Ariga T, Yoshino H, Ren S, Pal S, Katoh-Semba R, Yu R K
Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0614.
Biochemistry. 1993 Aug 10;32(31):7904-8. doi: 10.1021/bi00082a010.
We measured the activities of UDP-galactose:globotriaosylceramide alpha 1-3-galactosyltransferase (alpha-GalTase) and protein kinase C (PKC) in PC12D pheochromocytoma (PC12D) cells which were induced to differentiation by nerve growth factor (NGF), forskolin (FRK), staurosporine (STP), retinoic acid (RA), 2-chloroadenosine (ClAd), and/or galactosylceramide (GalCer). NGF, STP, FRK, and RA were found to be stimulators for the PKC activity, whereas ClAd appeared to be an inhibitor of the enzyme. At the concentration of 25 microM, GalCer having normal fatty acids was found to be a stimulator, whereas GalCer having hydroxy fatty acids was ineffective in modulating the PKC activity. Interestingly, all stimulators of PKC activities, including GalCer having normal fatty acids, appeared to be activators for the alpha-GalTase activity. On the other hand, GalCer having alpha-hydroxy fatty acids had no effect and ClAd was found to be a potent inhibitor for the alpha-GalTase activity. These data suggest that alpha-GalTase activity during PC12D cell differentiation may be regulated by a PKC-dependent process.
