CerS3 activity is activated by ACBP and depends on ligand binding to ACBP. Homogenates were prepared from HEK293T cells overexpressing CerS3 and CerS3 activity was determined using C26:0-CoA after addition of purified recombinant ACBP or a mutated form of ACBP (A), which binds ligand with very low affinity, or purified recombinant liver FABP1 (B). The values are shown as means ± S.D., n = 3. Statistical analyses were performed using unpaired t test. *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001.