Abstract
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.
Original language | English (US) |
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Article number | 109280 |
Journal | Cell Reports |
Volume | 35 |
Issue number | 12 |
DOIs | |
State | Published - Jun 22 2021 |
All Science Journal Classification (ASJC) codes
- General Biochemistry, Genetics and Molecular Biology
Keywords
- T cell signaling
- optogenetics
- protein phase separation
- tyrosine kinases