The interleukin (IL)-4, 1,25(OH)₂D₃ and retinoic acid, increase surface expression of functional integrin α_vβ₃ 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 α_v remain unchanged. In each instance, the increase in the surface expression of the integrin results in increased migration of the cells onto an α_vβ₃ substrate. Because β₃ subunit, except platelet where β₃ subunit conform a dimer with α_IIb, associates solely with α_v subunit monogamously, while promiscuous α_v subunit combines with various subunit, our present data support the idea that the β₃ subunit governs the surface-expressed functional integrin complex.