Modulation of α v β 3 Integrin via Transactivation of β 3 Integrin Gene on Murine Bone Marrow Macrophages by 1,25(OH) 2 D 3 , Retinoic Acid and Interleukin-4

The interleukin (IL)-4, 1,25(OH)2D3 and retinoic acid, increase surface expression of functional integrin αvβ3 on murine osteoclast precursors. All three agonists stimulate transcription of the β3 gene, leading to increased steady-state levels of mRNA this protein. By contrast, mRNA levels of αv remain unchanged. In each instance, the increase in the surface expression of the integrin results in increased migration of the cells onto an αvβ3 substrate. Because β3 subunit, except platelet where β3 subunit conform a dimer with αIIb, associates solely with αv subunit monogamously, while promiscuous αv subunit combines with various subunit, our present data support the idea that the β3 subunit governs the surface-expressed functional integrin complex.