Is cytoplasmic c-Fos required for neuronal diferentiation?

GABRIEL ORLANDO FERRERO; BEATRIZ LEONOR CAPUTTO

Pinamar, Bs.As.,Argentina

Congreso; Reunión de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2005

Reunión de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB)

c-Fos participates, as a component of AP-1 family of transcription factors, in events related to cell growth and differentiation. A few years ago we found an additional activity for this protein: that is the capacity of c-Fos to activate the phospholipid synthesis machinery. This activation is a cytoplasmic phenomenon involving an association between c-Fos and the endoplasmic reticulum (ER) as was described in the cell lines NIH 3T3, PC12 and T98G cells. Herein, it was examined if this c-Fos activated phospholipid synthesis is also observed in primary cultures of pyramidal hippocampus cells. We found that c-Fos also associates to the ER and activates phospholipids synthesis. This phenomenon is relevant to growth since blocking of c-Fos/ER association with a c-Fos antibody also blocks phospholipid synthesis activation and neuronal differentiation. Subcellular location of c-Fos showed c-Fos/ER co-localization both in the cell soma and in growing axons, the latter mainly ascribed to branching zones. These results support the notion that c-Fos is required to sustain growth by activating the synthesis of phospholipids. Furthermore we are testing c-Fos subcelular localization in growing axons. Herein we postulate c-Fos as necessary step that activates the phospholipids synthesis machinery that sustain neuronal grow.