Pesticide effects on protein phosphorylation patterns in fish

FERRARI ANA; VENTURINO ANDRÉS; PECHÉN DE D'ANGELO ANA M

Villa Carlos Paz, Córdoba, Argentina

Congreso; XXXVIII Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular (SAIB); 2002

SAIB

Subacute and long-term effects of pesticide exposures involve molecular effectors in the signaling transduction and genetic response to 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 SDS-PAGE and autoradiography. A visible reduction of phosphorylation in an hepatic 65-Kda protein band in the nuclear fraction was observed with both insecticides, as well as an increase in 171-kDa protein band, with or 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 65-Kda band decreases while an additional phosphorylated protein (162-kDa) appears. On the other hand azinphosmethyl produce 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.