An electrostatic selection mechanism controls sequential kinase signaling downstream of the T cell receptor
Neel H Shah,
Qi Wang,
Qingrong Yan,
Deepti Karandur,
Theresa A Kadlecek,
Ian R Fallahee,
William P Russ,
Rama Ranganathan,
Arthur Weiss,
John Kuriyan
Affiliations
Neel H Shah
Department of Molecular and Cell Biology, University of California, Berkeley, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, United States
Qi Wang
Department of Molecular and Cell Biology, University of California, Berkeley, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, United States
Qingrong Yan
Department of Molecular and Cell Biology, University of California, Berkeley, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, United States
Deepti Karandur
Department of Molecular and Cell Biology, University of California, Berkeley, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, United States
Theresa A Kadlecek
Rosalind Russell/Ephraim P Engleman Rheumatology Research Center, Department of Medicine, University of California, San Francisco, United States; Howard Hughes Medical Institute, University of California, San Francisco, United States
Ian R Fallahee
Department of Molecular and Cell Biology, University of California, Berkeley, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, United States
William P Russ
Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, United States
Rama Ranganathan
Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, United States; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, United States
Rosalind Russell/Ephraim P Engleman Rheumatology Research Center, Department of Medicine, University of California, San Francisco, United States; Howard Hughes Medical Institute, University of California, San Francisco, United States
Department of Molecular and Cell Biology, University of California, Berkeley, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, United States; Howard Hughes Medical Institute, University of California, Berkeley, United States; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, United States
The sequence of events that initiates T cell signaling is dictated by the specificities and order of activation of the tyrosine kinases that signal downstream of the T cell receptor. Using a platform that combines exhaustive point-mutagenesis of peptide substrates, bacterial surface-display, cell sorting, and deep sequencing, we have defined the specificities of the first two kinases in this pathway, Lck and ZAP-70, for the T cell receptor ζ chain and the scaffold proteins LAT and SLP-76. We find that ZAP-70 selects its substrates by utilizing an electrostatic mechanism that excludes substrates with positively-charged residues and favors LAT and SLP-76 phosphosites that are surrounded by negatively-charged residues. This mechanism prevents ZAP-70 from phosphorylating its own activation loop, thereby enforcing its strict dependence on Lck for activation. The sequence features in ZAP-70, LAT, and SLP-76 that underlie electrostatic selectivity likely contribute to the specific response of T cells to foreign antigens.
