c-Fos associates with the endoplasmic reticulum and activates phospholipid metabolism.

BUSSOLINO, DF; ME GUIDO,; GA GIL,; GRACIELA ADRIANA BORIOLI; M.L. RENNER,; VR GRABOIS,; CB CONDE,; BL CAPUTTO,

FASEB JOURNAL

Año: 2001 vol. 15 p. 556 - 556

0892-6638

-Fos, a transcription factor that constitutes DNA-binding AP-1 complexes, regulates geneexpression that promotes long-lasting cellular changes. We show that, in addition to itstranscription factor activity, c-Fos regulates the metabolism of phospholipids cytoplasmically byan AP-1-independent activity. Two waves of c-Fos expression that promote subsequent waves ofstimulation of 32P-orthophosphate incorporation into phospholipids are evidenced in quiescentcultured fibroblasts induced to re-enter the cell cycle. The first wave of c-Fos expression peaks at7.5 min and returns to control levels by 15 min. The second wave starts by 30 min and remainselevated at 120 min. In the first wave, the lipids that incorporate 32P are predominantly secondmessengerpolyphosphoinositides (PIP, PIP2, PIP3); whereas in the second wave, membranebiogenesis-related lipids (PI, PE, PA), become radioactive. Both waves of phospholipidactivation depend on