An invasion-associated Salmonella protein modulates the actin-bundling activity of plastin.
The entry of Salmonella typhimurium into nonphagocytic cells requires a panel of bacterial effector proteins that are delivered to the host cell via a type III secretion system. These proteins modulate host-cell signal-transduction pathways and the actin cytoskeleton to induce membrane ruffling and bacterial internalization. One of these bacterial effectors, termed SipA, is an actin-binding protein that is required for efficient Salmonella entry into host cells. We report here that SipA forms a complex with T-plastin on bacterial infection. Formation of such a complex, which requires the presence of F-actin, results in a marked increase in the actin-bundling activity of T-plastin. We also report that T-plastin is recruited to S. typhimurium-induced membrane ruffles by a CDC42-dependent signaling process and is required for bacterial entry. We propose that modulation of the actin-bundling activity of T-plastin by SipA results in the stabilization of the actin filaments at the point of bacterial-host cell contact, which leads to more efficient Salmonella internalization.
Zhou
D
D
Section of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, CT 06536, USA.
Mooseker
M S
MS
Galán
J E
JE
D000199:Actins / Q000378:metabolism* / Q000648:ultrastructure; D001426:Bacterial Proteins / Q000378:metabolism; D003599:Cytoskeleton / Q000502:physiology / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins / Q000378:metabolism*; D008854:Microscopy, Electron; D010586:Phagocytes / Q000382:microbiology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012486:Salmonella typhimurium / Q000472:pathogenicity* / Q000502:physiology*; D015398:Signal Transduction; D014162:Transfection
D000199:Actins; D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011993:Recombinant Fusion Proteins; C118287:SipA protein, Salmonella; C103987:SopE protein, Salmonella; C026742:plastin