Gp41 dynamically interacts with the TCR in the immune synapse and promotes early T cell activation

Oren Yakovian,Julia Sajman,Yair Razvag,Eilon Sherman,Yair Neve-Oz,Roland Schwarzer,Andreas Herrmann

doi:10.1038/s41598-018-28114-5

Oren Yakovian, Julia Sajman + Show 5 more

Open Access

https://doi.org/10.1038/s41598-018-28114-5

Copy DOI

Abstract

The HIV-1 glycoprotein gp41 critically mediates CD4+ T-cell infection by HIV-1 during viral entry, assembly, and release. Although multiple immune-regulatory activities of gp41 have been reported, the underlying mechanisms of these activities remain poorly understood. Here we employed multi-colour single molecule localization microscopy (SMLM) to resolve interactions of gp41 proteins with cellular proteins at the plasma membrane (PM) of fixed and live CD4+ T-cells with resolution of ~20–30 nm. We observed that gp41 clusters dynamically associated with the T cell antigen receptor (TCR) at the immune synapse upon TCR stimulation. This interaction, confirmed by FRET, depended on the virus clone, was reduced by the gp41 ectodomain in tight contacts, and was completely abrogated by mutation of the gp41 transmembrane domain. Strikingly, gp41 preferentially colocalized with phosphorylated TCRs at the PM of activated T-cells and promoted TCR phosphorylation. Gp41 expression also resulted in enhanced CD69 upregulation, and in massive cell death after 24–48 hrs. Our results shed new light on HIV-1 assembly mechanisms at the PM of host T-cells and its impact on TCR stimulation.

Highlights

Viruses interact with a manifold of host cell components in order to facilitate different steps of the viral life cycle
We found that the transmembrane domain (TMD) of gp[41] mediates its interaction with the T cell antigen receptor (TCR) at the plasma membrane (PM) of activated and
We found that these two proteins showed clusters that closely localized, but did not overlap (Fig. 5A), yielding extent of mixing (EOM) and standardized bivariate PCF (SBPCF) statistics that approached the model of no interaction (Figs 5C and S2K)

Summary

Introduction

Viruses interact with a manifold of host cell components in order to facilitate different steps of the viral life cycle. The envelope protein (Env) of HIV-1 has been shown to mediate host cell binding and the fusion between cellular and viral membrane. Viral assembly and budding depends on gp[41] aggregation at the plasma membrane (PM)[2] This assembly process is regulated by both viral and cellular factors[3], it is yet unclear what mechanism is enabling efficient interactions between the viral structural proteins on the host cell surface in the final stages of virus genesis[3]. A critical limitation of studying viral assembly concerns the small, nanometer sized nanoclusters of viral and cellular proteins that are involved in this process[7] This prevents the study of viral assembly in intact cells using diffraction-limited light microscopy. Our results shed new light on the assembly mechanism of gp[41] at the PM of T cells and may indicate new ways for intervening with T cell signalling, viral budding and repeated HIV-1 infection

Methods

Results

Conclusion