Quantitative and temporal requirements revealed for Zap70 catalytic activity during T cell development

• Type of Material: Article
• Authors: Byron Au-Yeung, Emory University; Heather J. Melichar, University of California Berkeley; Jenny O. Ross, University of California Berkeley; Debra A. Cheng, University of California San Francisco; Julie Zikherman, University of California San Francisco; Kevan M. Shokat, University of California San Francisco; Ellen A. Robey, University of California Berkeley; Arthur Weiss, University of California San Francisco
• Language: English
• Date: 2014-07-01
• Publisher: Nature Research (part of Springer Nature)
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2014 Nature America, Inc. All rights reserved.
• Final Published Version (URL): http://dx.doi.org/10.1038/ni.2918
• Title of Journal or Parent Work: Nature Immunology
• ISSN: 1529-2908
• Volume: 15
• Issue: 7
• Start Page: 687
• End Page: 694
• Grant/Funding Information: We thank A. Roque for animal husbandry and C. Zhang for synthesis of 3-MB-PP1 and HXJ42. This work was supported by the Arthritis Foundation postdoctoral fellowship 5476 (to B.A.), the California Institute of Regenerative Medicine post-doctoral training grant T1-00007 (to H.J.M.), graduate student training grant TG2-01164 (to J.O.R.), the Rosalind Russell Medical Research Foundation Bechtel Award (to J.Z.), Arthritis National Research Foundation grant (to J.Z.), and NIH grants K08 AR059723 (to J.Z.), AI064227 (to E.R.), AI091580 (to A.W.) and RC2AR058947 (to A.W.).
• Keywords: TYROSINE KINASE; Immunology; REPERTOIRE; THYMOCYTE DEVELOPMENT; RECEPTOR; Science & Technology; DIFFERENTIATION; POSITIVE SELECTION; EXPRESSION; SYK; Life Sciences & Biomedicine; NEGATIVE SELECTION; ZAP-70
• Research Categories: Health Sciences, Pharmacology; Health Sciences, Immunology

Abstract

The catalytic activity of Zap70 is crucial for T cell antigen receptor (TCR) signaling, but the quantitative and temporal requirements for its function in thymocyte development are not known. Using a chemical-genetic system to selectively and reversibly inhibit Zap70 catalytic activity in a model of synchronized thymic selection, we showed that CD4 + CD8 + thymocytes integrate multiple, transient, Zap70-dependent signals over more than 36 h to reach a cumulative threshold for positive selection, whereas 1 h of signaling was sufficient for negative selection. Titration of Zap70 activity resulted in graded reductions in positive and negative selection but did not decrease the cumulative TCR signals integrated by positively selected OT-I cells, which revealed heterogeneity, even among CD4 + CD8 + thymocytes expressing identical TCRs undergoing positive selection.