Scholarlink

<p>ORF3a, the most&#xa0;abundantly expressed accessory protein of SARS-CoV-2, plays an essential role in virus egress by inactivating lysosomes through their deacidification. However, the mechanism underlying this&#xa0;process remains unclear. While seminal studies suggested ORF3a being a cation-selective channel (i.e., viroporin), recent works disproved this conclusion. To unravel the potential function of ORF3a, here we employed a multidisciplinary approach including patch-clamp electrophysiology, videoimaging, molecular dynamics (MD)&#xa0;simulations, and electron microscopy. Preliminary structural analyses and&#xa0;patch-clamp recordings in HEK293 cells rule out ORF3a functioning&#xa0;as either viroporin or proton (H<sup>+</sup>) channel. Conversely, videoimaging experiments demonstrate that ORF3a mediates the transmembrane transport of water. MD&#xa0;simulations identify the tetrameric assembly&#xa0;of ORF3a as the functional water transporter, with a putative selectivity filter for water permeation that includes two essential&#xa0;asparagines, N82 and N119. Consistent with this, N82L and N82W mutations abolish ORF3a-mediated water permeation. Finally, ORF3a expression in HEK293 cells leads to lysosomal volume increase, mitochondrial damage, and accumulation of intracellular membranes, all alterations reverted by the N82W mutation. We propose a novel function for ORF3a as a lysosomal water-permeable channel, essential for lysosome deacidification and inactivation, key steps to promote virus egress.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

SARS-CoV-2 ORF3a accessory protein is a water-permeable channel that induces lysosome swelling

  • 期刊论文

  • 出版模式：

    开放获取

  • 发表日期：

    2025年2月4日

查看全文
  • Antonio Michelucci,
  • Luigi Sforna,
  • Riccardo Focaia,
  • Maria Vittoria Leonardi,
  • Angela Di Battista,
  • Giorgia Rastelli,
  • Simone Vespa,
  • Simona Boncompagni,
  • Manlio Di Cristina,
  • Luigi Catacuzzeno

摘要

ORF3a, the most abundantly expressed accessory protein of SARS-CoV-2, plays an essential role in virus egress by inactivating lysosomes through their deacidification. However, the mechanism underlying this process remains unclear. While seminal studies suggested ORF3a being a cation-selective channel (i.e., viroporin), recent works disproved this conclusion. To unravel the potential function of ORF3a, here we employed a multidisciplinary approach including patch-clamp electrophysiology, videoimaging, molecular dynamics (MD) simulations, and electron microscopy. Preliminary structural analyses and patch-clamp recordings in HEK293 cells rule out ORF3a functioning as either viroporin or proton (H+) channel. Conversely, videoimaging experiments demonstrate that ORF3a mediates the transmembrane transport of water. MD simulations identify the tetrameric assembly of ORF3a as the functional water transporter, with a putative selectivity filter for water permeation that includes two essential asparagines, N82 and N119. Consistent with this, N82L and N82W mutations abolish ORF3a-mediated water permeation. Finally, ORF3a expression in HEK293 cells leads to lysosomal volume increase, mitochondrial damage, and accumulation of intracellular membranes, all alterations reverted by the N82W mutation. We propose a novel function for ORF3a as a lysosomal water-permeable channel, essential for lysosome deacidification and inactivation, key steps to promote virus egress.