Open AccessAn Unusual ERAD-Like Complex Is Targeted to the Apicoplast of Plasmodium falciparum
Author(s) -
Simone Spork,
Jan A. Hiss,
Katharina Mandel,
Maik S. Sommer,
Taco W. A. Kooij,
Trang T. T. Chu,
Gisbert Schneider,
Uwe G. Maier,
Jude M. Przyborski
Publication year - 2009
Publication title -
eukaryotic cell
Language(s) - English
Resource type - Journals
eISSN - 1535-9778
pISSN - 1535-9786
DOI - 10.1128/ec.00083-09
Subject(s) - apicoplast , biology , endoplasmic reticulum associated protein degradation , plastid , plasmodium falciparum , endoplasmic reticulum , translocon , microbiology and biotechnology , transport protein , biochemistry , membrane protein , unfolded protein response , gene , malaria , chloroplast , membrane , immunology
Many apicomplexan parasites, includingPlasmodium falciparum , harbor a so-called apicoplast, a complex plastid of red algal origin which was gained by a secondary endosymbiotic event. The exact molecular mechanisms directing the transport of nuclear-encoded proteins to the apicoplast ofP. falciparum are not well understood. Recently, in silico analyses revealed a second copy of proteins homologous to components of the endoplasmic reticulum (ER)-associated protein degradation (ERAD) system in organisms with secondary plastids, including the malaria parasiteP. falciparum . These proteins are predicted to be endowed with an apicoplast targeting signal and are suggested to play a role in the transport of nuclear-encoded proteins to the apicoplast. Here, we have studied components of this ERAD-derived putative preprotein translocon complex in malaria parasites. Using transfection technology coupled with fluorescence imaging techniques we can demonstrate that the N terminus of several ERAD-derived components targets green fluorescent protein to the apicoplast. Furthermore, we confirm that full-length PfsDer1-1 and PfsUba1 (homologues of yeast ERAD components) localize to the apicoplast, where PfsDer1-1 tightly associates with membranes. Conversely, PfhDer1-1 (a host-specific copy of the Der1-1 protein) localizes to the ER. Our data suggest that ERAD components have been “rewired” to provide a conduit for protein transport to the apicoplast. Our results are discussed in relation to the nature of the apicoplast protein transport machinery.