FIGURE 7.

Biochemical analysis of the intracellular location of Sil3-derived GFP fusion proteins T1 and T6. Subcellular membrane fractions F1–F7 of T. pseudonana transformants were isolated by density sucrose gradient centrifugation according to an established protocol (25): F3/F4 = ER membranes, F5 = Golgi membranes, and F6/F7 = mitochondria and plasma membrane. Equal aliquots of the fractions were separated by SDS-PAGE and probed for the presence of T1-GFP (A) and T6-GFP (B) by Western blot analysis using anti-GFP antibodies. As a reference, the same membrane fractions from the T. pseudonana transformants were analyzed for the presence of the ER-resident kinase tpSTK1 using previously generated anti-tpSTK1 antibodies (25).