Differential requirement for DOCK2 in migration of plasmacytoid dendritic cells versus myeloid dendritic cells.

The migratory properties of dendritic cells (DCs) are important for their functions. Although several chemokines and their receptors have been implicated in DC migration, the downstream signaling molecules are largely unknown. Here we show that DOCK2, a hematopoietic cell-specific CDM family protein, is indispensable for migration of plasmacytoid DCs (pDCs), but not myeloid DCs (mDCs).

T helper type 2 differentiation and intracellular trafficking of the interleukin 4 receptor-alpha subunit controlled by the Rac activator Dock2.

The lineage commitment of CD4+ T cells is coordinately regulated by signals through the T cell receptor and cytokine receptors, yet how these signals are integrated remains elusive. Here we find that mice lacking Dock2, a Rac activator in lymphocytes, developed allergic disease through a mechanism dependent on CD4+ T cells and the interleukin 4 receptor (IL-4R). Dock2-deficient CD4+ T cells showed impaired antigen-driven downregulation of IL-4Ralpha surface expression, resulting in sustained IL-4R signaling and excessive T helper type 2 responses.

DOCK2 is required in T cell precursors for development of Valpha14 NK T cells.

Mouse CD1d-restricted Valpha14 NKT cells are a unique subset of lymphocytes, which play important roles in immune regulation, tumor surveillance and host defense against pathogens. DOCK2, a mammalian homolog of Caenorhabditis elegans CED-5 and Drosophila melanogaster myoblast city, is critical for lymphocyte migration and regulates T cell responsiveness through immunological synapse formation, yet its role in Valpha14 NKT cells remains unknown. We found that DOCK2 deficiency causes marked reduction of Valpha14 NKT cells in the thymus, liver, and spleen.

Defective fetal liver erythropoiesis and T lymphopoiesis in mice lacking the phosphatidylserine receptor.

Clearance of apoptotic cells by macrophages is considered important for prevention of inflammatory responses leading to tissue damage. The phosphatidylserine receptor (PSR), which specifically binds to phosphatidylserine (PS) exposed on the surface of apoptotic cells, mediates uptake of apoptotic cells in vitro, yet the physiologic relevance of PSR remains unknown. This issue was addressed by generating PSR-deficient (PSR(-/-)) mice.

DOCK2 is essential for antigen-induced translocation of TCR and lipid rafts, but not PKC-theta and LFA-1, in T cells.

DOCK2 is a mammalian homolog of Caenorhabditis elegans CED-5 and Drosophila melanogaster Myoblast City which are known to regulate actin cytoskeleton. DOCK2 is critical for lymphocyte migration, yet the role of DOCK2 in TCR signaling remains unclear. We show here that DOCK2 is essential for TCR-mediated Rac activation and immunological synapse formation.

DOCK2 regulates Rac activation and cytoskeletal reorganization through interaction with ELMO1.

Although the migratory property of lymphocytes is critical for protective immunity, tissue infiltration of lymphocytes sometimes causes harmful immune responses. DOCK2 plays a critical role in lymphocyte migration by regulating actin cytoskeleton through Rac activation, yet the mechanism by which DOCK2 activates Rac remains unknown. We found that DOCK2 associates with engulfment and cell motility (ELMO1) through its Src-homology 3 (SH3) domain.