Studying the dynamics of SLP-76, Nck, and Vav1 multimolecular complex formation in live human cells with triple-color FRET

Maor H. Pauker, Nirit Hassan, Elad Noy, Barak Reicher, Mira Barda-Saad

Research output: Contribution to journalArticlepeer-review

Abstract

Protein-protein interactions regulate and control many cellular functions. A multimolecular complex consisting of the adaptor proteins SLP-76 (Src homology 2 domain - containing leukocyte protein of 76 kD), Nck, and the guanine nucleotide exchange factor Vav1 is recruited to the T cell side of the interface with an antigen-presenting cell during initial T cell activation. This complex is crucial for regulation of the actin machinery, antigen recognition, and signaling in T cells. We studied the interactions between these proteins as well as the dynamics of their recruitment into a complex that governs cytoskeletal reorganization. We developed a triple-color Förster resonance energy transfer (3FRET) system to observe the dynamics of the formation of this trimolecular signaling complex in live human T cells and to follow the three molecular interactions in parallel. Using the 3FRET system, we demonstrated that dimers of Nck and Vav1 were constitutively formed independently of both T cell activation and the association between SLP-76 and Nck. After T cell receptor stimulation, SLP-76 was phosphorylated, which enabled the binding of Nck. A point mutation in the proline-rich site of Vav1, which abolishes its binding to Nck, impaired actin rearrangement, suggesting that Nck-Vav1 dimers play a critical role in regulation of the actin machinery. We suggest that these findings revise the accepted model of the formation of a complex of SLP-76, Nck, and Vav1 and demonstrate the use of 3FRET as a tool to study signal transduction in live cells.

Original languageEnglish
Article numberrs3
JournalScience Signaling
Volume5
Issue number221
DOIs
StatePublished - 24 Apr 2012

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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