A gene-family encoding small exported proteins is conserved across Plasmodium genus
A gene-family encoding small exported proteins is conserved across Plasmodium genus
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DOI：
10.1016/s0166-6851(02)00275-x
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发表时间：
2003-02-01
影响因子：
1.5
通讯作者：
Ponzi, M
中科院分区：
文献类型：
--
作者：
Birago, C;Albanesi, V;Ponzi, M
已鉴定出一个基因家族，命名为Sep，编码在疟原虫物种中保守的小输出蛋白。SEP蛋白(13-16 kDa)在NH2末端含有一个预测的信号肽，在NH2末端有一个内部疏水区，在羧基末端有一个多态的低复杂性区域。伯氏疟原虫家族的成员之一PbSep1编码一种完整的膜蛋白，在整个红细胞周期中表达。免疫定位结果表明，直到分裂早期，PbSEP1定位于寄生液泡的膜上，而在分裂晚期，它重新定位在联合体内的结构中。红细胞破裂后，在游离裂殖子中仍可检测到PbSEP1，这表明它参与了寄生虫入侵的早期步骤。恶性疟原虫中Sep-家族的7名成员已被确认。其中两个与先前报道的早期转录膜蛋白家族(Etramp)中的基因序列相对应。本工作显示的SEP家族的结构、功能和系统发育特征取代了以前的分类。PfSEP蛋白被输出到寄生虫膜之外，并在入侵后早期转移到与囊泡状结构相关的宿主细胞室。共定位结果表明，在滋养体阶段，PfSEP特异的荧光与Pf332重叠，Pf332是一种与毛雷尔裂隙相关的蛋白质，毛雷尔裂隙是寄生虫红细胞胞浆中的膜结构，最可能参与寄生虫蛋白的运输。将SEP蛋白定向到Rberghei的液泡膜或恶性疟原虫的寄主细胞室所需的特定信号仍有待确定。(C)2002 Elsevier Science B.V.保留所有权利。
A gene-family, named sep, encoding small exported proteins conserved across Plasmodium species has been identified. SEP proteins (13-16 kDa) contain a predicted signal peptide at the NH2-terminus, an internal hydrophobic region and a polymorphic, low-complexity region at the carboxy-terminus. One member of the Plasmodium berghei family, Pbsep1, encodes an integral membrane protein expressed along the entire erythrocytic cycle. Immunolocalisation results indicated that PbSEP1 is targeted to the membrane of the parasitophorous vacuole up to the early phases of schizogony, while, in late schizonts, it re-locates in structures within the syncitium. After erythrocyte rupture, PbSEP1 is still detectable in free merozoites thus suggesting its involvement in the early steps of parasite invasion. Seven members of the sep-family in Plasmodium falciparum have been identified. Two of them correspond to previously reported gene sequences included in a family of early transcribed membrane proteins (etramp). Structural, functional and phylogenetic features of the sep family, shown in the present work, supercede this previous classification. PfSEP proteins are exported beyond the parasite membrane and translocated, early after invasion, to the host cell compartment in association with vesicle-like structures. Colocalisation results indicated that PfSEP-specific fluorescence overlaps, at the stage of trophozoite, with that of Pf332, a protein associated with Maurer's clefts, membranous structures in the cytosol of parasitised red blood cells, most probably involved in trafficking of parasite proteins. The specific signals necessary to direct SEP proteins to the vacuolar membrane in R berghei or to the host cell compartment in P. falciparum remain to be determined. (C) 2002 Elsevier Science B.V. All rights reserved.