Pesticide effects on protein phosphorylation patterns in fish

FERRARI A; VENTURINO A; PECHEN DE D'ANGELO A.M

Villa Carlos Paz

Congreso; XXXVIII Reunión Anual de la SAIB; 2002

SAIB

Subacute and long-term effects of pesticide exposures involve molecular effectors in the signaling transduction and genetic re­sponse lo the stress. Protein kinase/phosphatase cascades play es­sential roles in the toxicity of pesticides and organic pollutants. We present data on hepatic and cerebral protein in vitro phosphoryla­tion of juvenile rainbow trout (Oncorhynchus mykiss) exposed to 0.005 mg/L of azinphosmethyl or 3 mg/L of carbaryl. Nuclear and mitochondrial synaptosomal fractions were analyzed by incubat­ing them with 32P(gama)ATP and with ortovanadate (ATPase in­hibitor) or genistein (tyrosine-kinase inhibitor), followed by SDS­PAGE and autoradiography. A visible reduction of phosphorylation in an hepatic 64-Kda protein band in the nuclear fraction was ob­served with both insecticides, as well as an increase in 171-kDa protein band, wilh 01' without inhibitors. Fishes exposed to azinphosmethyl present also an increase in phosphorylation of a 22-kDa protein, which is more noticeable with ortovanadate. Car­baryl exposure produces an attenuation of 22-kDa band phospho­rylation in brain synaptosomal fraction while it augments in nuclear fraction, suggesting a probable protein relocalization. Coincidently with the effect observed in liver, phosphorylation in 64-Kda band decreases while an additional phosphorylaled protein (162-kDa) appears. On the other hand azinphosmethyl produces also an in­crease in the phosphorylation of 22-kDa protein in brain when ortovanadate was present. These preliminary results showing al­terations in the kinase- phosphatase pathways due to pesticide ex­posure imply changes in signal transduction or' cellular dysfunc­tions, which might be related to toxicological actions and/or responses to xenobiotic stress.