TY - JOUR
T1 - Phosphatidylinositol 4,5-bisphosphatedependent oligomerization of the Pseudomonas aeruginosa cytotoxin ExoU
AU - Zhang, Angelica
AU - Veesenmeyer, Jeffrey L.
AU - Hauser, Alan R.
N1 - Funding Information:
This work was supported by National Institutes of Health grants K24 AI04831 (to A.R.H.), R01 AI053674 (to A.R.H.), R01 AI118257 (to A.R.H.), F30HL107092 (to A.Z.), and T32GM008152 (to A.Z.). The Keck Biophysics Facility is supported in part by NCI CCSG P30CA060553, awarded to the Robert H. Lurie Comprehensive Cancer Center.
PY - 2018/1/1
Y1 - 2018/1/1
N2 - The Pseudomonas aeruginosa type III secretion system delivers effector proteins directly into target cells, allowing the bacterium to modulate host cell functions. ExoU is the most cytotoxic of the known effector proteins and has been associated with more severe infections in humans. ExoU is a patatin-like A2 phospholipase requiring the cellular host factors phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and ubiquitin for its activation in vitro. We demonstrated that PI(4,5)P2 also induces the oligomerization of ExoU and that this PI(4,5)P2-mediated oligomerization does not require ubiquitin. Single amino acid substitutions in the C-terminal membrane localization domain of ExoU reduced both its activity and its ability to form higher-order complexes in transfected cells and in vitro. Combining inactive truncated ExoU proteins partially restored phospholipase activity and cytotoxicity, indicating that ExoU oligomerization may have functional significance. Our results indicate that PI(4,5)P2 induces the oligomerization of ExoU, which may be a mechanism by which this coactivator enhances the phospholipase activity of ExoU.
AB - The Pseudomonas aeruginosa type III secretion system delivers effector proteins directly into target cells, allowing the bacterium to modulate host cell functions. ExoU is the most cytotoxic of the known effector proteins and has been associated with more severe infections in humans. ExoU is a patatin-like A2 phospholipase requiring the cellular host factors phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and ubiquitin for its activation in vitro. We demonstrated that PI(4,5)P2 also induces the oligomerization of ExoU and that this PI(4,5)P2-mediated oligomerization does not require ubiquitin. Single amino acid substitutions in the C-terminal membrane localization domain of ExoU reduced both its activity and its ability to form higher-order complexes in transfected cells and in vitro. Combining inactive truncated ExoU proteins partially restored phospholipase activity and cytotoxicity, indicating that ExoU oligomerization may have functional significance. Our results indicate that PI(4,5)P2 induces the oligomerization of ExoU, which may be a mechanism by which this coactivator enhances the phospholipase activity of ExoU.
KW - ExoU
KW - Oligomerization
KW - Pseudomonas aeruginosa
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U2 - 10.1128/IAI.00402-17
DO - 10.1128/IAI.00402-17
M3 - Article
C2 - 28993456
AN - SCOPUS:85039561661
VL - 86
JO - Infection and Immunity
JF - Infection and Immunity
SN - 0019-9567
IS - 1
M1 - e00402-17
ER -