鄧凱平博士學術講座08124
學術講座
講座題目：Anti-phagocytic activity of Haemophilus ducreyi LspA proteins
主 講 人：
主 持 人：
講座時間：2008年12月4日（星期四）下午3:30
講座地點：太阳集团1088vip學術報告廳（125室）
講座簡介：Haemophilus ducreyi is the etiologic agent of chancroid, a sexually transmitted genital ulcer disease. Two extremely large open reading frames in H. ducreyi genome encode LspA1 and LspA2 proteins that can be secreted and detected in culture supernatant fluid. The LspA proteins were shown to be associated with not only anti-phagocytic activity of this bacterium, but also a decrease of the level of Src family protein tyrosine kinases (PTKs), which are among the most proximal elements in phagocytic signaling pathway. In a further attempt to elucidate the anti-phagocytic mechanism, we found that LspA proteins were tyrosine phosphorylated after wild-type H. ducreyi was incubated with macrophages. This phosphorylation was not limited to cells of immune cell lineages. LspA proteins could also be phosphorylated after cell-free concentrated culture supernatant fluid was incubated with macrophages. Specific tyrosine residues in EPIYG and EPVYA motifs were identified by in silico methods and confirmed by site-directed mutagenesis. Fusion proteins containing these motifs were able to be phosphorylated by macrophages or purified Src PTK in vitro. The correlation between tyrosine phosphorylation of the LspA proteins and their anti-phagocytic activity is under investigation.
主講人簡介：鄧 凱