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

Sophie Arthur

former Science Communications Officer MRC LMS

Formerly a stem cell biologist, Sophie has since moved into science communication working at the MRC LMS. She also writes an award winning science and education blog Soph talks science.

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• 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