Exhaustive running exercise induce tyrosine phosphorylation of band 3 in rat erythrocytes.

BACKGROUND/AIMS In vitro studies have shown that band-3 function is mainly regulated by its phosphorylation status. The main purpose of the study was to investigate whether band-3 phosphorylation status interferes with an exhaustive running exercise-related dysfunction of RBC deformability. METHODS Rats were divided into sedentary control (C) and exercise test (ET) groups. The ET group was divided further into exhaustive running exercise (ERE) and moderate running exercise (MRE) subgroups. RESULTS Tyrosine phosphorylation of band-3 was significantly elevated in the absence of reducing agent, consistent with the emergence of band-3 clustering in the ERE group compared with the control and MRE groups. The elongation index (EI) was found to decline significantly in the ERE group compared with the C and MRE groups under shear stress (control group, 0.41 ± 0.01 at 3 Pa and 0.571 ± 0.008 at 30 Pa; ERE group, 0.3140 ± 0.013 at 3 Pa and 0.534 ± 0.009 at 30 Pa; P < 0.001 and P < 0.002, respectively). CONCLUSION Our results suggest that exhaustive running exercise results in elevated band-3 tyrosine phosphorylation and alters band-3 membrane organization. Furthermore, it appears that exhaustive running exercise induced band 3 phosphorylation is due to the oxidation of critical sulfydryl groups of a membrane phosphatase (PTP).