c-Fos activates glycolipid synthesis by activating the first glycosyltransferase of their synthesis

CRESPO, PILAR MARIA; SILVESTRE, DAVID; MACCIONI, HUGO J.F.; DANIOTTI, JOSE LUIS; CAPUTTO, BEATRIZ

JOURNAL OF BIOLOGICAL CHEMISTRY

American Society for Biochemistry and Molecular Biology

Lugar: Bethesda, USA; Año: 2008 vol. 283 p. 31163 - 31163

0021-9258

It has been demonstrated that c-Fos has, in addition to its wellrecognized AP-1 transcription factor activity, the capacity toassociate to the endoplasmic reticulum and activate keyenzymes involved in the synthesis of phospholipids required formembrane biogenesis during cell growth and neurite formation.Because membrane genesis requires the coordinated supply ofall its integral membrane components, the question emerges asto whether c-Fos also activates the synthesis of glycolipids,another ubiquitous membrane component. We show that c-Fosactivates the metabolic labeling of glycolipids in differentiatingPC12 cells. Specifically, c-Fos activates the enzyme glucosylceramidesynthase (GlcCerS), the product of which, GlcCer, is thefirst glycosylated intermediate in the pathway of synthesis ofglycolipids. By contrast, the activities of GlcCer galactosyltransferase1 and lactosylceramide sialyltransferase 1 are