Organised Attack

T cells – a type of white blood cell – circulate around our bodies until they encounter their specific target ‘foreign’ molecule or antigen on antigen-presenting cells. When first doing the rounds, T cells aren’t primed and ready to leap into action, they need to be activated Activation happens by two of their proteins working together: the T cell receptor (TCR) and CD28, which form a stable connection between the T cell and the antigen-presenting cell. Both proteins then cluster on the T cell membrane. Unlike those of the TCR, the details of CD28 clustering during T cell activation are less clear. Now, using advanced microscopy called 3D CLEM, researchers have shown that another T cell protein called SNX9 (magenta) plays a key role organising and contorting the membrane at CD28 clusters (cyan) pulling them close to the TCR on the membrane (white) to activate the T cell.

Written by Sophie Arthur

Image from work by Manuela Ecker and colleagues

EMBL Australia Node in Single Molecule Science, School of Medical Sciences and the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Sydney, Australia

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in eLife, January 2022