Protein expression of STRA6 during the culture activation of HSCs. Cell lysates were prepared from HSCs at 3 days after plating (HSCs-3d), and from HSCs after passage 1 (P1), 2 (P2), and 3 (P3), and analyzed by Western blotting. Lysates from NIH3T3 cells were used as a negative control. The separating lines demarcate bands that come from non-consecutive lanes of the same gel. 