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The Emerging Roles of Viroporins in ER Stress Response and Autophagy Induction during Virus Infection.

Fung TS, Torres J, Liu DX - Viruses (2015)

Bottom Line: A number of viroporins have also been shown to localize to the endoplasmic reticulum (ER) and/or its associated membranous organelles.Both ER stress and autophagy are also known to modulate a wide variety of signaling pathways including pro-inflammatory and innate immune response, thereby constituting a major aspect of host-virus interactions.In this review, the potential involvement of viroporins in virus-induced ER stress and autophagy will be discussed.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore. tsfung@ntu.edu.sg.

ABSTRACT
Viroporins are small hydrophobic viral proteins that oligomerize to form aqueous pores on cellular membranes. Studies in recent years have demonstrated that viroporins serve important functions during virus replication and contribute to viral pathogenicity. A number of viroporins have also been shown to localize to the endoplasmic reticulum (ER) and/or its associated membranous organelles. In fact, replication of most RNA viruses is closely linked to the ER, and has been found to cause ER stress in the infected cells. On the other hand, autophagy is an evolutionarily conserved "self-eating" mechanism that is also observed in cells infected with RNA viruses. Both ER stress and autophagy are also known to modulate a wide variety of signaling pathways including pro-inflammatory and innate immune response, thereby constituting a major aspect of host-virus interactions. In this review, the potential involvement of viroporins in virus-induced ER stress and autophagy will be discussed.

No MeSH data available.


Related in: MedlinePlus

Mechanisms by which viroporins induce ER stress and autophagy. The ion channel activity of viroporins could alter the cellular calcium homeostasis, leading to a higher cytosolic [Ca2+], which leads to autophagy induction and activation of calcium-dependent cell death pathways. On the other hand, a lower ER luminal [Ca2+] reduces the ER folding capacity and leads to ER stress. ER stress induced by viroporins may also be mediated by membrane remodeling and delayed glycoprotein trafficking. The involvement of several viroporins, such as severe acute respiratory syndrome coronavirus (SARS-CoV) E and 3a protein, rotavirus NSP4 and influenza A virus (IAV) M2 protein, has been investigated recently. See text for detail.
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viruses-07-02749-f003: Mechanisms by which viroporins induce ER stress and autophagy. The ion channel activity of viroporins could alter the cellular calcium homeostasis, leading to a higher cytosolic [Ca2+], which leads to autophagy induction and activation of calcium-dependent cell death pathways. On the other hand, a lower ER luminal [Ca2+] reduces the ER folding capacity and leads to ER stress. ER stress induced by viroporins may also be mediated by membrane remodeling and delayed glycoprotein trafficking. The involvement of several viroporins, such as severe acute respiratory syndrome coronavirus (SARS-CoV) E and 3a protein, rotavirus NSP4 and influenza A virus (IAV) M2 protein, has been investigated recently. See text for detail.

Mentions: Numerous viruses have been demonstrated to cause ER stress and induce one or more branches of the UPR in the infected cells, including but not limited to influenza virus, dengue virus, Japanese encephalitis virus, HCV and coronaviruses (reviewed in [36,37]). For envelope viruses, induction of ER stress has been mainly attributed to the production of the large receptor binding proteins, such as the HA protein of influenza virus and the spike protein of SARS-CoV [38,39]. However, several properties of the viroporins suggest that they might also modulate the virus-induced ER stress response (Figure 3).


The Emerging Roles of Viroporins in ER Stress Response and Autophagy Induction during Virus Infection.

Fung TS, Torres J, Liu DX - Viruses (2015)

Mechanisms by which viroporins induce ER stress and autophagy. The ion channel activity of viroporins could alter the cellular calcium homeostasis, leading to a higher cytosolic [Ca2+], which leads to autophagy induction and activation of calcium-dependent cell death pathways. On the other hand, a lower ER luminal [Ca2+] reduces the ER folding capacity and leads to ER stress. ER stress induced by viroporins may also be mediated by membrane remodeling and delayed glycoprotein trafficking. The involvement of several viroporins, such as severe acute respiratory syndrome coronavirus (SARS-CoV) E and 3a protein, rotavirus NSP4 and influenza A virus (IAV) M2 protein, has been investigated recently. See text for detail.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488716&req=5

viruses-07-02749-f003: Mechanisms by which viroporins induce ER stress and autophagy. The ion channel activity of viroporins could alter the cellular calcium homeostasis, leading to a higher cytosolic [Ca2+], which leads to autophagy induction and activation of calcium-dependent cell death pathways. On the other hand, a lower ER luminal [Ca2+] reduces the ER folding capacity and leads to ER stress. ER stress induced by viroporins may also be mediated by membrane remodeling and delayed glycoprotein trafficking. The involvement of several viroporins, such as severe acute respiratory syndrome coronavirus (SARS-CoV) E and 3a protein, rotavirus NSP4 and influenza A virus (IAV) M2 protein, has been investigated recently. See text for detail.
Mentions: Numerous viruses have been demonstrated to cause ER stress and induce one or more branches of the UPR in the infected cells, including but not limited to influenza virus, dengue virus, Japanese encephalitis virus, HCV and coronaviruses (reviewed in [36,37]). For envelope viruses, induction of ER stress has been mainly attributed to the production of the large receptor binding proteins, such as the HA protein of influenza virus and the spike protein of SARS-CoV [38,39]. However, several properties of the viroporins suggest that they might also modulate the virus-induced ER stress response (Figure 3).

Bottom Line: A number of viroporins have also been shown to localize to the endoplasmic reticulum (ER) and/or its associated membranous organelles.Both ER stress and autophagy are also known to modulate a wide variety of signaling pathways including pro-inflammatory and innate immune response, thereby constituting a major aspect of host-virus interactions.In this review, the potential involvement of viroporins in virus-induced ER stress and autophagy will be discussed.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore. tsfung@ntu.edu.sg.

ABSTRACT
Viroporins are small hydrophobic viral proteins that oligomerize to form aqueous pores on cellular membranes. Studies in recent years have demonstrated that viroporins serve important functions during virus replication and contribute to viral pathogenicity. A number of viroporins have also been shown to localize to the endoplasmic reticulum (ER) and/or its associated membranous organelles. In fact, replication of most RNA viruses is closely linked to the ER, and has been found to cause ER stress in the infected cells. On the other hand, autophagy is an evolutionarily conserved "self-eating" mechanism that is also observed in cells infected with RNA viruses. Both ER stress and autophagy are also known to modulate a wide variety of signaling pathways including pro-inflammatory and innate immune response, thereby constituting a major aspect of host-virus interactions. In this review, the potential involvement of viroporins in virus-induced ER stress and autophagy will be discussed.

No MeSH data available.


Related in: MedlinePlus