Open AccessThe Longin Domain Regulates the Steady-State Dynamics of Sec22 in Plasmodium falciparum
Author(s) -
Lawrence Ayong,
Avanthi Raghavan,
Timothy Schneider,
Theodore F. Taraschi,
David A. Fidock,
Debopam Chakrabarti
Publication year - 2009
Publication title -
eukaryotic cell
Language(s) - English
Resource type - Journals
eISSN - 1535-9778
pISSN - 1535-9786
DOI - 10.1128/ec.00092-09
Subject(s) - endoplasmic reticulum , biology , plasmodium falciparum , golgi apparatus , microbiology and biotechnology , transport protein , protein domain , membrane protein , biochemistry , gene , membrane , malaria , immunology
The specificity of vesicle-mediated transport is largely regulated by the membrane-specific distribution of SNARE (solubleN -ethylmaleimide-sensitive factor attachment protein receptor) proteins. However, the signals and machineries involved in SNARE protein targeting to the respective intracellular locations are not fully understood. We have identified a Sec22 ortholog inPlasmodium falciparum (PfSec22) that contains an atypical insertion of thePlasmodium export element within the N-terminal longin domain. This Sec22 protein partially associates with membrane structures in the parasitized erythrocytes when expressed under the control of the endogenous promoter element. Our studies indicate that the atypical longin domain contains signals that are required for both endoplasmic reticulum (ER)/Golgi apparatus recycling of PfSec22 and partial export beyond the ER/Golgi apparatus interface. ER exit of PfSec22 is regulated by motifs within the α3 segment of the longin domain, whereas the recycling and export signals require residues within the N-terminal hydrophobic segment. Our data suggest that the longin domain of PfSec22 exhibits major differences from the yeast and mammalian orthologs, perhaps indicative of a novel mechanism for Sec22 trafficking in malaria parasites.