Tyrosine Phosphatase SHP-1 Is Involved in CD66-Mediated Phagocytosis of Opa(52)-Expressing Neisseria gonorrhoeae

Opa proteins of Neisseria gonorrhoeae bind to CD66 receptors on human phagocytes, thereby inducing efficient uptake of the bacteria in the absence of opsonins. The interaction of Opa proteins and CD66 receptors leads to activation of Src family tyrosine kinases, a process that is of critical importance for the efficient, CD66-mediated internalization. Here we show that during Opa-mediated stimulation of CD66 the activity of the host cell tyrosine phosphatase SHP-1 is strongly downregulated, concomitant with increases in the tyrosine phosphorylation of several cellular proteins. Since the SHP-1 tyrosine phosphorylation level itself is influenced by Opa-induced events, this phosphatase comprises an important regulatory checkpoint of the pathogen-triggered signaling cascade in human phagocytes.