Component of the ceramide synthase complex required for C26-CoA-dependent ceramide synthesis. Facilitates ER-to-Golgi transport of GPI-anchored proteins (By similarity). Has a role in meiosis. a fatty acyl-CoA + sphing-4-enine = an N-acylsphing-4-enine + CoA + H(+) Belongs to the sphingosine N-acyltransferase family.