Figure 5.

hACBD6 regulates the acylation rate of LPC by CT775. Measurements of CT775 activity were performed with [¹⁴C]-C_18:1-CoA in the presence of 20 μmol/L LPC at 37°C. As indicated in each panel, [¹⁴C]-C_18:1-CoA was preincubated with purified hACBD3 or hACBD6 before initiation of the acylation reaction by addition of CT775. The standard deviations of at least three different measurements are indicated as error bars. (A) The activity rate values (pmoles of PC formed/μg of protein per min) were calculated from 0 to 6 min with 40 μg proteins of a cleared lysate obtained from the BL21DE3 strain producing CT775. Values are reported relative to the activity rate value obtained at the concentration of 1 μmol/L acyl-CoA w/o hACBD6. Filled bars show rate values obtained in presence of 1 μmol/L purified hACBD6. (B) The activity rate values (pmoles of PC formed/μg of protein per min) were calculated from 0 to 6 min with 4 μg proteins of a membrane preparation obtained from the BL21DE3 strain producing CT775. Measurements were performed with 1 μmol/L [¹⁴C]-C_18:1-CoA preincubated with the indicated concentration of purified hACBD3 and hACBD6. (C) Amounts of PC formed after 2 h incubation of CT775 with 1 μmol/L acyl-CoA and with the indicated concentrations of hACBD6 are reported relative to the value obtained in reaction performed in absence of hACBD6. Note that the total amount of PC formed after 2 h of incubation was not dependent of the initial acylation rate. PC, phosphatidylcholine.