Functional involvement of proteins, interacting with sphingolipids, in sphingolipid transport to the canalicular membrane in the human hepatocytic cell line, HepG2?

A photoreactive sphingolipid precursor was used to investigate the potential involvement of protein-lipid interactions that may convey specificity to sphingolipid transport in the human hepatoma cell line, HepG2, A I-125-labeled, photoreactive ceramide, I-125-N-3-Cer, was incubated with the cells and became incorporated into two sphingolipid products, The major product was photoreactive sphingomyelin (I-125-N-3-SM) (25% Of total radioactivity), while only minor amounts of photoreactive glucosylceramide (I-125-N-3-GlcCer) were formed (