Adapter protein SH2-Bbeta stimulates actin-based motility of Listeria monocytogenes in a vasodilator-stimulated phosphoprotein (VASP)-dependent fashion.
SH2-Bbeta (Src homology 2 Bbeta) is an adapter protein that is required for maximal growth hormone-dependent actin reorganization in membrane ruffling and cell motility. Here we show that SH2-Bbeta is also required for maximal actin-based motility of Listeria monocytogenes. SH2-Bbeta localizes to Listeria-induced actin tails and increases the rate of bacterial propulsion in infected cells and in cell extracts. Furthermore, Listeria motility is decreased in mouse embryo fibroblasts from SH2-B(-/-) mice. Both recruitment of SH2-Bbeta to Listeria and SH2-Bbeta stimulation of actin-based propulsion require the vasodilator-stimulated phosphoprotein (VASP), which binds ActA at the surfaces of Listeria cells and enhances bacterial actin-based motility. SH2-Bbeta enhances actin-based movement of ActA-coated beads in a biomimetic actin-based motility assay, provided that VASP is present. In vitro binding assays show that SH2-Bbeta binds ActA but not VASP; however, binding to ActA is greater in the presence of VASP. Because VASP also plays an essential regulatory role in actin-based processes in eukaryotic cells, the present results provide mechanistic insight into the functions of both SH2-Bbeta and VASP in motility and also increase our understanding of the fundamental mechanism by which Listeria spreads.
Diakonova
Maria
M
Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA. mdiakon@utnet.utoledo.edu
Helfer
Emmanuele
E
Seveau
Stephanie
S
Swanson
Joel A
JA
Kocks
Christine
C
Rui
Liangyou
L
Carlier
Marie-France
MF
Carter-Su
Christin
C
D000199:Actins / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D019556:COS Cells; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D005347:Fibroblasts / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008089:Listeria monocytogenes / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008264:Macrophages / Q000382:microbiology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D009068:Movement / Q000502:physiology*; D009865:Oocytes / Q000382:microbiology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000254:growth & development / Q000382:microbiology; D000098662:Vasodilator-Stimulated Phosphoprotein
D000199:Actins; D048868:Adaptor Proteins, Signal Transducing; D001426:Bacterial Proteins; D015815:Cell Adhesion Molecules; D008565:Membrane Proteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; C115327:Sh2bpsm1 protein, mouse; D000098662:Vasodilator-Stimulated Phosphoprotein; C072980:actA protein, Listeria monocytogenes; D049452:Green Fluorescent Proteins