A DOCK8-WIP-WASp complex links T cell receptors to the actin cytoskeleton
Erin Janssen, … , Francis W. Luscinskas, Raif S. Geha
Erin Janssen, … , Francis W. Luscinskas, Raif S. Geha
Published September 6, 2016
Citation Information: J Clin Invest. 2016;126(10):3837-3851. https://doi.org/10.1172/JCI85774.
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Research Article Immunology

A DOCK8-WIP-WASp complex links T cell receptors to the actin cytoskeleton

Abstract

Wiskott-Aldrich syndrome (WAS) is associated with mutations in the WAS protein (WASp), which plays a critical role in the initiation of T cell receptor–driven (TCR-driven) actin polymerization. The clinical phenotype of WAS includes susceptibility to infection, allergy, autoimmunity, and malignancy and overlaps with the symptoms of dedicator of cytokinesis 8 (DOCK8) deficiency, suggesting that the 2 syndromes share common pathogenic mechanisms. Here, we demonstrated that the WASp-interacting protein (WIP) bridges DOCK8 to WASp and actin in T cells. We determined that the guanine nucleotide exchange factor activity of DOCK8 is essential for the integrity of the subcortical actin cytoskeleton as well as for TCR-driven WASp activation, F-actin assembly, immune synapse formation, actin foci formation, mechanotransduction, T cell transendothelial migration, and homing to lymph nodes, all of which also depend on WASp. These results indicate that DOCK8 and WASp are in the same signaling pathway that links TCRs to the actin cytoskeleton in TCR-driven actin assembly. Further, they provide an explanation for similarities in the clinical phenotypes of WAS and DOCK8 deficiency.

Authors

Erin Janssen, Mira Tohme, Mona Hedayat, Marion Leick, Sudha Kumari, Narayanaswamy Ramesh, Michel J. Massaad, Sumana Ullas, Veronica Azcutia, Christopher C. Goodnow, Katrina L. Randall, Qi Qiao, Hao Wu, Waleed Al-Herz, Dianne Cox, John Hartwig, Darrell J. Irvine, Francis W. Luscinskas, Raif S. Geha

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Figure 1

DOCK8 interacts constitutively and colocalizes with WASp and WIP in T cells.

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DOCK8 interacts constitutively and colocalizes with WASp and WIP in T ce...
(A and B) Co-IP of WIP and WASp with DOCK8, but not MALT1, in human peripheral blood T cells (A) and mouse splenic T cells (B). Aliquots from the lysates used for IP were probed with DOCK8, WASp, WIP, and MALT1 to ensure equal loading. (C) Lack of a detectable effect of TCR ligation with anti-CD3 mAb on the association of DOCK8 with WIP and WASp in human blood T cells. Lysates were probed with a phospho-specific ERK1/ERK2 (p-ERK1/2) Ab to verify TCR signaling and with GAPDH as a loading control. IP with an IgG isotype Ab was used as a negative control. (D) Co-IP of WIP and WASp with DOCK8, but not MALT1, in the human DND41 T cell line. (E) Colocalization of WIP and WASp with DOCK8. Representative DIC images (left), confocal immunofluorescence microscopic images (middle), and merged images (right) of DND41 T cells permeabilized and stained with Abs against DOCK8, WIP, and WASp, followed by fluorochrome-labeled secondary Abs. Original magnification, ×63. Scale bars: 2 μm. Data in A–D represent 3 independent experiments each. Images in E are representative of 50 cells that were examined in 2 independent experiments.