title: Binding of erythroagglutinating phytohemagglutinin lectin from Phaseolus vulgaris to the epidermal growth factor receptor inhibits receptor function in the human glioma cell line, U373 MG.
abstract: Little is known about the role of the N-linked oligosaccharides in the function of the epidermal growth factor (EGF) receptor (EGF-R). In a human glioma cell line, U373 MG, EGF-Rs contain the bisecting N-linked oligosaccharide sequence recognized by erythroagglutinating phytohemagglutinin lectin from Phaseolus vulgaris (E-PHA). Incubation of E-PHA with cultured U373 MG cells results in inhibition of EGF binding to its receptor and consequently inhibition of EGF-induced autophosphorylation of the receptor. Consistent with the inhibitory effects on the EGF-R, phenotypic events that depend on EGF-R signaling, such as cell spreading and proliferation, were also found to be modified. The effect of this lectin seems to be specific because leukoagglutinating phytohemagglutinin lectin from P. vulgaris (L-PHA), an isolectin of E-PHA, had no effect on EGF-R activity or the biological functions of these cells even though L-PHA was able to bind to the EGF-R. These findings suggest the presence of an important bisecting N-linked oligosaccharide structure in close proximity to the EGF binding site on the receptor. Furthermore, these results suggest the possibility that E-PHA lectin binding may provide an additional approach to blocking EGF-dependent glioma cell growth.
authors.affiliation: Chicago Institute of Neurosurgery and Neuroresearch, Illinois, USA.
authors.forename: A
authors.initials: A
authors.lastname: Rebbaa
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
authors.forename: J R
authors.initials: JR
authors.lastname: Moskal
authors.forename: E G
authors.initials: EG
authors.lastname: Bremer
mesh_terms: D002455:Cell Division / Q000187:drug effects; D066246:ErbB Receptors / Q000819:agonists* / Q000502:physiology*; D005910:Glioma; D006801:Humans; D007536:Isomerism; D009844:Oligosaccharides / Q000032:analysis; D010766:Phosphorylation; D010835:Phytohemagglutinins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000502:physiology
chemical_list: D009844:Oligosaccharides; D010835:Phytohemagglutinins; C067494:erythroagglutinating phytohemagglutinin; C100156:leukoagglutinins, plants; D066246:ErbB Receptors