Toxoplasma gondii attachment to host cells is regulated by a calmodulin-like domain protein kinase
Toxoplasma gondii attachment to host cells is regulated by a calmodulin-like domain protein kinase
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DOI：
10.1074/jbc.m011045200
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发表时间：
2001-04-13
影响因子：
4.8
通讯作者：
Beckers, C
中科院分区：
文献类型：
--
作者：
Kieschnick, H;Wakefield, T;Beckers, C
本文分析了钙依赖性蛋白激酶在弓形虫侵入宿主细胞中的作用。KT 5926是其他系统中钙依赖性蛋白激酶的抑制剂，已知可阻断。弓形虫速殖子的运动性及其对宿主细胞的附着。在体内，KT 5926仅阻断三种寄生虫蛋白的磷酸化，并且在寄生虫提取物中仅检测到单一KT 5926敏感性蛋白激酶活性。这种活性是钙依赖性的，但不需要钙调蛋白，在弓形虫中的钙依赖性蛋白激酶的搜索中，检测到钙调蛋白样结构域蛋白激酶（CDPKs）的类的两个成员。TgCDPK 2在弓形虫速殖子中仅表达于mRNA水平，未检测到蛋白质; TgCDPK 1在弓形虫速殖子中有表达，并与KT 5926敏感蛋白激酶活性的峰值相一致。TgCDPK 1激酶活性是钙依赖性的，但不需要钙调蛋白或磷脂。研究发现，在阻断寄生虫附着于宿主细胞的浓度下，KT 5926可有效抑制TgCDPK 1。在体外，TgCDPK 1磷酸化三种寄生虫蛋白，迁移相同的三个KT 5926敏感的磷蛋白在体内检测，基于这些观察结果，TgCDPK 1在调节弓形虫运动和宿主细胞入侵的核心作用。
The role of calcium-dependent protein kinases in the invasion of Toxoplasma gondii into its animal host cells was analyzed. KT5926, an inhibitor of calcium-dependent protein kinases in other systems, is known to block. the motility of Toxoplasma tachyzoites and their attachment to host cells. lit vivo, KT5926 blocks the phosphorylation of only three parasite proteins, and in parasite extracts only a single KT5926-sensitive protein kinase activity was detected. This activity was calcium-dependent but did not require calmodulin, In a search for calcium-dependent protein kinases in Toxoplasma, two members of the class of calmodulin-like domain protein kinases (CDPKs) were detected. TgCDPK2 was only expressed at the mRNA level in tachyzoites, but no protein was detected, TgCDPK1 protein was expressed in Toxoplasma tachyzoites and cofractionated precisely with the peak of KT5926-sensitive protein kinase activity. TgCDPK1 kinase activity was calcium-dependent but did not require calmodulin or phospholipids. TgCDPK1 was found to be inhibited effectively by KT5926 at concentrations that block parasite attachment to host cells. In vitro, TgCDPK1 phosphorylated three parasite proteins that migrated identical to the three KT5926-sensitive phosphoproteins detected in vivo, Based on these observations, a central role is suggested for TgCDPK1 in regulating Toxoplasma motility and host cell invasion.