Immunoreceptor tyrosine‐based activation motif phosphorylation during engulfment of Neisseria gonorrhoeae by the neutrophil‐restricted CEACAM3 (CD66d) receptor

• Published in: Molecular microbiology Vol. 49; no. 3; pp. 623 - 637
• Main Authors: McCaw, Shannon E., Schneider, Jutta, Liao, Edward H., Zimmermann, Wolfgang, Gray‐Owen, Scott D.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-08-2003
• Subjects: Actin Cytoskeleton - ultrastructure; Adhesins, Bacterial - genetics; Adhesins, Bacterial - metabolism; Amino Acid Motifs; Amino Acid Sequence; Antigens, Bacterial; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Carcinoembryonic Antigen - chemistry; Carcinoembryonic Antigen - genetics; Carcinoembryonic Antigen - metabolism; cytochalasin D; Cytoskeleton - metabolism; Cytoskeleton - ultrastructure; HeLa Cells - metabolism; HeLa Cells - microbiology; Humans; immunoreceptor tyrosine-based activation motif; Molecular Sequence Data; Neisseria gonorrhoeae; Neisseria gonorrhoeae - genetics; Neisseria gonorrhoeae - metabolism; Neutrophils - metabolism; Neutrophils - microbiology; Neutrophils - ultrastructure; Opa protein; Phosphorylation; Protein Processing, Post-Translational; Proteoglycans - genetics; Proteoglycans - metabolism; Receptors, Cell Surface - genetics; Receptors, Cell Surface - metabolism; Recombinant Fusion Proteins - metabolism; src-Family Kinases - metabolism; Transfection
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1046/j.1365-2958.2003.03591.x

Summary
Gonorrhea is characterized by a purulent urethral or cervical discharge consisting primarily of neutrophils associated with Neisseria gonorrhoeae. These interactions are facilitated by gonococcal colony opacity‐associated (Opa) protein binding to host cellular CEACAM receptors. Of these, CEACAM3 is restricted to neutrophils and contains an immunoreceptor tyrosine‐based activation motif (ITAM) reminiscent of that found within certain phagocytic Fc receptors. CEACAM3 was tyrosine phosphorylated by a Src family kinase‐dependent process upon infection by gonococci expressing CEACAM‐specific Opa proteins. This phosphorylation was necessary for efficient bacterial uptake; however, a less efficient uptake process became evident when kinase inhibitors or mutagenesis of the ITAM were used to prevent phosphorylation. Ligated CEACAM3 was recruited to a cytoskeleton‐containing fraction, intense foci of polymerized actin were evident where bacteria attached to HeLa‐CEACAM3, and disruption of polymerized actin by cytochalasin D blocked all bacterial uptake by these cells. These data support a model whereby CEACAM3 can mediate the Opa‐dependent uptake of N. gonorrhoeae via either an efficient, ITAM phosphorylation‐dependent process that resembles phagocytosis or a less efficient, tyrosine phosphorylation‐independent mechanism.