Department of Biochemistry and Biophysics, University of Rochester Medical Center, 601 Elmwood Ave., Rochester, NY 14642, USA.
J Virol. 2011 Jan;85(2):705-14. doi: 10.1128/JVI.01557-10. Epub 2010 Nov 17.
Viruses depend on the host cell to provide the energy and biomolecular subunits necessary for production of viral progeny. We have previously reported that human cytomegalovirus (HCMV) infection induces dramatic changes to central carbon metabolism, including glycolysis, the tricarboxylic acid (TCA) cycle, fatty acid biosynthesis, and nucleotide biosynthesis. Here, we explore the mechanisms involved in HCMV-mediated glycolytic activation. We find that HCMV virion binding and tegument protein delivery are insufficient for HCMV-mediated activation of glycolysis. Viral DNA replication and late-gene expression, however, are not required. To narrow down the list of cellular pathways important for HCMV-mediated [corrected] activation of glycolysis, we utilized pharmaceutical inhibitors to block pathways reported to be both involved in metabolic control and activated by HCMV infection. We find that inhibition of calmodulin-dependent kinase kinase (CaMKK), but not calmodulin-dependent kinase II (CaMKII) or protein kinase A (PKA), blocks HCMV-mediated activation of glycolysis. HCMV infection was also found to target calmodulin-dependent kinase kinase 1 (CaMKK1) expression, increasing the levels of CaMKK1 mRNA and protein. Our results indicate that inhibition of CaMKK has a negligible impact on immediate-early-protein accumulation yet severely attenuates production of HCMV viral progeny, reduces expression of at least one early gene, and blocks viral DNA replication. Inhibition of CaMKK did not affect the glycolytic activation induced by another herpes virus, herpes simplex virus type 1 (HSV-1). Furthermore, inhibition of CaMKK had a much smaller impact on HSV-1 replication than on that of HCMV. These data suggest that the role of CaMKK during the viral life cycle is, in this regard, HCMV specific. Taken together, our results suggest that CaMKK is an important factor for HCMV replication and HCMV-mediated glycolytic activation.
病毒依赖宿主细胞提供产生病毒后代所需的能量和生物分子亚基。我们之前曾报道，人巨细胞病毒（HCMV）感染会引起中央碳代谢的剧烈变化，包括糖酵解、三羧酸（TCA）循环、脂肪酸生物合成和核苷酸生物合成。在这里，我们探讨了 HCMV 介导的糖酵解激活的相关机制。我们发现 HCMV 病毒粒子结合和衣壳蛋白传递不足以介导 HCMV 诱导的糖酵解激活。然而，病毒 DNA 复制和晚期基因表达并不需要。为了缩小对 HCMV 介导的糖酵解激活至关重要的细胞途径列表，我们利用药物抑制剂来阻断代谢控制和 HCMV 感染激活的途径。我们发现，抑制钙调蛋白依赖性激酶激酶（CaMKK），而不是钙调蛋白依赖性激酶 II（CaMKII）或蛋白激酶 A（PKA），可以阻断 HCMV 介导的糖酵解激活。HCMV 感染也被发现靶向钙调蛋白依赖性激酶激酶 1（CaMKK1）的表达，增加 CaMKK1 mRNA 和蛋白的水平。我们的结果表明，CaMKK 抑制对早期蛋白积累几乎没有影响，但严重抑制 HCMV 病毒后代的产生，降低至少一个早期基因的表达，并阻断病毒 DNA 复制。CaMKK 抑制并不影响另一种疱疹病毒，单纯疱疹病毒 1（HSV-1）诱导的糖酵解激活。此外，CaMKK 抑制对 HSV-1 复制的影响比对 HCMV 的影响要小得多。这些数据表明，在病毒生命周期中，CaMKK 的作用在这方面是 HCMV 特异性的。总之，我们的结果表明，CaMKK 是 HCMV 复制和 HCMV 介导的糖酵解激活的重要因素。
