title: alpha-Hemolysin-induced dephosphorylation of EGF receptor of A431 cells is carried out by rPTPsigma.
abstract: Earlier we have shown that the epidermal growth factor receptor was unable to retain its phospho Tyr signal after the assembly of staphylococcal alpha-hemolysin (alpha-HL). However, the nature of the protein tyrosine phosphatase (PTPase) or its identity is not known. In this report, we demonstrate that the alpha-HL elevates the activity of receptor like protein tyrosine phosphatase sigma (rPTPsigma). The alpha-HL induced dephosphorylation is prominent only in intact A431 cells. The PTPase activity is not inhibited if the alpha-HL treatment precedes PTPase inhibitor treatments. The anti-EGFr immunoprecipitates have exhibited higher PTPase activity after alpha-HL treatment of A431 cells. Interestingly, PTPase activity of anti-EGFr immunoprecipitates from the A431 cells expressing the antisense message of rPTPsigma has not increased despite alpha-HL treatment, confirming the role of rPTPsigma in the dephosphorylation of EGFr. The studies presented here will be useful in understanding the process of signal modulation by the assembly of alpha-HL.
authors.affiliation: National Centre for Cell Science, Ganeshkhind Road, Pune 411007, India.
authors.forename: Ravi
authors.initials: R
authors.lastname: Vijayvargia
authors.forename: Surinder
authors.initials: S
authors.lastname: Kaur
authors.forename: M V
authors.initials: MV
authors.lastname: Krishnasastry
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000378:metabolism*; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D066246:ErbB Receptors / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D016211:Transforming Growth Factor alpha / Q000378:metabolism; D014638:Vanadates / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D006460:Hemolysin Proteins; D016211:Transforming Growth Factor alpha; C021091:staphylococcal alpha-toxin; D014638:Vanadates; D066246:ErbB Receptors; C516883:PTPRS protein, human; D017027:Protein Tyrosine Phosphatases; D054623:Receptor-Like Protein Tyrosine Phosphatases, Class 2; D002118:Calcium