Download MendeleyDynamic regulation of CD28 conformation and signaling by charged lipids and ions.
Yang, W., Pan, W., Chen, S., Trendel, N., Jiang, S., Xiao, F., Xue, M., Wu, W., Peng, Z., Li, X., Ji, H., Liu, X., Jiang, H., Wang, H., Shen, H., Dushek, O., Li, H., Xu, C.(2017) Nat Struct Mol Biol 24: 1081-1092
- PubMed: 29058713
- DOI: https://doi.org/10.1038/nsmb.3489
- Primary Citation of Related Structures:
2NAE - PubMed Abstract:
CD28 provides an essential costimulatory signal for T cell activation, and its function is critical in antitumor immunity. However, the molecular mechanism of CD28 transmembrane signaling remains elusive. Here we show that the conformation and signaling of CD28 are regulated by two counteractive charged factors, acidic phospholipids and Ca 2+ ions. NMR spectroscopy analyses showed that acidic phospholipids can sequester CD28 signaling motifs within the membrane, thereby limiting CD28 basal signaling. T cell receptor (TCR) activation induced an increase in the local Ca 2+ concentration around CD28, and Ca 2+ directly disrupted CD28-lipid interaction, leading to opening and signaling of CD28. We observed that the TCR, Ca 2+ , and CD28 together form a dual-positive-feedback circuit that substantially amplifies T cell signaling and thus increases antigen sensitivity. This work unravels a new regulatory mechanism for CD28 signaling and thus contributes to the understanding of the dependence of costimulation signaling on TCR signaling and the high sensitivity of T cells.
Organizational Affiliation:
State Key Laboratory of Molecular Biology, National Center for Protein Science Shanghai, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China.
