alpha-Hemolysin-induced dephosphorylation of EGF receptor of A431 cells is carried out by rPTPsigma.
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.
Vijayvargia
Ravi
R
National Centre for Cell Science, Ganeshkhind Road, Pune 411007, India.
Kaur
Surinder
S
Krishnasastry
M V
MV
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
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