Struck Nicole S, Herrmann Susann, Langer Christine, Krueger Andreas, Foth Bernardo J, Engelberg Klemens, Cabrera Ana L, Haase Silvia, Treeck Moritz, Marti Matthias, Cowman Alan F, Spielmann Tobias, Gilberger Tim W
Bernhard Nocht Institute for Tropical Medicine, Malaria II, Bernhard-Nocht-Strasse 74, 20359 Hamburg, Germany.
J Cell Sci. 2008 Jul 1;121(Pt 13):2123-9. doi: 10.1242/jcs.021154. Epub 2008 Jun 3.
Plasmodium falciparum, the causative agent of malaria, relies on a complex protein-secretion system for protein targeting into numerous subcellular destinations. Recently, a homologue of the Golgi re-assembly stacking protein (GRASP) was identified and used to characterise the Golgi organisation in this parasite. Here, we report on the presence of a splice variant that leads to the expression of a GRASP isoform. Although the first GRASP protein (GRASP1) relies on a well-conserved myristoylation motif, the variant (GRASP2) displays a different N-terminus, similar to GRASPs found in fungi. Phylogenetic analyses between GRASP proteins of numerous taxa point to an independent evolution of the unusual N-terminus that could reflect unique requirements for Golgi-dependent protein sorting and organelle biogenesis in P. falciparum. Golgi association of GRASP2 depends on the hydrophobic N-terminus that resembles a signal anchor, leading to a unique mode of Golgi targeting and membrane attachment.
恶性疟原虫是疟疾的病原体,它依靠一种复杂的蛋白质分泌系统将蛋白质靶向输送到众多亚细胞目的地。最近,高尔基体重新组装堆叠蛋白(GRASP)的一个同源物被鉴定出来,并用于表征这种寄生虫中的高尔基体组织。在此,我们报告了一种剪接变体的存在,该变体导致一种GRASP异构体的表达。尽管第一个GRASP蛋白(GRASP1)依赖于一个保守的肉豆蔻酰化基序,但该变体(GRASP2)显示出不同的N端,类似于在真菌中发现的GRASP。众多分类群的GRASP蛋白之间的系统发育分析表明,这种不寻常的N端是独立进化的,这可能反映了恶性疟原虫中高尔基体依赖性蛋白质分选和细胞器生物发生的独特需求。GRASP2与高尔基体的结合取决于类似于信号锚的疏水N端,导致一种独特的高尔基体靶向和膜附着模式。