cre mice both exhibit osteoporosis phenotypes which correlate with increased osteoclasts infiltration in osteolytic lesions in the distal femur (Figure 2 and 3).