SAP facilitates recruitment and activation of LCK at NTB-A receptors during restimulation-induced cell death

Gil Katz, Scott M. Krummey, Sasha E. Larsen, Jeffrey R. Stinson, Andrew L. Snow

Research output: Contribution to journalArticlepeer-review

Abstract

Upon TCR restimulation, activated, cycling T cells can undergo a self-regulatory form of apoptosis known as restimulation-induced cell death (RICD). We previously demonstrated that RICD is impaired in T cells from patients with X-linked lymphoproliferative disease, which lack SLAM-associated protein (SAP) expression. Both SAP and the specific SLAM receptor NK, T, and B cell Ag (NTB-A) are required for RICD, but the mechanism by which these molecules promote a strong, proapoptotic signal through the TCR remains unclear. In this article, we show that the Src-family kinase LCK, but not FYN, associates with NTB-A in activated human T cells. This association increased after TCR restimulation in a SAP-dependent manner, requiring both immunoreceptor tyrosine-based switch motifs in the NTB-A cytoplasmic tail. Both NTB-A-associated LCK phosphorylation and kinase activity were enhanced in restimulated T cells, amplifying proximal TCR signaling. In contrast, TCR-induced LCK association with NTB-A, as well as phosphorylation and kinase activity, was reduced in T cells from patients with X-linked lymphoproliferative disease or normal T cells transfected with SAP-specific small interfering RNA, consistent with RICD resistance. Collectively, our data reveal how SAP nucleates a previously unknown signaling complex involving NTB-A and LCK to potentiate RICD of activated human T cells. The Journal of Immunology, 2014, 192: 4202-4209.

Original languageEnglish (US)
Pages (from-to)4202-4209
Number of pages8
JournalJournal of Immunology
Volume192
Issue number9
DOIs
StatePublished - May 1 2014
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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