Role of furin in the production of mature integrin and growth factors.
(A) Megakaryoblastic Dami cells were cultured with 100 nM PMA for various time periods, as indicated, supernatants were collected, and TGF-β1 and PDGF AB were measured by ELISA. Corresponding cell lysates were separated by SDS-PAGE and immunoblotted using αIIb-specific antibodies (1:1000). Western blots were scanned, and differences in staining intensity were measured using NIH image software. Western blot results are expressed as a ratio of mature to precursor forms, which is an estimation of conversion efficiency. (B) Dami cells were incubated overnight in the presence of 100 nM PMA. Cells were infected with the indicated recombinant adenovirus. Forty-eight–hour supernatants were collected for TGF-β1 and PDGFAB determination. Data are expressed as the mean ± SEM; n = 3. **P < .001, compared with control adenovirus. (C) Cells were coinfected with the indicated recombinant adenovirus. 48 hours after infection, supernatants were concentrated, separated on SDS-PAGE gels, and immunoblotted using an anti–TGF-β–specific antibody (1:1000; R&D Systems).
