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 .
高迁移率族蛋白B1（high mobility group box-1protein,HMGB1,NP_002119）是普遍存在于真核细胞核内且与非组蛋白染色体相结合的蛋白,因为在聚丙烯酰胺凝胶电泳中迁移速度很快而得名[1]。HMGB1是维持生命活动所必需的蛋白,敲除小鼠的HMGB1基因后,其在出生后不久便死亡[2]。近年来发现HMGB1是一种晚期炎性因子[3],其可释放到胞外作为一种重要的信号因子参与细胞分化、
