c-Fos interacts differentially with acidic phospholipids and regulates phospholipase activity at membrane level

GRACIELA ADRIANA BORIOLI

Buenos Aires

Congreso; XIV International Biophysics Congress, IUPAB/SAB; 2002

.IUPAB/SAB

The oncoprotein c-Fos activates phospholipid biosynthesis both in vivo and in vitro through a novel activity that is cytoplasmic, associated with endoplasmic reticulum, and independent of its well established transcriptional function. Using monolayer techniques we showed that c-Fos has surface activity and interacts differentially with phospholipids like phosphatidylglicerol, phosphaditylserine and especially phosphatidyl inositoldiphosphate. It can thus participate in some processes that occurr in the membrane. A possible function of c-Fos in vivo through interaction whith membrane phospholipids is further supported by the protein's ability to modulate PLA2, sphingomyelinase and PLC activity in lipid monolayers at surface lateral pressures between 12 and 20 mN/m. We have initiated studies to elucidate the mechanism by which c-Fos could play a role in phospholipid metabolism. Preliminary results suggest that c-Fos affects phospholipid intermolecular packing as a consequence of its own reorganization in the range of surface lateral pressure at which it modulates phospholipase activity . Such changes may modify, among others, cellular functions related to phospholipid metabolism.