FIG. 1.
Functional and regulatory properties of recombinant human Pit-2 proteins Pit-2ɛɛ (A) and Pit-2–GFP (B). Short-term (2-min) Pi transport was determined in control pɛMTH and pPit2ɛ-ɛMTH-transfected NIH 3T3 fibroblasts as indicated in Materials and Methods. Cells were grown in serum-free medium with 20 μM zinc acetate to up-regulate the metallothionein promoter and then treated with 1 μM PMA for 10 min as indicated (C). (D) Pi uptake of pɛMTH vector- and pPit2ɛ-ɛMTH vector-transfected fibroblasts, as well as in these transfected cells productively infected with A-MuLV. Each column represents the mean ± standard error of the mean of three independent experiments performed in duplicate.