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The invasion protein InIB from Listeria monocytogenes activates PLC-gamma1 downstream from PI 3-kinase.

Authors :
Bierne H
Dramsi S
Gratacap MP
Randriamampita C
Carpenter G
Payrastre B
Cossart P
Source :
Cellular microbiology [Cell Microbiol] 2000 Dec; Vol. 2 (6), pp. 465-76.
Publication Year :
2000

Abstract

Entry of the bacterial pathogen Listeria monocytogenes into non-phagocytic mammalian cells is mainly mediated by the InlB protein. Here we show that in the human epithelial cell line HEp-2, the invasion protein InlB activates sequentially a p85beta-p110 class I(A) PI 3-kinase and the phospholipase C-gamma1 (PLC-gamma1) without detectable tyrosine phosphorylation of PLC-gamma1. Purified InlB stimulates association of PLC-gamma1 with one or more tyrosine-phosphorylated proteins, followed by a transient increase in intracellular inositol 1,4,5-trisphosphate (IP3) levels and a release of intracellular Ca2+ in a PI 3-kinase-dependent manner. Infection of HEp-2 cells with wild-type L. monocytogenes bacteria also induces association of PLC-gamma1 with phosphotyrosyl proteins. This interaction is undetectable upon infection with a deltainlB mutant revealing an InlB specific signal. Interestingly, pharmacological or genetic inactivation of PLC-gamma1 does not significantly affect InlB-mediated bacterial uptake, suggesting that InlB-mediated PLC-gamma1 activation and calcium mobilization are involved in post-internalization steps.

Details

Language :
English
ISSN :
1462-5814
Volume :
2
Issue :
6
Database :
MEDLINE
Journal :
Cellular microbiology
Publication Type :
Academic Journal
Accession number :
11207601
Full Text :
https://doi.org/10.1046/j.1462-5822.2000.00069.x