|Budget Amount *help
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1999 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1998 : ¥2,600,000 (Direct Cost : ¥2,600,000)
Sendai virus induces the fusion of human erythrocytes in the presence of exogenous CaィイD12+ィエD1. Fused erythrocytes of large sizes having a diameter of more than 10 times as compared to that of a single erythrocytes were detected. Under these conditions, calcium-activated neutral protease (μ-calpain) in erythrocytes was activated autolytically in accordance with fusion.
To identify the protein species which are degraded upon activation of intracellular μ-calpain, the proteins recovered in the membrane fractions were analyzed by SDS-PAGE and immunoblotting. Limited and specific degradation of ankyrin, one of the membrane skeleton proteins, was observed.
A specific calpain inhibitor, Cbz-Leu-Leu-aldehyde (ZLLal), inhibited membrane fusion, autolytic activation of μ-calpain and the degradation of ankyrin. A specific inhibitor of the proteasome, Lactacystin, did not inhibit the activation of μ-calpain and the degradation of ankyrin by treatment with CaィイD12+ィエD1 and A23187. These results suggested that Sendai virus induced fusion of erythrocytes is regulated by the activation of μ-calpain, followed by the degradation of ankyrin.