Na_2SeO_3对血影收缩蛋白(spectrin)与肌动蛋白(actin)相互作用的影响

Na_2SeO_3不影响肌动蛋白(actin)的聚合,但它可通过与血影收缩蛋白(spectrin)作用而间接促进actin的聚合。Na_2SeO_3的作用具有浓度依赖性:低浓度(0.5-5.0ppm)可提高actin聚合过程的成核速度及延伸速度,高浓度则产生相反的效应。巯基试剂如N-乙基马来酰亚胺(NEM)可消除硒的效应。因此,推测适量的硒可能导致spectrin构象发生一定变化,增强spectrin与actin的结合,降低actin链解聚的倾向性,从而稳定红细胞膜骨架。

EFFECT OF Na_2SeO_3 ON THE INTERATION OF SPECTRIN WITH ACTIN

No obvious effect was observed on the polymerization of actin by Na2SeO3. However, in the presence of human erythrocyte spectrin, Na2SeO3 could markedly enhance the polymerization rate of actin.Such Se effect was concentration -dependent. In the presence of trace amount of Na2SeO3 (0.1-10.0 ppm) both nucleation and elongation rates of actin polymerization were detected, but an increase result appeared only with a Na2SeO3 concentration of 0.5-5.0 ppm. An opposite effect of Na2SeO3 was observed at a higher concentration. We also found that sulfhydryl reagen NEM could eliminate the Se effect. It may deduced that in the presence of an appropriate amount of Na2SeO3 the association of spectrin with actin oligomers, and hence the stabilization of erythrocyte membrane skeleton might be strengthened in consequence of the confor-mational changes of spectrins induced by the interaction of their SH groups with Na2SeO3.