Open AccessCritical Role for the Host GTPase-Activating Protein ARAP2 in InlB-Mediated Entry of Listeria monocytogenes
Author(s) -
Balramakrishna Gavicherla,
Lisa Ritchey,
Antonella Gianfelice,
Andrey A. Kolokoltsov,
Robert A. Davey,
Keith Ireton
Publication year - 2010
Publication title -
infection and immunity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.508
H-Index - 220
eISSN - 1070-6313
pISSN - 0019-9567
DOI - 10.1128/iai.00802-10
Subject(s) - rhoa , internalization , biology , gtpase , microbiology and biotechnology , listeria monocytogenes , rna interference , actin cytoskeleton , small interfering rna , binding domain , gtpase activating protein , rac1 , cytoskeleton , signal transduction , receptor , rna , binding site , g protein , genetics , cell , gene , bacteria
The bacterial pathogenListeria monocytogenes causes food-borne illnesses culminating in gastroenteritis, meningitis, or abortion.Listeria induces its internalization into some mammalian cells through binding of the bacterial surface protein InlB to the host receptor tyrosine kinase Met. Interaction of InlB with the Met receptor elicits host downstream signaling pathways that promote F-actin cytoskeletal changes responsible for pathogen engulfment. Here we show that the mammalian signaling protein ARAP2 plays a critical role in cytoskeletal remodeling and internalization ofListeria . Depletion of ARAP2 through RNA interference (RNAi) caused a marked inhibition of InlB-mediated F-actin rearrangements and bacterial entry. ARAP2 contains multiple functional domains, including a GTPase-activating protein (GAP) domain that antagonizes the GTPase Arf6 and a domain capable of binding the GTPase RhoA. Genetic data indicated roles for both the Arf GAP and RhoA binding domains inListeria entry. Experiments involving Arf6 RNAi or a constitutively activated allele of Arf6 demonstrated that one of the ways in which ARAP2 promotes bacterial uptake is by restraining the activity of Arf6. Conversely, Rho activity was dispensable forListeria internalization, suggesting that the RhoA binding domain in ARAP2 acts by engaging a host ligand other than Rho proteins. Collectively, our findings indicate that ARAP2 promotes InlB-mediated entry ofListeria , in part, by antagonizing the host GTPase Arf6.