Membrane transporters in the relict plastid of malaria parasites
Publication Year 2006-06-20, Volume 103, Issue #25, Page 9572-9577
- Journal Title
- PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
- Publication Type
- Journal Article
- Malaria parasites contain a nonphotosynthetic plastid homologous to chloroplasts of plants. The parasite plastid synthesizes fatty acids, heme, iron sulfur clusters and isoprenoid precursors and is indispensable, making it an attractive target for antiparasite drugs. How parasite plastid biosynthetic pathways are fuelled in the absence of photosynthetic capture of energy and carbon was not clear. Here, we describe a pair of parasite transporter proteins, PfiTPT and PfoTPT, that are homologues of plant chloroplast innermost membrane transporters responsible for moving phosphorylated C3, C5, and C6 compounds across the plant chloroplast envelope. PfiTPT is shown to be localized in the innermost membrane of the parasite plastid courtesy of a cleavable N-terminal targeting sequence. PfoTPT lacks such a targeting sequence, but is shown to localize in the outermost parasite plastid membrane with its termini projecting into the cytosol. We have identified these membrane proteins in the parasite plastid and determined membrane orientation for PfoTPT. PfiTPT and PfoTPT are proposed to act in tandem to transport phosphorylated C3 compounds from the parasite cytosol into the plastid. Thus, the transporters could shunt glycolytic derivatives of glucose scavenged from the host into the plastid providing carbon, reducing equivalents and ATP to power the organelle.
- NATL ACAD SCIENCES
- PLASMODIUM-FALCIPARUM; TOXOPLASMA-GONDII; APICOMPLEXAN PARASITES; GENOME SEQUENCE; DRUG TARGETS; APICOPLAST; PROTEINS; PATHWAY; IDENTIFICATION; BIOSYNTHESIS
- Publisher's Version
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Creation Date: 2006-06-20 12:00:00Last Modified: 0001-01-01 12:00:00