The Kaposi's Sarcoma-associated Herpesvirus (KSHV)-encoded G-protein coupled receptor (vGPCR) is an oncoprotein that is implicated in KSHV-associated malignancies. We previously revealed vGPCR incorporates sulfate...The Kaposi's Sarcoma-associated Herpesvirus (KSHV)-encoded G-protein coupled receptor (vGPCR) is an oncoprotein that is implicated in KSHV-associated malignancies. We previously revealed vGPCR incorporates sulfate groups within its extracellular N-terminal tyrosine residues (Y26 and Y28) and that this tyrosine sulfation is crucial for its tumorigenicity in nude mice. hGRO-binds vGPCR in a sulfotyrosine-dependent manner and promotes its tumorigenicity through autocrine signaling. Interestingly, an unsulfated vGPCR mutant (yydd-vGPCR) attenuated the tumor growth triggered by hGRO-α . In this study, the extracellular N-terminus of vGPCR (wt-vGN) and an unsulfated vGPCR mutant (yydd-vGN) were individually secreted, expressed and purified. A radioactive labeling assay demonstrated that wt-vGN but not yydd-vGN incorporated [ 35 S]-sulfate. In nude mice, NIH3T3 cells expressing yydd-vGN but not wt-vGN could significantly inhibit the tumor growth triggered by hGRO-α . All our data support the conclusion that the unsulfated extracellular N-terminus of vGPCR reduces the tumorigenicity of hGRO-α .展开更多
基金supported by the National Natural Science Foundation of China (81171583,31272634)the Program for New Century Excellent Talents in University (NCET-11-0971)+2 种基金the Scientific Research Foundation for the Returned Overseas Chinese Scholars/State Education Ministry(2011-1568-1)funds from Hunan Province (12JJ1005,12A088)the Excellent Talent Program of Hunan Normal University (ET31004)
文摘The Kaposi's Sarcoma-associated Herpesvirus (KSHV)-encoded G-protein coupled receptor (vGPCR) is an oncoprotein that is implicated in KSHV-associated malignancies. We previously revealed vGPCR incorporates sulfate groups within its extracellular N-terminal tyrosine residues (Y26 and Y28) and that this tyrosine sulfation is crucial for its tumorigenicity in nude mice. hGRO-binds vGPCR in a sulfotyrosine-dependent manner and promotes its tumorigenicity through autocrine signaling. Interestingly, an unsulfated vGPCR mutant (yydd-vGPCR) attenuated the tumor growth triggered by hGRO-α . In this study, the extracellular N-terminus of vGPCR (wt-vGN) and an unsulfated vGPCR mutant (yydd-vGN) were individually secreted, expressed and purified. A radioactive labeling assay demonstrated that wt-vGN but not yydd-vGN incorporated [ 35 S]-sulfate. In nude mice, NIH3T3 cells expressing yydd-vGN but not wt-vGN could significantly inhibit the tumor growth triggered by hGRO-α . All our data support the conclusion that the unsulfated extracellular N-terminus of vGPCR reduces the tumorigenicity of hGRO-α .
