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.
Borioli
Graciela A
GA
Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Pabellón Argentina, Ciudad Universitaria, Córdoba, Argentina. gborioli@dpb.fcq.unc.edu.ar
Fanani
María L
ML
Caputto
Beatriz L
BL
Maggio
Bruno
B
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