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The divergent Golgi‐localizing trypanosome ARF1 has a central role in endocytosis
Author(s) -
Price Helen Philippa,
Goulding David,
Stark Meg,
Smith Deborah
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb63-a
Subject(s) - golgi apparatus , endocytosis , microbiology and biotechnology , biology , copi , transport protein , endosome , adp ribosylation factor , trypanosoma brucei , secretory pathway , cell , endoplasmic reticulum , biochemistry , gene , intracellular
ADP ribosylation factors (ARFs) have essential roles in protein trafficking and membrane dynamics in eukaryotic cells. ARF1 mediates vesicle formation at the Golgi apparatus whereas the plasma membrane protein ARF6 regulates actin rearrangement and endocytosis. We have characterized the ARF1 homologue (TbARF1) in the ancient eukaryotic parasite, Trypanosoma brucei . Unexpectedly, this protein shares characteristics with both ARF1 and ARF6, suggesting that it may be a single progenitor of these 2 mammalian proteins. TbARF1 is Golgi‐localized in parasites but when expressed in human cells, the protein associates instead with the plasma membrane. RNA interference has been used to monitor the effects of downregulating TbARF1 expression in parasites. Analyses by immunofluorescence, pulse‐chase labelling and electron microscopy show that the protein has an essential role in endocytosis but is not required for Golgi integrity. Our current data indicate that TbARF1 is functionally similar to ARF6 despite its contradicting localization in the cell and may represent a previously undescribed class of ARFs in protozoa. This work is funded by the Wellcome Trust