Two conserved amino acid motifs mediate protein targeting to the micronemes of the apicomplexan parasite Toxoplasma gondii
Two conserved amino acid motifs mediate protein targeting to the micronemes of the apicomplexan parasite Toxoplasma gondii
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DOI：
10.1128/mcb.20.19.7332-7341.2000
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发表时间：
2000-10-01
影响因子：
5.3
通讯作者：
Crisanti, A
中科院分区：
文献类型：
--
作者：
Di Cristina, M;Spaccapelo, R;Crisanti, A
刚地弓形虫微线蛋白2（MIC2）与不同顶复门寄生虫的一系列粘附分子具有序列和结构相似性。这些分子积累，通过一个未知的机制，在分泌囊泡（微丝），与管状和膜结构一起形成顶复门寄生虫的运动和入侵机制。我们的研究结果表明，两个保守的基序放置在细胞质结构域的MIC 2都是必要的和足够的靶向蛋白T。弓形虫微丝。第一个基序基于氨基酸序列SYHYY。数据库分析显示，一个类似的序列是目前为止在不同的apicomplexan物种的所有跨膜微线蛋白质的胞质尾。第二个信号由一段酸性残基EIEYE组成。在保留的间隔构型中仅含有两个基序SYHYY和EIEYE的人工尾的产生足以将表面蛋白SAG1靶向T的微线体。刚地。这些发现揭示了控制微线内容物形成的分子机制以及将这些细胞器与寄生虫内质网联系起来的功能关系。
The micronemal protein 2 (MIC2) of Toxoplasma gondii shares sequence and structural similarities with a series of adhesive molecules of different apicomplexan parasites. These molecules accumulate, through a yet unknown mechanism, in secretory vesicles (micronemes), which together with tubular and membrane structures form the locomotion and invasion machinery of apicomplexan parasites. Our findings indicated that two conserved motifs placed within the cytoplasmic domain of MIC2 are both necessary and sufficient for targeting proteins to T. gondii micronemes. The first motif is based around the amino acid sequence SYHYY. Database analysis revealed that a similar sequence is present in the cytoplasmic tail of all transmembrane micronemal proteins identified so far in different apicomplexan species. The second signal consists of a stretch of acidic residues, EIEYE. The creation of an artificial tail containing only the two motifs SYHYY and EIEYE in a preserved spacing configuration is sufficient to target the surface protein SAG1 to the micronemes of T. gondii. These findings shed new light on the molecular mechanisms that control the formation of the microneme content and the functional relationship that links these organelles with the endoplasmic reticulum of the parasite.