Proteome analysis of rhoptry-enriched fractions isolated from Plasmodium merozoites.
The rhoptries of Plasmodium species participate in merozoite invasion and modification of the host erythrocyte. However, only a few rhoptry proteins have been identified using conventional gene identification protocols. To investigate the protein organization of this organelle and to identify new rhoptry proteins, merozoite rhoptries from three different Plasmodium rodent species were enriched by sucrose density gradient fractionation, and subjected to proteome analysis using multidimensional protein identification technology (MudPIT); 148 proteins were identified. To distinguish abundant cellular contaminants from bona fide organellar proteins, a differential analysis comparing the proteins in the rhoptry-enriched fractions to proteins identified from whole cell lysates of P. berghei mixed asexual blood stages was undertaken. In addition, the proteins detected were analyzed for the presence of transmembrane domains, secretory signal peptide, cell adhesion motifs, and/or rhoptry-specific tyrosine-sorting motifs. Combining the differential analysis and bioinformatic approaches, a set of 36 proteins was defined as being potentially located to the Plasmodium rhoptries. Among these potential rhoptry proteins were homologues of known rhoptry proteins, proteases, and enzymes involved in lipid metabolism. Molecular characterization and understanding of the supramolecular organization of these novel potential rhoptry proteins may assist in the identification of new intervention targets for the asexual blood stages of malaria.
Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, Ohio 44115, USA. ilibot@hotmail.com
Tobili Y
TY
Sam-Yellowe
Laurence
L
Florens
Tongmin
T
Wang
J Dale
JD
Raine
Daniel J
DJ
Carucci
Robert
R
Sinden
John R
JR
Yates
D000818:Animals; D002458:Cell Fractionation; D030562:Databases, Protein; D010450:Endopeptidases / Q000378:metabolism; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000032:analysis; D010447:Peptide Hydrolases / Q000032:analysis / Q000378:metabolism; D010961:Plasmodium / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010962:Plasmodium berghei / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016788:Plasmodium chabaudi / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010967:Plasmodium yoelii / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals / Q000235:genetics; D020543:Proteome / Q000032:analysis* / Q000378:metabolism; D015800:Protozoan Proteins / Q000032:analysis* / Q000378:metabolism; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics
D008565:Membrane Proteins; D021382:Protein Sorting Signals; D020543:Proteome; D015800:Protozoan Proteins; D010450:Endopeptidases; D010447:Peptide Hydrolases