Figure 7.

Activity of differentially tagged forms in single and dual expression system. Isoform 2 and 3 were cloned in a dual expression vector, which allows production of 1 or 2 proteins tagged with unique epitope either at their N-terminus (N_ter-isoform) or C-terminus (C_ter-isoform). Shown are the activity measurements performed with membrane fractions isolated from cells expressing either a single copy of isoform 2 produced with a tag at the N-terminus (N_ter-2 sample) or at the C-terminus (C_ter-2 sample), one copy of isoform 3 (N_ter-3), two copies of isoform 2 (N_ter-2/C_ter-2 sample), two copies of isoform 3 (N_ter-3/C_ter-3 sample), or one copy of isoform 2 and one copy of isoform 3 (N_ter-2/C_ter-3 sample). Measurements were performed with 5 μM (¹⁴C)-C_18:1-OH. A. Activity rates were normalized to the amount of N-terminally fused proteins present in the different membrane fraction. For the C_ter-2 sample, this value was calculated relative to the amount of the ACSL6 enzyme present. The normalized values obtained with the sample producing a single protein in its most active version, N_ter-2 (1^st bar), was arbitrary set at a value of 1 and was used to report the relative values obtained with the other samples. B. Shown are the activity rate values relative to the amount of the total proteins present in the different membrane fractions and they represent the raw activity data of the normalized values shown in panel A. Averages and the standard deviations of 3 different experiments are shown.