Characterization of Trypanosoma brucei PEX14 and its role in the import of glycosomal matrix proteins.
It has been shown previously in various organisms that the peroxin PEX14 is a component of a docking complex at the peroxisomal membrane, where it is involved in the import of matrix proteins into the organelle after their synthesis in the cytosol and recognition by a receptor. Here we present a characterization of the Trypanosoma brucei homologue of PEX14. It is shown that the protein is associated with glycosomes, the peroxisome-like organelles of trypanosomatids in which most glycolytic enzymes are compartmentalized. The N-terminal part of the protein binds specifically to TbPEX5, the cytosolic receptor for glycosomal matrix proteins with a peroxisome-targeting signal type 1 (PTS-1). TbPEX14 mRNA depletion by RNA interference results, in both bloodstream-form and procyclic, insect-stage T. brucei, in mislocalization of glycosomal proteins to the cytosol. The mislocalization was observed for different classes of matrix proteins: proteins with a C-terminal PTS-1, a N-terminal PTS-2 and a polypeptide internal I-PTS. The RNA interference experiments also showed that TbPEX14 is essential for the survival of bloodstream-form and procyclic trypanosomes. These data indicate the protein's great potential as a target for selective trypanocidal drugs.
Moyersoen
Juliette
J
Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université Catholique de Louvain, Brussels, Belgium.
Choe
Jungwoo
J
Kumar
Abhinav
A
Voncken
Frank G J
FG
Hol
Wim G J
WG
Michels
Paul A M
PA
D000818:Animals; D002458:Cell Fractionation; D004072:Digitonin / Q000378:metabolism; D007150:Immunohistochemistry; D007202:Indicators and Reagents / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008830:Microbodies / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D000074435:Peroxisome-Targeting Signal 1 Receptor; D021381:Protein Transport / Q000502:physiology*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014346:Trypanosoma brucei brucei / Q000166:cytology / Q000502:physiology*
D007202:Indicators and Reagents; D008565:Membrane Proteins; C468927:PEX14 protein, Trypanosoma brucei; D000074435:Peroxisome-Targeting Signal 1 Receptor; D015800:Protozoan Proteins; D018160:Receptors, Cytoplasmic and Nuclear; D011994:Recombinant Proteins; D004072:Digitonin