Systems-level conservation of the proximal TCR signaling network of mice and humans

Abstract

We exploited traceable gene tagging in primary human T cells to establish the composition and dynamics of seven canonical TCR-induced protein signaling complexes (signalosomes) using affinity purification coupled with mass spectrometry (AP-MS). It unveiled how the LAT adaptor assembles higher-order molecular condensates and revealed that the proximal TCR-signaling network has a high degree of qualitative and quantitative conservation between human CD4+ and CD8+ T cells. Such systems-level conservation also extended across human and mouse T cells and unexpectedly encompassed protein–protein interaction stoichiometry. Independently of evolutionary considerations, our study suggests that a drug targeting the proximal TCR signaling network should behave similarly when applied to human and mouse T cells. However, considering that signaling differences likely exist between the distal TCR-signaling pathway of human and mouse, our fast-track AP-MS approach should be favored to determine the mechanism of action of drugs targeting human T cell activation. An opportunity is illustrated here using an inhibitor of the LCK protein tyrosine kinase as a proof-of-concept.

Discrete LAT condensates encode antigen information from single pMHC:TCR binding events

“…LAT condensation occurs abruptly, but after a relatively long delay time ( s in this trace; mean delay is s). The LAT condensates are self-limiting with a mean lifetime of ; a similar limiting lifetime for LAT condensates has recently been estimated indirectly from mass spectrometry studies 73 on cell populations. In some cases (e.g.…”

Negative intracellular regulators of T-cell receptor (TCR) signaling as potential antitumor immunotherapy targets

“… 139 And for instance, the iICP, HPK1 binds to SLP-76 on TCR triggering with similar kinetics in human expanded CD4 + and CD8 + T cells. 139 …”

“…However, the composition and dynamics of the proximal TCR signal transduction protein network seems to be largely conserved between human expanded CD4 + and CD8 + T cells. 139 And for instance, the iICP, HPK1 binds to SLP-76 on TCR triggering with similar kinetics in human expanded CD4 + and CD8 + T cells. 139 ACT therapy for cancer treatment is rapidly expanding notably after the clinical acceptance of CAR-T cells.…”

“…139 And for instance, the iICP, HPK1 binds to SLP-76 on TCR triggering with similar kinetics in human expanded CD4 + and CD8 + T cells. 139 ACT therapy for cancer treatment is rapidly expanding notably after the clinical acceptance of CAR-T cells.…”

ZAP70 holds the key to kinetic proofreading for TCR ligand discrimination

“…The study by Voisine et al 2 answers a long-standing question of how kinetic proofreading is executed through biochemical processes downstream of the TCR. It will also serve, along with previous reports examining TCR-induced phosphorylation and interaction networks in primary murine and human CD4 + T cells [10][11][12] , as a useful resource to understand the signalling processes that cumulatively drive T cell activation. Indeed, several other novel interactions are identified here 2 as occurring at the TCR, such as WRNIP1 and ANKRD13A, and the role of these proteins in TCR signalling will need to be characterized.…”