Journal article
ARF1 regulates Nef-induced CD4 degradation.
- Fauré J Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland.
- Stalder R
- Borel C
- Sobo K
- Piguet V
- Demaurex N
- Gruenberg J
- Trono D
- 2004-06-19
Published in:
- Current biology : CB. - 2004
ADP-Ribosylation Factor 1
Animals
CD4 Antigens
Cells, Cultured
Coated Pits, Cell-Membrane
Cricetinae
Endocytosis
Endosomes
Fluorescent Antibody Technique
Gene Products, nef
Genetic Vectors
HIV
HeLa Cells
Humans
Microscopy, Confocal
Mutation
Plasmids
Precipitin Tests
Ubiquitin-Protein Ligases
Viral Fusion Proteins
nef Gene Products, Human Immunodeficiency Virus
English
BACKGROUND
The HIV Nef protein downregulates CD4 through sequential connection with clathrin-coated pits and the COP1 coatomer, resulting in accelerated endocytosis and lysosomal targeting.
RESULTS
Here we report that the small GTPase ARF1 controls the Nef-induced, COP-mediated late-endosomal targeting of CD4. We find that Nef binds ARF1 directly and can recruit the GTPase onto endosomal membranes. Furthermore, a complex comprising Nef, ARF1, and betaCOP can be immunoprecipitated from cells expressing the viral protein. Residues in a C-terminal loop of the viral protein facilitate both these interactions and the targeting of Nef and CD4 to acidic late endosomes, whereas other residues primarily involved in mediating CD4 endocytosis are dispensable for this process. Finally, a dominant-negative ARF1 mutant blocks the migration of the Nef-CD4 complex to lysosomes.
CONCLUSIONS
Our results support a model in which ARF1 is the immediate downstream partner of Nef for CD4 lysosomal targeting.
The HIV Nef protein downregulates CD4 through sequential connection with clathrin-coated pits and the COP1 coatomer, resulting in accelerated endocytosis and lysosomal targeting.
RESULTS
Here we report that the small GTPase ARF1 controls the Nef-induced, COP-mediated late-endosomal targeting of CD4. We find that Nef binds ARF1 directly and can recruit the GTPase onto endosomal membranes. Furthermore, a complex comprising Nef, ARF1, and betaCOP can be immunoprecipitated from cells expressing the viral protein. Residues in a C-terminal loop of the viral protein facilitate both these interactions and the targeting of Nef and CD4 to acidic late endosomes, whereas other residues primarily involved in mediating CD4 endocytosis are dispensable for this process. Finally, a dominant-negative ARF1 mutant blocks the migration of the Nef-CD4 complex to lysosomes.
CONCLUSIONS
Our results support a model in which ARF1 is the immediate downstream partner of Nef for CD4 lysosomal targeting.
- Language
-
- English
- Open access status
- closed
- Identifiers
-
- DOI 10.1016/j.cub.2004.06.021
- PMID 15202998
- Persistent URL
- https://sonar.ch/global/documents/230496
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