辛德毕斯病毒感染的鸡细胞细胞膜中钠钾ATP酶活性的抑制作用。

Inhibition of Na+K+ATPase activity in membranes of Sindbis virus-infected chick cells.

作者信息

Ulug E T, Garry R F, Bose H R

机构信息

Section of Virology and Oncology, Kansas State University, Manhattan, 66506-4901, USA.

出版信息

Virology. 1996 Feb 15;216(2):299-308. doi: 10.1006/viro.1996.0065.

DOI:10.1006/viro.1996.0065

PMID:8607259

Abstract

Alterations in intracellular concentrations of Na+ and K+ in Sindbis virus-infected cells result largely from inhibition of ouabain-sensitive Na+K+ATPase (Na+ pump) activity. Here we report that membrane preparations derived from Sindbis virus-infected chick cells exhibit reduced Na+K+ATPase activity, indicating that limitation of cellular factors is not responsible for inhibition of ion transport. In vitro phosphorylation of the Na+K+ATPase by [32P]orthophosphate or [gamma 32P]ATP is unaltered in membranes of Sindbis virus-infected cells, indicating that a loss of specific enzymatic functions unrelated to formation of Na+ pump phosphoenzyme intermediates occurs during the course of viral infection. However, phosphoenzyme intermediates of the Na+K+ATPase prepared from membranes of Sindbis virus-infected cells are inherently less stable than those prepared with membranes of uninfected cells. The instability of these intermediates in vitro is correlated with an altered capacity of the Na+ pump to transport monovalent cations into virus-infected cells. 22Na+ transport studies reveal enhanced ouabain-sensitive Na+ uptake by Sindbis virus-infected cells, suggesting that the Na+ pump may catalyze enhanced Na+-Na+ exchange in the infected cells. These results indicate that the capacity of the Na+K+ATPase to discriminate between binding of extracellular Na+ and K+ is specifically altered during the course of infection by Sindbis virus.

摘要

辛德毕斯病毒感染的细胞内 Na⁺ 和 K⁺ 浓度的改变主要是由于哇巴因敏感的 Na⁺K⁺ATP 酶（Na⁺ 泵）活性受到抑制。在此我们报告，源自辛德毕斯病毒感染的鸡细胞的膜制剂显示出降低的 Na⁺K⁺ATP 酶活性，这表明细胞因子的限制并非离子转运抑制的原因。在辛德毕斯病毒感染的细胞的膜中，用 [³²P] 正磷酸盐或 [γ - ³²P]ATP 对 Na⁺K⁺ATP 酶进行的体外磷酸化未发生改变，这表明在病毒感染过程中，与 Na⁺ 泵磷酸酶中间体形成无关的特定酶功能丧失。然而，从辛德毕斯病毒感染的细胞的膜制备的 Na⁺K⁺ATP 酶的磷酸酶中间体在本质上比从未感染细胞的膜制备的中间体更不稳定。这些中间体在体外的不稳定性与 Na⁺ 泵将单价阳离子转运到病毒感染细胞中的能力改变相关。²²Na⁺ 转运研究表明，辛德毕斯病毒感染的细胞对哇巴因敏感的 Na⁺ 摄取增强，这表明 Na⁺ 泵可能催化感染细胞中增强的 Na⁺ - Na⁺ 交换。这些结果表明，在辛德毕斯病毒感染过程中，Na⁺K⁺ATP 酶区分细胞外 Na⁺ 和 K⁺ 结合的能力发生了特异性改变。