Sequence requirements for the export of the Plasmodium falciparum Maurer's clefts protein REX2.
A short motif termed Plasmodium export element (PEXEL) or vacuolar targeting signal (VTS) characterizes Plasmodium proteins exported into the host cell. These proteins mediate host cell modifications essential for parasite survival and virulence. However, several PEXEL-negative exported proteins indicate that the currently predicted malaria exportome is not complete and it is unknown whether and how these proteins relate to PEXEL-positive export. Here we show that the N-terminal 10 amino acids of the PEXEL-negative exported protein REX2 (ring-exported protein 2) are necessary for its targeting and that a single-point mutation in this region abolishes export. Furthermore we show that the REX2 transmembrane domain is also essential for export and that together with the N-terminal region it is sufficient to promote export of another protein. An N-terminal region and the transmembrane domain of the unrelated PEXEL-negative exported protein SBP1 (skeleton-binding protein 1) can functionally replace the corresponding regions in REX2, suggesting that these sequence features are also present in other PEXEL-negative exported proteins. Similar to PEXEL proteins we find that REX2 is processed, but in contrast, detect no evidence for N-terminal acetylation.
Haase
Silvia
S
Bernhard Nocht Institute for Tropical Medicine, Malaria II, 20359 Hamburg, Germany.
Herrmann
Susann
S
Grüring
Christof
C
Heiber
Arlett
A
Jansen
Pascal W
PW
Langer
Christine
C
Treeck
Moritz
M
Cabrera
Ana
A
Bruns
Caroline
C
Struck
Nicole S
NS
Kono
Maya
M
Engelberg
Klemens
K
Ruch
Ulrike
U
Stunnenberg
Hendrik G
HG
Gilberger
Tim-Wolf
TW
Spielmann
Tobias
T
D000595:Amino Acid Sequence; D000818:Animals; D004912:Erythrocytes / Q000469:parasitology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000235:genetics / Q000378:metabolism*; D017354:Point Mutation; D021381:Protein Transport; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017384:Sequence Deletion
D008565:Membrane Proteins; D015800:Protozoan Proteins