Effect of light on signaling pathways in a photoreceptor cells nuclear fraction from bovine retina

NATALINI, P.; MATEOS, M. V.; GIUSTO, N. M.; ILINCHETA, M.

Buenos Aires

Congreso; SAIB-Molecular mechanisms in cell signaling and gene expression; 2013

The aim of this work was to evaluate the effect of light exposure on signaling pathways in a fraction enriched in photoreceptor cell nuclei (PNF) from bovine retina. We studied whether the exposure of bovine retina to light causes any changes in the PNF fraction in the activation and localization of MAPKs and proteins involved in two canonical signaling pathways, PIP2-PLC-PKCs and PI3K-Akt. Bovine eyes were adapted to darkness (2 h, 0° C), and then eye cups were exposed to light (280 cd, 30 min) or to dark. PNF was obtained by ultracentrifugation onto a discontinuous sucrose gradient. Light-induced DNA damage was evaluated by immunofluorescence. PKCalpha, Akt and ERK1/2 total and activated content was detected by Western Blot. No DNA fragmentation was observed in dark or light condition. Light causes an increase in the content of activated PKCalpha with respect to the dark condition in the PNF (2.5 fold and 3- fold respectively), with similar levels of total forms. Likewise, an increase in the content of activated Akt (3-fold) without changes in total Akt was seen. A significant increase was also observed in response to light in the content of total and phosphorylated form of ERK1/2 (2-fold) in PNF. Our results demonstrate that, in absence of nuclear damage, ERK and signaling pathways linked to GPCR and RTK were activated in PNF when bovine retina was exposed to light.