title: Identification of staphylococcal enterotoxin B domains involved in binding to cultured human kidney proximal tubular cells: imparting proliferation and death.
abstract: Studies suggest that staphylococcal enterotoxin B (SEB) is initially harbored in the kidney by binding to digalactosylceramide molecules in the proximal tubular cells. However, little is known in regard to the peptide motif within SEB that binds to these cells and imparts toxic effects. Herein, using human kidney proximal tubular cells (PTs) we have performed a systematic study on the binding of various peptides and peptide analogs of SEB and demonstrate a structure-functional relationship. Using [(125)I]labeled SEB peptides, we show a high affinity and displaceable binding of SEB 191-220 to human PT cells. Binding was mitigated by the use of antibody against SEB, by digalactosylceramide (the putative receptor), and by the use of endoglycoceramidase, which selectively removes the oligosaccharide backbones from glycosphingolipids. Our structure/ functional studies revealed that peptide 130-160 induces a concentration-dependent increase in programmed cell death/ apoptosis in human proximal tubular cells. Mechanistic studies further suggest that SEB/SEB peptide (130-160) impart apoptosis via the activation of neutral sphingomyelinase, which hydrolizes sphingomyelin to ceramide and phosphocholine. SEB 130-160 mediated apoptosis was mitigated by preincubation of cells with antibody against SEB and an SEB 130-160 antibody.
authors: Department of Pediatrics, Johns Hopkins University, Baltimore, Maryland 21205, USA. schatte2@jhmi.edu
authors: Subroto
authors: S
authors: Chatterjee
authors: Roger
authors: R
authors: Neill
authors: Jeffrey W
authors: JW
authors: Shupp
authors: Rasha
authors: R
authors: Hammamieh
authors: Boris
authors: B
authors: Ionin
authors: Marti
authors: M
authors: Jett
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis; D001665:Binding Sites; D049109:Cell Proliferation; D002478:Cells, Cultured; D004768:Enterotoxins / Q000737:chemistry* / Q000378:metabolism* / Q000494:pharmacology; D006026:Glycoside Hydrolases / Q000378:metabolism; D006028:Glycosphingolipids / Q000378:metabolism; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary
chemical_list: D004768:Enterotoxins; D006028:Glycosphingolipids; C002673:digalactosyl ceramide; C031818:enterotoxin B, staphylococcal; D006026:Glycoside Hydrolases; C050427:endoglycoceramidase