Affiliations: Instituto de Biopatologia Química and Unidade de Biopatologia Vascular, Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, 1649-028 Lisboa, Portugal
Note: [] Corresponding author: Carlota Saldanha, Instituto de Biopatologia Química and Unidade de Biopatologia Vascular, Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, 1649-028 Lisboa, Portugal. Tel.: +351 217985136; Fax: +351 217999477; E-mail: carlotasaldanha@fm.ul.pt.
Abstract: The objective of the present work was to study the effects of erythrocyte proteins phosphorylation in erythrocyte aggregation and deformability. Human whole blood samples were incubated in vitro in absent and in presence of the phosphorylation/dephosphorilation band 3 inhibitors and also with adenylyl cyclase, guanylate cyclase and PI3K inhibitors and the erythrocyte aggregation index (AIE) and deformability were assayed. The results show that when band 3 is phosphorylated in presence of a PTP inhibitor an increase in erythrocyte aggregation index is observed (p<0.0001). A partial dephosphorylation band 3 state, induced by PTK inhibitors, show a decrease in the erythrocyte aggregation index (p<0.002). However both manipulated states induced lower EAI values than blood samples aliquots controls. The guanylate cyclase and PI3-K inhibitors significantly decrease the erythrocyte aggregation index in relation with the control blood samples. Erythrocyte deformability in presence of all the inhibitors did not showed significant changes. PTP and PI3-K inhibitors showed a significantly increase in the plasma potassium concentrations not associated with EAI values. Methehemoglobin levels were increased significantly when guanylate cyclase inhibitor is present in the blood samples. In conclusion, the results suggest that erythrocyte aggregation index is dependent of the phosphorylated/dephosphorylated state of band 3.
Keywords: Band 3, erythrocyte, phosphorylation, dephosphorylation, protein tyrosine kinase, protein tyrosine phosphatase
