Hijacking of the O-GlcNAcZYME complex by the HTLV-1 Tax oncoprotein facilitates viral transcription.
Hijacking of the O-GlcNAcZYME complex by the HTLV-1 Tax oncoprotein facilitates viral transcription.
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DOI：
10.1371/journal.ppat.1006518
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发表时间：
2017-07
期刊：
影响因子：
6.7
通讯作者：
Issad T
中科院分区：
文献类型：
--
作者：
Groussaud D;Khair M;Tollenaere AI;Waast L;Kuo MS;Mangeney M;Martella C;Fardini Y;Coste S;Souidi M;Benit L;Pique C;Issad T
病毒Tax癌蛋白在人类T细胞嗜淋巴细胞病毒1型（HTLV-1）复制和HTLV-1相关病理学，特别是成人T细胞白血病中起关键作用。Tax通过将磷酸化CREB的二聚体募集到位于U3区（vCRE）内的cAMP反应元件，控制病毒5 'LTR的转录，从而增强其自身的表达。除了磷酸化，CREB也是O-GlcNAc酰化的靶标，O-GlcNAc酰化是另一种可逆的翻译后修饰，涉及广泛的疾病，包括癌症。O-GlcNAc化是在丝氨酸或苏氨酸残基上添加O-连接的-N-乙酰葡萄糖胺（O-GlcNAc）的过程，该过程由两种酶控制：O-GlcNAc转移酶（OGT），其将O-GlcNAc转移到蛋白质上，O-GlcNAc酶（OGA），其将其去除。我们发现，OGA的mRNA和蛋白质的表达水平增加HTLV-1转化的T细胞相比，对照T细胞系，而OGT的表达是不变的。然而，较高的OGA产生与OGA比活性的降低一致，表明HTLV-1转化的T细胞产生高水平的活性较低形式的OGA。将Tax引入HEK-293 T细胞或Tax阴性HTLV-1转化的TL-om 1 T细胞足以抑制OGA活性并增加总O-GlcNAc酰化，而OGT活性没有任何变化。此外，Tax与OGT/OGA复合物相互作用并抑制OGT结合的OGA的活性。OGA的药理学抑制增加CREB O-GlcNAc化以及通过Tax的HTLV-1-LTR反式激活和CREB向LTR的募集。此外，野生型CREB的过表达而不是在先前描述的O-GlcNAc化位点上突变的CREB蛋白增强Tax介导的LTR反式激活。最后，OGT和OGA都被招募到LTR。这些发现揭示了Tax和O-GlcNAc化途径之间的相互作用，并确定了参与Tax依赖性反式激活复合物组装的新的关键分子。人类嗜T淋巴细胞病毒1型（HTLV-1）是唯一与癌症相关的人类逆转录病毒。事实上，HTLV-1是成人T细胞白血病的原因，这是一种CD 4 + T淋巴细胞的侵袭性恶性增殖。调节蛋白Tax控制HTLV-1从5 'LTR的转录，驱动所有病毒蛋白的表达，包括其自身，但反义产物HBZ除外。除了在HTLV-1表达中的关键作用外，Tax还作为一种癌蛋白，能够在体外诱导T细胞永生化和在小鼠中诱导肿瘤形成。在这项研究中，我们报告说，税收相互作用的O-GlcNAczyme OGT/OGA复合物，催化O-GlcNAcylation，翻译后修饰往往在癌症中失调。我们发现Tax与OGT/OGA复合物相互作用并抑制OGA的活性，从而增加细胞O-GlcNAc化。引人注目的是，我们发现CREB（Tax在病毒启动子上募集的细胞转录因子）的O-GlcNAc化以Tax依赖性方式增加。此外，增加CREB O-GlcNAc化强烈增强Tax诱导的LTR反式激活以及CREB与病毒启动子的结合。最后，OGT和OGA都是反式激活复合物的一部分。这些发现为Tax依赖性LTR反式激活机制提供了新的线索，并可能为靶向HTLV-1表达的新分子干预开辟道路。
The viral Tax oncoprotein plays a key role in both Human T-cell lymphotropic virus type 1 (HTLV-1)-replication and HTLV-1-associated pathologies, notably adult T-cell leukemia. Tax governs the transcription from the viral 5’LTR, enhancing thereby its own expression, via the recruitment of dimers of phosphorylated CREB to cAMP-response elements located within the U3 region (vCRE). In addition to phosphorylation, CREB is also the target of O-GlcNAcylation, another reversible post-translational modification involved in a wide range of diseases, including cancers. O-GlcNAcylation consists in the addition of O-linked-N-acetylglucosamine (O-GlcNAc) on Serine or Threonine residues, a process controlled by two enzymes: O-GlcNAc transferase (OGT), which transfers O-GlcNAc on proteins, and O-GlcNAcase (OGA), which removes it. In this study, we investigated the status of O-GlcNAcylation enzymes in HTLV-1-transformed T cells. We found that OGA mRNA and protein expression levels are increased in HTLV-1-transformed T cells as compared to control T cell lines while OGT expression is unchanged. However, higher OGA production coincides with a reduction in OGA specific activity, showing that HTLV-1-transformed T cells produce high level of a less active form of OGA. Introducing Tax into HEK-293T cells or Tax-negative HTLV-1-transformed TL-om1 T cells is sufficient to inhibit OGA activity and increase total O-GlcNAcylation, without any change in OGT activity. Furthermore, Tax interacts with the OGT/OGA complex and inhibits the activity of OGT-bound OGA. Pharmacological inhibition of OGA increases CREB O-GlcNAcylation as well as HTLV-1-LTR transactivation by Tax and CREB recruitment to the LTR. Moreover, overexpression of wild-type CREB but not a CREB protein mutated on a previously described O-GlcNAcylation site enhances Tax-mediated LTR transactivation. Finally, both OGT and OGA are recruited to the LTR. These findings reveal the interplay between Tax and the O-GlcNAcylation pathway and identify new key molecular actors involved in the assembly of the Tax-dependent transactivation complex. Human T-cell lymphotropic virus type 1 (HTLV-1) is the only human retrovirus associated to a cancer. Indeed, HTLV-1 is responsible for adult T-cell leukemia, an aggressive malignant proliferation of CD4+ T lymphocytes. The regulatory protein Tax governs HTLV-1 transcription from the 5’LTR, driving expression of all viral proteins, including itself, at the exception of the antisense product HBZ. Besides this critical role in HTLV-1 expression, Tax acts as an oncoprotein able to induce T-cell immortalization in vitro and tumor formation in mice. In this study, we report that Tax interacts with the O-GlcNAczyme OGT/OGA complex that catalyzes O-GlcNAcylation, a post-translational modification often deregulated in cancers. We found that Tax interacts with the OGT/OGA complex and inhibits the activity of OGA, increasing thereby cellular O-GlcNAcylation. Strikingly, we found that O-GlcNAcylation of CREB, the cellular transcription factor recruited by Tax on the viral promoter, is increased in a Tax-dependent manner. Moreover, increased CREB O-GlcNAcylation strongly enhances Tax-induced LTR transactivation as well as CREB binding to the viral promoter. Finally, both OGT and OGA are part of the transactivation complex. These findings shed new light on the mechanism of Tax-dependent LTR transactivation and may open the way to new molecular interventions targeting HTLV-1 expression.
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影响因子：
8
作者：
Kim, Y-M;Geiger, T. R.;Egan, D. I.;Sharma, N.;Nyborg, J. K.
通讯作者：
Nyborg, J. K.
影响因子：
4.8
作者：
Goldberg, HJ;Whiteside, CI;Fantus, IG
通讯作者：
Fantus, IG
影响因子：
4.8
作者：
Carrillo, Luz D.;Froemming, Joshua A.;Mahal, Lara K.
通讯作者：
Mahal, Lara K.
影响因子：
5.8
作者：
Blanquart, Christophe;Achi, Josepha;Issad, Tarik
通讯作者：
Issad, Tarik
DOI：
10.1073/pnas.1013822108
发表时间：
2011-02-15
影响因子：
11.1
作者：
Daou, Salima;Mashtalir, Nazar;Affar, El Bachir
通讯作者：
Affar, El Bachir