The HIV gp41 Fusion Protein Inhibits T-Cell Activation through the Lentiviral Lytic Peptide 2 Motif

Yoel A. Klug, Roland Schwarzer, Etai Rotem, Meital Charni, Alon Nudelman, Andrea Gramatica, Batya Zarmi, Varda Rotter, Yechiel Shai*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The human immunodeficiency virus enters its host cells by membrane fusion, initiated by the gp41 subunit of its envelope protein. gp41 has also been shown to bind T-cell receptor (TCR) complex components, interfering with TCR signaling leading to reduced T-cell activation. This immunoinhibitory activity is suggested to occur during the membrane fusion process and is attributed to various membranotropic regions of the gp41 ectodomain and to the transmembrane domain. Although extensively studied, the cytosolic region of gp41, termed the cytoplasmic tail (CT), has not been examined in the context of immune suppression. Here we investigated whether the CT inhibits T-cell activation in different T-cell models by utilizing gp41-derived peptides and expressed full gp41 proteins. We found that a conserved region of the CT, termed lentiviral lytic peptide 2 (LLP2), specifically inhibits the activation of mouse, Jurkat, and human primary T-cells. This inhibition resulted in reduced T-cell proliferation, gene expression, cytokine secretion, and cell surface expression of CD69. Differential activation of the TCR signaling cascade revealed that CT-based immune suppression occurs downstream of the TCR complex. Moreover, LLP2 peptide treatment of Jurkat and primary human T-cells impaired Akt but not NFκB and ERK1/2 activation, suggesting that immune suppression occurs through the Akt pathway. These findings identify a novel gp41 T-cell suppressive element with a unique inhibitory mechanism that can take place post-membrane fusion.

Original languageAmerican English
Pages (from-to)818-832
Number of pages15
JournalBiochemistry
Volume58
Issue number6
DOIs
StatePublished - 12 Feb 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
Copyright © 2019 American Chemical Society.

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