Cortactin and Crk cooperate to trigger actin polymerization during Shigella invasion of epithelial cells.
Shigella, the causative agent of bacillary dysentery, invades epithelial cells in a process involving Src tyrosine kinase signaling. Cortactin, a ubiquitous actin-binding protein present in structures of dynamic actin assembly, is the major protein tyrosine phosphorylated during Shigella invasion. Here, we report that RNA interference silencing of cortactin expression, as does Src inhibition in cells expressing kinase-inactive Src, interferes with actin polymerization required for the formation of cellular extensions engulfing the bacteria. Shigella invasion induced the recruitment of cortactin at plasma membranes in a tyrosine phosphorylation-dependent manner. Overexpression of wild-type forms of cortactin or the adaptor protein Crk favored Shigella uptake, and Arp2/3 binding-deficient cortactin derivatives or an Src homology 2 domain Crk mutant interfered with bacterial-induced actin foci formation. Crk was shown to directly interact with tyrosine-phosphorylated cortactin and to condition cortactin-dependent actin polymerization required for Shigella uptake. These results point at a major role for a Crk-cortactin complex in actin polymerization downstream of tyrosine kinase signaling.
Bougnères
Laurence
L
Unité de Pathogénie Microbienne Moléculaire, INSERM U389, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France. gtranvan@pasteur.fr
Girardin
Stéphane E
SE
Weed
Scott A
SA
Karginov
Andrei V
AV
Olivo-Marin
Jean-Christophe
JC
Parsons
J Thomas
JT
Sansonetti
Philippe J
PJ
Van Nhieu
Guy Tran
GT
D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism / Q000382:microbiology; D022081:Cell Surface Extensions / Q000382:microbiology; D051356:Cortactin; D004705:Endocytosis; D004847:Epithelial Cells / Q000382:microbiology* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D011485:Protein Binding; D050737:Proto-Oncogene Proteins c-crk; D034741:RNA, Small Interfering / Q000494:pharmacology; D012760:Shigella / Q000502:physiology*
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; C485285:CRK protein, human; C495868:CTTN protein, human; D051356:Cortactin; D008840:Microfilament Proteins; D050737:Proto-Oncogene Proteins c-crk; D034741:RNA, Small Interfering