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The EMBO Journal
(2000) 19, 1458–1466, doi:10.1093/emboj/19.7.1458
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| gC1q-R/p32, a C1q-binding protein, is a receptor for the InlB invasion protein of Listeria monocytogenes |
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Laurence Braun1, Berhane Ghebrehiwet2 and Pascale Cossart1
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1 Unité des Interactions Bactéries–Cellules, Institut Pasteur, 28 rue du Docteur Roux, 75724 Paris cedex 15, France
2 Department of Medicine, Health Sciences Center, T16-040, State University of New York, Stony Brook, NY 11794-8161, USA
To whom correspondence should be addressed
Pascale Cossart, pcossart@pasteur.fr
Received 23 December 1999; Revised 4 February 2000; Accepted 4 February 2000.
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| Abstract |
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| InlB is a Listeria monocytogenes protein that promotes entry of the bacterium into mammalian cells by stimulating tyrosine phosphorylation of the adaptor proteins Gab1, Cbl and Shc, and activation of phosphatidylinositol (PI) 3-kinase. Using affinity chromatography and enzyme-linked immunosorbent assay, we demonstrate a direct interaction between InlB and the mammalian protein gC1q-R, the receptor of the globular part of the complement component C1q. Soluble C1q or anti-gC1q-R antibodies impair InlB-mediated entry. Transient transfection of GPC16 cells, which are non-permissive to InlB-mediated entry, with a plasmid-expressing human gC1q-R promotes entry of InlB-coated beads. Furthermore, several experiments indicate that membrane recruitment and activation of PI 3-kinase involve an InlB–gC1q-R interaction and that gC1q-R associates with Gab1 upon stimulation of Vero cells with InlB. Thus, gC1q-R constitutes a cellular receptor involved in InlB-mediated activation of PI 3-kinase and tyrosine phosphorylation of the adaptor protein Gab1. After E-cadherin, the receptor for internalin, gC1q-R is the second identified mammalian receptor promoting entry of L.monocytogenes into mammalian cells. |
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| Keywords: gC1q-R, InlB, invasion, Listeria, signaling |
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