title: The enteropathogenic Escherichia coli effector protein EspF decreases sodium hydrogen exchanger 3 activity.
abstract: Enteropathogenic Escherichia coli (EPEC) have been previously shown to alter sodium hydrogen exchanger 3 (NHE3) activity in human intestinal epithelial cells. To further characterize these observations, PS120 fibroblasts transfected with NHE3 were studied. EPEC E2348/69 infection decreased NHE3 activity in PS120 fibroblasts. The effect on NHE3 was enhanced when PS120 cells were co-transfected with the scaffolding/regulatory proteins NHERF1 or NHERF2 or EBP50 and E3KARP respectively. The decrease in NHE3 activity was dependent on an intact type III secretion system, although intimate attachment mediated by translocated intimin receptor was not required. Despite its ability to bind to NHERF proteins, the EPEC effector Map had no impact on the regulation of NHE activity. Instead, EspF was found to be responsible for decreased NHE3 activity. However, neither EspF-induced apoptosis nor the interaction of EspF with sorting nexin-9, an endocytic protein, were involved.
authors.affiliation: Section of Digestive Disease and Nutrition, Department Of Medicine, University of Illinois at Chicago, Jesse Brown VA Medical Center, Chicago, IL 60612, USA.
authors.forename: Kim
authors.initials: K
authors.lastname: Hodges
authors.forename: Neal M
authors.initials: NM
authors.lastname: Alto
authors.forename: K
authors.initials: K
authors.lastname: Ramaswamy
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Dudeja
authors.forename: Gail
authors.initials: G
authors.lastname: Hecht
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism*; D015536:Down-Regulation; D054308:Enteropathogenic Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D005347:Fibroblasts / Q000382:microbiology; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology*; D047908:Intracellular Signaling Peptides and Proteins; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C489109:EspFU protein, E coli; D047908:Intracellular Signaling Peptides and Proteins; C000613385:SLC9A3 protein, human; C400533:SNX9 protein, human; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; D058305:Sorting Nexins; D033921:Vesicular Transport Proteins