Positive feedback between the T cell kinase Zap70 and its substrate LAT acts as a clustering-dependent signaling switch.

TitlePositive feedback between the T cell kinase Zap70 and its substrate LAT acts as a clustering-dependent signaling switch.
Publication TypeJournal Article
Year of Publication2021
AuthorsDine, E, Reed, EH, Toettcher, JE
JournalCell Rep
Volume35
Issue12
Pagination109280
Date Published2021 06 22
ISSN2211-1247
KeywordsAdaptor Proteins, Signal Transducing, Animals, Calcium Signaling, Cluster Analysis, Enzyme Activation, Feedback, Physiological, Humans, Jurkat Cells, Light, Membrane Proteins, Mice, Models, Biological, NIH 3T3 Cells, Optogenetics, Phosphorylation, Protein Multimerization, Signal Transduction, Substrate Specificity, ZAP-70 Protein-Tyrosine Kinase
Abstract

<p>Protein clustering is pervasive in cell signaling, yet how signaling from higher-order assemblies differs from simpler forms of molecular organization is still poorly understood. We present an optogenetic approach to switch between oligomers and heterodimers with a single point mutation. We apply this system to study signaling from the kinase Zap70 and its substrate linker for activation of T cells (LAT), proteins that normally form membrane-localized condensates during T cell activation. We find that fibroblasts expressing synthetic Zap70:LAT clusters activate downstream signaling, whereas one-to-one heterodimers do not. We provide evidence that clusters harbor a positive feedback loop among Zap70, LAT, and Src-family kinases that binds phosphorylated LAT and further activates Zap70. Finally, we extend our optogenetic approach to the native T cell signaling context, where light-induced LAT clustering is sufficient to drive a calcium response. Our study reveals a specific signaling function for protein clusters and identifies a biochemical circuit that robustly senses protein oligomerization state.</p>

DOI10.1016/j.celrep.2021.109280
Alternate JournalCell Rep
PubMed ID34161759
PubMed Central IDPMC8292983
Grant ListDP2 EB024247 / EB / NIBIB NIH HHS / United States
F31 AI145218 / AI / NIAID NIH HHS / United States
T32 GM007388 / GM / NIGMS NIH HHS / United States