Systematic analysis of intracellular trafficking motifs located within the cytoplasmic domain of simian immunodeficiency virus glycoprotein gp41

Thomas S. Postler, Jacqueline G. Bixby, Ronald Charles Desrosiers, Eloísa Yuste, Zandrea Ambrose

Research output: Contribution to journalArticle

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Abstract

Previous studies have shown that truncation of the cytoplasmic-domain sequences of the simian immunodeficiency virus (SIV) envelope glycoprotein (Env) just prior to a potential intracellular-trafficking signal of the sequence YIHF can strongly increase Env protein expression on the cell surface, Env incorporation into virions and, at least in some contexts, virion infectivity. Here, all 12 potential intracellulartrafficking motifs (YXXW or LL/LI/IL) in the gp41 cytoplasmic domain (gp41CD) of SIVmac239 were analyzed by systematic mutagenesis. One single and 7 sequential combination mutants in this cytoplasmic domain were characterized. Cell-surface levels of Env were not significantly affected by any of the mutations. Most combination mutations resulted in moderate 3- To 8-fold increases in Env incorporation into virions. However, mutation of all 12 potential sites actually decreased Env incorporation into virions. Variant forms with 11 or 12 mutated sites exhibited 3-fold lower levels of inherent infectivity, while none of the other single or combination mutations that were studied significantly affected the inherent infectivity of SIVmac239. These minor effects of mutations in trafficking motifs form a stark contrast to the strong increases in cell-surface expression and Env incorporation which have previously been reported for large truncations of gp41CD. Surprisingly, mutation of potential trafficking motifs in gp41CD of SIVmac316, which differs by only one residue from gp41CD of SIVmac239, effectively recapitulated the increases in Env incorporation into virions observed with gp41CD truncations. Our results indicate that increases in Env surface expression and virion incorporation associated with truncation of SIVmac239 gp41CD are not fully explained by loss of consensus trafficking motifs.

Original languageEnglish (US)
Article numbere114753
JournalPLoS One
Volume9
Issue number12
DOIs
StatePublished - Dec 5 2014

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Simian immunodeficiency virus
Simian Immunodeficiency Virus
Viruses
virion
Virion
glycoproteins
Glycoproteins
env Gene Products
mutation
Mutation
pathogenicity
Mutagenesis
Protein Sorting Signals
cells
signal peptide
mutagenesis
protein synthesis
mutants

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Systematic analysis of intracellular trafficking motifs located within the cytoplasmic domain of simian immunodeficiency virus glycoprotein gp41. / Postler, Thomas S.; Bixby, Jacqueline G.; Desrosiers, Ronald Charles; Yuste, Eloísa; Ambrose, Zandrea.

In: PLoS One, Vol. 9, No. 12, e114753, 05.12.2014.

Research output: Contribution to journalArticle

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