Yamaguchi M
Laboratory of Metabolism and Endocrinology, Graduate School of Nutritional Sciences, University of Shizuoka, Japan.
Mol Cell Biochem. 1992 Jul 6;113(1):63-70. doi: 10.1007/BF00230886.
The effect of regucalcin, a calcium-binding protein isolated from rat liver cytosol, on Ca2+ transport in rat liver nuclei was investigated. Ca2+ uptake and release were determined with a Ca2+ electrode. Ca2+ uptake increased dependent on adenosine triphosphate (ATP; 0.5-2.0 mM), while the uptake was negligible in the presence of 2 mM ADP or AMP. Regucalcin (0.5-2.0 microM) had no effect on Ca2+ uptake following addition of 2.0 mM ATP. Meanwhile, Ca2+, which accumulated in the nuclei during 10 min after ATP addition, was significantly released by the addition of regucalcin. This release was dose-dependent (0.1-2.0 microM). Vanadate (100 microM) and guanosine triphosphate (100 microM) did not cause a significant release of Ca2+ from the nuclei. Trifluoroperazine (TFP; 50 microM), an antagonist of calmodulin, significantly increased Ca2+ release from the nuclei. The presence of regucalcin (0.5 microM) further enhanced the TFP effect. These results indicate that regucalcin stimulates Ca2+ release from liver nuclei, and that the effect is not influenced by calmodulin antagonist. The finding suggests that regucalcin can regulate the Ca2+ transport system in rat liver nuclei.
研究了从大鼠肝脏细胞质中分离出的钙结合蛋白调钙素对大鼠肝细胞核中Ca2+转运的影响。用Ca2+电极测定Ca2+的摄取和释放。Ca2+摄取量随三磷酸腺苷（ATP；0.5 - 2.0 mM）浓度增加而增加，而在存在2 mM二磷酸腺苷（ADP）或一磷酸腺苷（AMP）时摄取量可忽略不计。加入2.0 mM ATP后，调钙素（0.5 - 2.0 microM）对Ca2+摄取无影响。同时，在加入ATP后10分钟内积累在细胞核中的Ca2+，在加入调钙素后显著释放。这种释放呈剂量依赖性（0.1 - 2.0 microM）。钒酸盐（100 microM）和三磷酸鸟苷（100 microM）不会导致细胞核中Ca2+的显著释放。钙调蛋白拮抗剂三氟拉嗪（TFP；50 microM）显著增加细胞核中Ca2+的释放。调钙素（0.5 microM）的存在进一步增强了TFP的作用。这些结果表明，调钙素刺激肝细胞核中Ca2+的释放，且该作用不受钙调蛋白拮抗剂的影响。这一发现表明，调钙素可调节大鼠肝细胞核中的Ca2+转运系统。
