科研之友
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摘要
Plasmodium falciparum, similar to many other apicomplexan parasites, contains an apicoplast, a plastid organelle of secondary endosymbiotic origin. Nuclear-encoded proteins are posttranslationally transported to the apicoplast via the endoplasmic reticulum. However, it has long been a matter of contention if the Golgi also plays a role in this process. In this study, we show that trafficking to the apicoplast occurs via the Golgi as an intermediate compartment. Our data suggest that the Plasmodium Golgi has an important function as a protein sorting compartment. %26lt;br%26gt;Plasmodium falciparum, similar to many other apicomplexan parasites, contains an apicoplast, a plastid organelle of secondary endosymbiotic origin. Nuclear-encoded proteins are targeted to the apicoplast by a bipartite topogenic signal consisting of (i) an endoplasmic reticulum (ER)-type N-terminal secretory signal peptide, followed by (ii) a plant-like transit peptide. Although the signals responsible for transport of most proteins to the apicoplast are well described, the route of trafficking from the ER to the outermost apicoplast membrane is still a matter of debate. Current models of trafficking to the apicoplast suggest that proteins destined for this organelle are, on entry into the lumen of the ER, diverted from the default secretory pathway to a specialized vesicular system which carries proteins directly from the ER to the outer apicoplast membrane. Here, we have re-examined this trafficking pathway. By titrating wild-type and mutant apicoplast transit peptides against different ER retrieval sequences and studying protein transport in a brefeldin A-resistant parasite line, we generated data which suggest a direct involvement of the Golgi in traffic of soluble proteins to the P. falciparum apicoplast.
- 出版日期2014-12
