Shigella flexneri utilize the spectrin cytoskeleton during invasion and comet tail generation
1 Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada
2 Department of Biological Sciences, Shrum Science Centre, Simon Fraser University, Room B8276, Burnaby, B.C. V5A 1S6, Canada
BMC Microbiology 2012, 12:36 doi:10.1186/1471-2180-12-36Published: 16 March 2012
The spectrin cytoskeleton is emerging as an important host cell target of enteric bacterial pathogens. Recent studies have identified a crucial role for spectrin and its associated proteins during key pathogenic processes of Listeria monocytogenes and Salmonella Typhimurium infections. Here we investigate the involvement of spectrin cytoskeletal components during the pathogenesis of the invasive pathogen Shigella flexneri.
Immunofluorescent microscopy reveals that protein 4.1 (p4.1), but not adducin or spectrin, is robustly recruited to sites of S. flexneri membrane ruffling during epithelial cell invasion. Through siRNA-mediated knockdowns, we identify an important role for spectrin and the associated proteins adducin and p4.1 during S. flexneri invasion. Following internalization, all three proteins are recruited to the internalized bacteria, however upon generation of actin-rich comet tails, we observed spectrin recruitment to those structures in the absence of adducin or p4.1.
These findings highlight the importance of the spectrin cytoskeletal network during S. flexneri pathogenesis and further demonstrate that pathogenic events that were once thought to exclusively recruit the actin cytoskeletal system require additional cytoskeletal networks.