Band 3 modifications and Syk activation following diamide treatment. RBCs were treated with increasing concentration of diamide for 30 min in the presence or in the absence of 10 µM Syk inhibitor II (Syk I.). Band 3 tyrosine phosphorylation (panel (a)). Band 3 oxidative crosslinking (oxidized band 3, Dia) expressed as the amount of oligomeric band 3 (apparent M.W. higher than 200 KDa) under nonreducing conditions (panel (b)). Syk tyrosine phosphorylation measured in whole cellular extracts (panel (c)). Syk bound to the membranes (Syk translocation) (panel (d)). Western blotting was quantified using an IR fluorescence detection scanner (Odyssey, Licor, USA). Images were analyzed by Odyssey V3.0 software. Values are representative of 4 separated experiments and are expressed as arbitrary units (au); the bars represent the standard deviations.