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Early assembly step of a retroviral envelope glycoprotein: analysis using a dominant negative assay.
- Source :
-
The Journal of cell biology [J Cell Biol] 1999 Apr 05; Vol. 145 (1), pp. 57-68. - Publication Year :
- 1999
-
Abstract
- As for most integral membrane proteins, the intracellular transport of retroviral envelope glycoproteins depends on proper folding and oligomeric assembly in the ER. In this study, we considered the hypothesis that a panel of 22 transport-defective mutants of the human T cell leukemia virus type 1 envelope glycoprotein might be defective in ER assembly. Upon cell cotransfection with wild-type envelope, however, the vast majority of these transport-defective mutants (21 of 22) exerted a specific trans-dominant negative effect. This effect was due to random dimerization of the mutated and wild-type glycoproteins that prevented the intracellular transport of the latter. This unexpected result suggests that association of glycoprotein monomers precedes the completion of folding. The only mutation that impaired this early assembly was located at the NH2 terminus of the protein. COOH-terminally truncated, soluble forms of the glycoprotein were also trans-dominant negative provided that their NH2 terminus was intact. The leucine zipper-like domain, although involved in oligomerization of the envelope glycoproteins at the cell surface, did not contribute to their intracellular assembly. We propose that, at a step subsequent to translation, but preceding complete folding of the monomers, glycoproteins assemble via their NH2-terminal domains, which, in turn, permits their cooperative folding.
- Subjects :
- Amino Acid Substitution
Animals
Biological Transport
COS Cells
Dimerization
Gene Products, env chemistry
Gene Products, env genetics
Glycosylation
Golgi Apparatus metabolism
HeLa Cells
Humans
Leucine Zippers
Endoplasmic Reticulum metabolism
Gene Products, env biosynthesis
Genes, Dominant
Genes, env
Human T-lymphotropic virus 1 genetics
Human T-lymphotropic virus 2 genetics
Protein Conformation
Protein Folding
Protein Processing, Post-Translational
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9525
- Volume :
- 145
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- The Journal of cell biology
- Publication Type :
- Academic Journal
- Accession number :
- 10189368
- Full Text :
- https://doi.org/10.1083/jcb.145.1.57