TY - JOUR
T1 - The roles of protein phosphorylation/dephosphorylation in tumor necrosis factor antitumor effects
AU - Wang, Xin Yuan
AU - Kafka, Michael
AU - Dvilansky, Alexander
AU - Nathan, Ilana
PY - 1996/1/1
Y1 - 1996/1/1
N2 - The roles of protein phosphorylation and dephosphorylation in the tumor necrosis factor (TNF) cytotoxic and antiproliferative effects on L-929- transformed fibroblasts were explored. Genistein and erbstatin, specific inhibitors of tyrosine kinase, had antiproliferative but not cytotoxic effects on the cells by themselves and synergistically enhanced the cytotoxic and antiproliferative effects of TNF-α. Immunoblot analysis with a monoclonal antiphosphotyrosine antibody revealed that TNF, administered for 5-180 min, induced tyrosine dephosphorylation of two pairs of membranal proteins, 34-36 kDa and 50-52 kDa, and potentiated tyrosine phosphorylation of a 115-kDa protein in both the cytosolic and membranal fractions of the cells. A very brief exposure (30 sec) to TNF induced rapid phosphorylation of several proteins, whereas genistein, but not inhibitors of other protein kinases, enhanced this effect of TNF. The results suggest that TNF activity could be potentiated by the inhibition of tyrosine phosphorylation and point to specific proteins that are dephosphorylated on tyrosine in response to TNF.
AB - The roles of protein phosphorylation and dephosphorylation in the tumor necrosis factor (TNF) cytotoxic and antiproliferative effects on L-929- transformed fibroblasts were explored. Genistein and erbstatin, specific inhibitors of tyrosine kinase, had antiproliferative but not cytotoxic effects on the cells by themselves and synergistically enhanced the cytotoxic and antiproliferative effects of TNF-α. Immunoblot analysis with a monoclonal antiphosphotyrosine antibody revealed that TNF, administered for 5-180 min, induced tyrosine dephosphorylation of two pairs of membranal proteins, 34-36 kDa and 50-52 kDa, and potentiated tyrosine phosphorylation of a 115-kDa protein in both the cytosolic and membranal fractions of the cells. A very brief exposure (30 sec) to TNF induced rapid phosphorylation of several proteins, whereas genistein, but not inhibitors of other protein kinases, enhanced this effect of TNF. The results suggest that TNF activity could be potentiated by the inhibition of tyrosine phosphorylation and point to specific proteins that are dephosphorylated on tyrosine in response to TNF.
UR - http://www.scopus.com/inward/record.url?scp=0030452966&partnerID=8YFLogxK
U2 - 10.1089/jir.1996.16.1021
DO - 10.1089/jir.1996.16.1021
M3 - Article
AN - SCOPUS:0030452966
SN - 1079-9907
VL - 16
SP - 1021
EP - 1025
JO - Journal of Interferon and Cytokine Research
JF - Journal of Interferon and Cytokine Research
IS - 12
ER -