FGF23 activates FGFR1-Akt-S6K1 and Erk1/2 signalings in osteoblasts. The differentiated OB-6 human osteoblastic cells (A) or the primary murine osteoblasts (D) were treated with FGF23 (25 ng/mL) or PBS (the vehicle control) for 10 min, total cell lysates were collected, with the expression of listed proteins tested by Western blotting (A and D). Stable OB-6 cells, with the applied FGFR1 shRNA (“shFGFR1-Seq1/2”, two non-overlapping sequences), the scramble control shRNA (“shC”), the lentiviral FGFR1-expressing construct (“lv-FGFR1”), or the empty vector (“Vec”), were treated with FGF23 (25 ng/mL) for 10 min, expression of listed proteins in total cell lysates were tested (B and C). For Western blotting assays, the same set of lysate samples were run in sister gels to test different proteins (same for all Figures). The exact same amount of protein lysates, 40 μg lysates per lane, were loaded in each lane (same for all Figures). The listed proteins were quantified and normalized to the loading controls (same for all Figures). Each experiment was repeated three times and similar results were obtained.