Identification of a novel post-translational modification in Plasmodium falciparum: protein sumoylation in different cellular compartments.
SUMO (Small Ubiquitin-like MOdifier) conjugation is a post-translational modification implicated in a variety of cellular functions including transcriptional regulation, nuclear location and signal transduction. Sumoylation, although conserved and vital in eukaryotes, has not been studied in malaria parasites. Here, we identify SUMO conjugation of blood stage parasites of Plasmodium falciparum. Antibodies raised against synthetic peptides of the plasmodial SUMO orthologue PfSUMO, a 100-amino-acid protein, reacted with distinctive subcellular compartments of the parasitized erythrocyte during blood stage development. Anti-PfSUMO stains the nucleus and parasite cytoplasm. We also found antibody reactivity in the host cell cytoplasm with the parasite-derived structures called Maurer's clefts. Anti-PfSUMO reacts in Western blot with a number of blood stage proteins ranging from approximately 40-250 kDa. Parasites expressing FLAG-tagged PfSUMO gave similar results in Immunofluorescence assay and Western blots. In addition, we show that anti-PfSUMO identified PfSir2, a telomere-associated nuclear protein involved in var gene silencing, as a target for sumoylation. Furthermore, LC-MS/MS analysis of a two-step immunoprecipitation (IP) with anti-FLAG and anti-PfSUMO antibodies reveals a number of putative P. falciparum sumoylated proteins. Our results imply that SUMO conjugation has an essential function in a number of different biological processes in P. falciparum.
Issar
Neha
N
Institut Pasteur- CNRS URA 2581, Biology of Host-Parasite Interactions Unit, F75724 Paris, France.
Roux
Emeric
E
Mattei
Denise
D
Scherf
Artur
A
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000737:chemistry; D003593:Cytoplasm / Q000737:chemistry; D004912:Erythrocytes / Q000469:parasitology; D019085:Fluorescent Antibody Technique, Direct; D052940:Merozoites / Q000737:chemistry / Q000502:physiology; D008954:Models, Biological; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000737:chemistry / Q000502:physiology*; D011499:Protein Processing, Post-Translational; D015800:Protozoan Proteins / Q000378:metabolism*; D016415:Sequence Alignment; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism*
D015800:Protozoan Proteins; D025841:Small Ubiquitin-Related Modifier Proteins