SopB promotes phosphatidylinositol 3-phosphate formation on Salmonella vacuoles by recruiting Rab5 and Vps34.
Salmonella colonizes a vacuolar niche in host cells during infection. Maturation of the Salmonella-containing vacuole (SCV) involves the formation of phosphatidylinositol 3-phosphate (PI(3)P) on its outer leaflet. SopB, a bacterial virulence factor with phosphoinositide phosphatase activity, was proposed to generate PI(3)P by dephosphorylating PI(3,4)P2, PI(3,5)P2, and PI(3,4,5)P3. Here, we examine the mechanism of PI(3)P formation during Salmonella infection. SopB is required to form PI(3,4)P2/PI(3,4,5)P3 at invasion ruffles and PI(3)P on nascent SCVs. However, we uncouple these events experimentally and reveal that SopB does not dephosphorylate PI(3,4)P2/PI(3,4,5)P3 to produce PI(3)P. Instead, the phosphatase activity of SopB is required for Rab5 recruitment to the SCV. Vps34, a PI3-kinase that associates with active Rab5, is responsible for PI(3)P formation on SCVs. Therefore, SopB mediates PI(3)P production on the SCV indirectly through recruitment of Rab5 and its effector Vps34. These findings reveal a link between phosphoinositide phosphatase activity and the recruitment of Rab5 to phagosomes.
Mallo
Gustavo V
GV
Cell Biology Program, Hospital for Sick Children, Toronto, Ontario, Canada.
Espina
Marianela
M
Smith
Adam C
AC
Terebiznik
Mauricio R
MR
Alemán
Ainel
A
Finlay
B Brett
BB
Rameh
Lucia E
LE
Grinstein
Sergio
S
Brumell
John H
JH
D001426:Bacterial Proteins / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D022081:Cell Surface Extensions / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D012475:Salmonella / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D014617:Vacuoles / Q000187:drug effects / Q000201:enzymology*; D020696:rab5 GTP-Binding Proteins / Q000378:metabolism*
D001426:Bacterial Proteins; D019869:Phosphatidylinositol 3-Kinases; D018129:Phosphatidylinositol Phosphates; D000081082:Phosphoinositide-3 Kinase Inhibitors; D047428:Protein Kinase Inhibitors; D020696:rab5 GTP-Binding Proteins; C060974:phosphatidylinositol 3,4,5-triphosphate; C060980:phosphatidylinositol 3,4-diphosphate; C055525:phosphatidylinositol 3-phosphate; C489224:SopB protein, Salmonella