c-Fos is a surface pressure-dependent diverter of phospholipase activity.
c-Fos, a transcription factor, associates to endoplasmic reticulum and modulates phospholipid biosynthesis. Its surface thermodynamic properties allow it to differentially interact with phospholipid monolayers with a selective dependence on the lipid polar head group and the lateral surface pressure. We explored the c-Fos ability to modulate phospholipid degradation by phospholipases (ppPLA2, Bacillus cereus PLC, and sphingomyelinase) using the monolayer technique. Experiments conducted under constant packing conditions show that c-Fos modulates phospholipase activity in a finely tuned way, depending on the membrane intermolecular packing. Surface lateral pressures above 12-16 mN/m induce c-Fos to activate phospholipase A2 and sphingomyelinase, and abolish phospholipase C activity. The effects of c-Fos on other steps of the catalytic process, lag-time and extent, are synergic with those on activity. We show for the first time that c-Fos participates in modulating phospholipid degradation and that it can affect the formation of lipid second messenger products by PLA2, PLC, and sphingomyelinase.
Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Pabellón Argentina, Ciudad Universitaria, Córdoba, Argentina. gborioli@dpb.fcq.unc.edu.ar
Graciela A
GA
Borioli
María L
ML
Fanani
Beatriz L
BL
Caputto
Bruno
B
Maggio
D000818:Animals; D001409:Bacillus cereus / Q000201:enzymology; D002384:Catalysis; D004247:DNA / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D050356:Lipid Metabolism; D010741:Phospholipases A / Q000037:antagonists & inhibitors*; D054467:Phospholipases A2; D010743:Phospholipids / Q000378:metabolism; D011312:Pressure; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors*; D013552:Swine; D013997:Time Factors; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors* / Q000378:metabolism
D010743:Phospholipids; D016760:Proto-Oncogene Proteins c-fos; D011994:Recombinant Proteins; D004247:DNA; D010741:Phospholipases A; D054467:Phospholipases A2; D010738:Type C Phospholipases; D013108:Sphingomyelin Phosphodiesterase