ScienceAsia 28 (2002): 313-317 |doi: 10.2306/scienceasia1513-1874.2002.28.317
Status of Red Cell Membrane
Protein Phosphorylation in Thalassemia
Rutaiwan Tohtong*, Pornpimol Metheenukul and Prapon Wilairat
ABSTRACT: The steady-state levels of beta-spectrin phosphorylation in HbH (alpha-thalassemia 1/alpha-thalassemia 2), HbH/HbConstant Spring (alpha-thalassemia 1/HbCS, hereafter called HbH/HbCS) and nonsplenectomized beta-thalassemia/HbE (hereafter called beta-thal/HbE) red cells were quantitated using Western hybridization. Phosphorylation of beta-spectrin serine and threonine residues from thalassemic samples was not significantly different from normal control. However, tyrosine phosphorylation was higher than normal control in HbH (p<0.01), HbH/HbCS (p<0.05) and beta-thal/HbE (p<0.05) samples. Tyrosine phosphorylation of beta-spectrin was observed only in the presence of vanadate, a phenomenon not hitherto reported. As tyrosine kinase activity has been linked to oxidative stress, loss of membrane lipid asymmetry and procoagulant activity of the red cell membrane, the observed increase in beta-spectrin tyrosine phosphorylation of the thalassemic red cells is likely, at least in part, to account for these parameters.
Department of Biochemistry, Faculty of Science, Mahidol University, Rama 6 Road,
Bangkok 10400, Thailand.
* Corresponding author, E-mail: email@example.com
Received 31 Oct 2001, Accepted 22 Apr 2002