α-Hemolysin-induced dephosphorylation of EGF receptor of A431 cells is carried out by rPTPσ

• Published in: Biochemical and biophysical research communications 2004-12, Vol.325 (1), p.344-352
• Main Authors: Vijayvargia, Ravi, Kaur, Surinder, Krishnasastry, M.V.
• Format: Article
• Language: English
• Subjects: Dephosphorylation; Epidermal growth factor receptor; PTPase activity; Receptor protein tyrosine phosphatase sigma; α-Hemolysin
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2004.10.038

Earlier we have shown that the epidermal growth factor receptor was unable to retain its phospho Tyr signal after the assembly of staphylococcal α-hemolysin (α-HL). However, the nature of the protein tyrosine phosphatase (PTPase) or its identity is not known. In this report, we demonstrate that the α-HL elevates the activity of receptor like protein tyrosine phosphatase σ (rPTPσ). The α-HL induced dephosphorylation is prominent only in intact A431 cells. The PTPase activity is not inhibited if the α-HL treatment precedes PTPase inhibitor treatments. The anti-EGFr immunoprecipitates have exhibited higher PTPase activity after α-HL treatment of A431 cells. Interestingly, PTPase activity of anti-EGFr immunoprecipitates from the A431 cells expressing the antisense message of rPTPσ has not increased despite α-HL treatment, confirming the role of rPTPσ in the dephosphorylation of EGFr. The studies presented here will be useful in understanding the process of signal modulation by the assembly of α-HL.