The granulocyte receptor carcinoembryonic antigen-related cell adhesion molecule 3 (CEACAM3) directly associates with Vav to promote phagocytosis of human pathogens

J Immunol. 2007 Mar 15;178(6):3797-805. doi: 10.4049/jimmunol.178.6.3797.

Abstract

The human granulocyte-specific receptor carcinoembryonic antigen-related cell adhesion molecule (CEACAM)3 is critically involved in the opsonin-independent recognition of several bacterial pathogens. CEACAM3-mediated phagocytosis depends on the integrity of an ITAM-like sequence within the cytoplasmic domain of CEACAM3 and is characterized by rapid stimulation of the GTPase Rac. By performing a functional screen with CEACAM3-expressing cells, we found that overexpression of a dominant-negative form of the guanine nucleotide exchange factor Vav, but not the dominant-negative versions SWAP70, Dock2, or ELMO1 interfered with CEACAM3-initiated phagocytosis. Moreover, small interfering RNA-mediated silencing of Vav reduced uptake and abrogated the stimulation of Rac in response to bacterial CEACAM3 engagement. In Vav1/Vav2-deficient cells, CEACAM3-mediated internalization was only observed after re-expression of Vav. Vav colocalized with CEACAM3 upon bacterial infection, coimmunoprecipitated in a complex with CEACAM3, and the Vav Src homology 2 domain directly associated with phosphorylated Tyr(230) of CEACAM3. In primary human granulocytes, TAT-mediated transduction of dominant-negative Vav, but not SWAP70, severely impaired the uptake of CEACAM3-binding bacteria. These data support the view that, different from canonical ITAM signaling, the CEACAM3 ITAM-like sequence short-wires bacterial recognition and Rac stimulation via a direct association with Vav to promote rapid phagocytosis and elimination of CEACAM-binding human pathogens.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / immunology
  • Carcinoembryonic Antigen / immunology*
  • Cell Line
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / immunology
  • GTPase-Activating Proteins
  • Gene Silencing
  • Granulocytes / cytology
  • Granulocytes / immunology*
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / immunology
  • Minor Histocompatibility Antigens
  • Neisseria gonorrhoeae / genetics
  • Neisseria gonorrhoeae / immunology*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / immunology
  • Phagocytosis / genetics
  • Phagocytosis / immunology*
  • Proto-Oncogene Proteins c-vav / deficiency
  • Proto-Oncogene Proteins c-vav / immunology*
  • RNA, Small Interfering / genetics
  • Signal Transduction / genetics
  • Signal Transduction / immunology
  • src Homology Domains / genetics
  • src Homology Domains / immunology

Substances

  • Adaptor Proteins, Signal Transducing
  • CEACAM3 protein, human
  • Carcinoembryonic Antigen
  • DNA-Binding Proteins
  • DOCK2 protein, human
  • ELMO1 protein, human
  • GTPase-Activating Proteins
  • Guanine Nucleotide Exchange Factors
  • Minor Histocompatibility Antigens
  • Nuclear Proteins
  • Proto-Oncogene Proteins c-vav
  • RNA, Small Interfering
  • SWAP70 protein, human
  • VAV1 protein, human
  • VAV2 protein, human