Figure 4.

FK506 specifically interferes with the interaction between FKBP12 and the activin type I receptor R1 as detected in the small molecule reverse two-hybrid system. Sc* refers to synthetic complete (Sc) medium without any sugar; gal/raf, 2% galactose plus 1% raffinose; and glc, 2% glucose. (A) Phenotypes of R1C–FKBP12 interaction and its dissociation by FK506. Yeast transformants with both vectors appear within 24–36 h on Sc-H-W plates. Colonies were picked and patched on various selective plates for reported gene assays. Each pairwise transformation was analyzed by six independent transformants, three of which are shown here. (B) FK506-mediated 5-FOA resistance is specific to R1C–FKBP12 transformants. (C) Detection of the FK506 effect in liquid media using arrayed nanodroplets (≈200-nl vol) (36). The droplets containing yeast, medium, and FK506 beads were formed in polydimethylsiloxane plastic molded to contain wells 40 μm in depth, 1 mm in diameter, and 250 μm apart from each other.