Characterization of ER-localized Activity of HHV-8 Interleukin-6

描述（由申请方提供）：人类疱疹病毒8型（HHV-8）与卡波西肉瘤、多中心Castleman病和原发性渗出性淋巴瘤（PEL）的病因相关。该病毒编码白细胞介素-6（病毒IL-6，vIL-6）的同源物，并且该病毒细胞因子已经涉及HHV-8相关肿瘤的发展和发病机制。vIL-6是PEL细胞生长和存活所需的，并且已知其定位于这些细胞的内质网（ER），在那里其能够介导其促生长和存活作用。vIL-6在潜伏感染的PEL细胞中介导这些活性的机制尚不清楚。然而，我们最近已经确定了一种新的相互作用伙伴的vIL-6，维生素K环氧化物还原酶复合物亚基1变体2（VKORC 1v 2），它也定位于ER和功能，以促进PEL细胞的生长和生存的机制，涉及其与vIL-6的相互作用。在酵母双杂交筛选和随后的共沉淀试验中，VKORC 1v 2也显示出与硫氧还蛋白样蛋白1（TMX 1）相互作用，TMX 1是一种已知参与二硫键还原的ER定位蛋白。ER定位和VKORC 1v 2与TMX 1的相互作用表明，这些蛋白质可能在vIL-6的折叠和/或调节ER应激反应中发挥作用。最近的研究还表明IL-6信号转导物gp 130是PEL细胞生长和维持所必需的，尽管vIL-6在此过程中的特定作用是不确定的。 进程尚未确定。本F31申请拟在分子水平上进一步表征vIL-6：VKORC 1v 2相互作用，确定VKORC 1v 2和TMX 1与vIL-6活性的联系，并阐明vIL-6：gp 130信号传导对PEL细胞生长和活力的贡献和机制。通过了解vIL-6在病毒生物学和发病机制中作用的分子机制，可以识别和利用新的靶点来治疗BEL和其他HHV-8相关疾病。

DESCRIPTION (provided by applicant): Human herpesvirus 8 (HHV-8) has been etiologically linked to Kaposi sarcoma, multicentric Castleman's disease, and primary effusion lymphoma (PEL). The virus encodes a homolog of interluekin-6 (viral IL-6, vIL-6), and this viral cytokine has been implicated in development and pathogenesis of HHV-8 associated neoplasias. vIL-6 is required for PEL cell growth and survival, and it is known to localize to the endoplasmic reticulum (ER) of these cells where it is competent to mediate its pro-growth and survival effects. The mechanism by which vIL-6 mediates these activities in latently infected PEL cells is unclear. However, we have recently identified a novel interaction partner of vIL-6, vitamin K epoxide reductase complex subunit 1 variant 2 (VKORC1v2), which also localizes to the ER and functions to promote PEL cell growth and survival by a mechanism involving its interaction with vIL-6. In a yeast two-hybrid screen and subsequently by co-precipitation assay, VKORC1v2 was also shown to interact with thioredoxin-like protein 1 (TMX1), an ER-localized protein known to participate in the reduction of disulfide bonds. ER localization and interaction of VKORC1v2 with TMX1 suggest that these proteins may play a role in the folding of vIL-6 and/or in regulating the ER stress response. Recent studies have also indicated that the IL-6 signal transducer, gp130, is required for the growth and maintenance of PEL cells although the specific role of vIL-6 in this process has not been determined. This F31 application proposes to further characterize the vIL-6:VKORC1v2 interaction at the molecular level, to determine the connection of VKORC1v2 and TMX1 with vIL-6 activity, and to elucidate the contribution and mechanism of vIL-6:gp130 signaling to PEL cell growth and viability. By understanding the molecular mechanisms of vIL-6 effects in virus biology and pathogenesis, new targets may be identified and exploited for therapeutic benefit to treat PEL and other HHV-8 associated diseases.