钙对于细胞毒性T淋巴细胞中孔形成蛋白（穿孔素）的膜结合和溶解活性都至关重要。

Calcium is essential for both the membrane binding and lytic activity of pore-forming protein (perforin) from cytotoxic T-lymphocyte.

作者信息

Ishiura S, Matsuda K, Koizumi H, Tsukahara T, Arahata K, Sugita H

机构信息

National Institute of Neuroscience, NCNP, Tokyo, Japan.

出版信息

Mol Immunol. 1990 Aug;27(8):803-7. doi: 10.1016/0161-5890(90)90090-m.

DOI:10.1016/0161-5890(90)90090-m

PMID:2402247

Abstract

The influence of Ca on the membrane binding and lytic activity of lymphocyte pore-forming protein (perforin) was studied. In the absence of Ca, perforin did not bind to the target membranes and did not support lysis of the target cells. In contrast, in the presence of Ca perforin was able to bind to the cell membrane (Km greater than 0.2 mM). Almost all the perforin molecules bind to the membrane within 1 min at 0 degrees C. The addition of EDTA abolished the binding, indicating that the effects of Ca on the membrane binding are reversible. On the other hand, the perforin-mediated lysis of target cells was temp-dependent and also required the presence of Ca in the reaction mixture (Km = 0.05 mM). The difference between the Km values for the membrane binding and lytic activity suggests the presence of two distinct Ca-requiring steps in perforin-mediated target cell lysis.

摘要

研究了钙对淋巴细胞成孔蛋白（穿孔素）膜结合及裂解活性的影响。在无钙条件下，穿孔素不与靶膜结合，也不支持靶细胞的裂解。相反，在有钙的情况下，穿孔素能够结合到细胞膜上（米氏常数大于0.2 mM）。在0℃时，几乎所有的穿孔素分子在1分钟内都能结合到膜上。加入乙二胺四乙酸（EDTA）可消除这种结合，表明钙对膜结合的作用是可逆的。另一方面，穿孔素介导的靶细胞裂解是温度依赖性的，并且反应混合物中也需要有钙的存在（米氏常数=0.05 mM）。膜结合和裂解活性的米氏常数之间的差异表明，在穿孔素介导的靶细胞裂解过程中存在两个不同的需要钙的步骤。