The mTORC1-4E-BP-eIF4E axis controls de novo Bcl6 protein synthesis in T cells and systemic autoimmunity. Academic Article uri icon

Overview

abstract

  • Post-transcriptional modifications can control protein abundance, but the extent to which these alterations contribute to the expression of T helper (TH) lineage-defining factors is unknown. Tight regulation of Bcl6 expression, an essential transcription factor for T follicular helper (TFH) cells, is critical as aberrant TFH cell expansion is associated with autoimmune diseases, such as systemic lupus erythematosus (SLE). Here we show that lack of the SLE risk variant Def6 results in deregulation of Bcl6 protein synthesis in T cells as a result of enhanced activation of the mTORC1-4E-BP-eIF4E axis, secondary to aberrant assembly of a raptor-p62-TRAF6 complex. Proteomic analysis reveals that this pathway selectively controls the abundance of a subset of proteins. Rapamycin or raptor deletion ameliorates the aberrant TFH cell expansion in mice lacking Def6. Thus deregulation of mTORC1-dependent pathways controlling protein synthesis can result in T-cell dysfunction, indicating a mechanism by which mTORC1 can promote autoimmunity.Excessive expansion of the T follicular helper (TFH) cell pool is associated with autoimmune disease and Def6 has been identified as an SLE risk variant. Here the authors show that Def6 limits proliferation of TFH cells in mice via alteration of mTORC1 signaling and inhibition of Bcl6 expression.

publication date

  • August 15, 2017

Research

keywords

  • Autoimmunity
  • Carrier Proteins
  • Eukaryotic Initiation Factor-4E
  • Lupus Erythematosus, Systemic
  • Mechanistic Target of Rapamycin Complex 1
  • Phosphoproteins
  • Proto-Oncogene Proteins c-bcl-6
  • T-Lymphocytes, Helper-Inducer

Identity

PubMed Central ID

  • PMC5557982

Scopus Document Identifier

  • 85027492347

Digital Object Identifier (DOI)

  • 10.1074/mcp.M113.031591

PubMed ID

  • 28811467

Additional Document Info

volume

  • 8

issue

  • 1