DIDS blocks a chloride-dependent current that is mediated by the 2B protein of enterovirus 71

Abstract

Enterovirus 71 (EV71), which belongs to the genus Enterovirus of the family Picornaviridae, is one of the major pathogens that cause hand, foot and mouth disease, primarily in infants and young children. In recent years, epidemic and sporadic outbreaks of neurovirulent EV71 infections have been reported in many countries and regions, including Japan, China and Taiwan [1]. However, there is still no effective antiviral treatment against severe EV71 infections, and no vaccine is available.During their life cycle, viruses can induce many changes in their host cells including increased plasma membrane permeability [2]. Although its detailed mechanism remains largely unknown, this effect on the plasma membrane could be due to the expression of many virusencoded proteins [3][4][5]. The expression of protein 2B from polioviruses and coxsackieviruses can increase the permeability of the cell membrane to the translational inhibitor hygromycin B [6,7]. A recent study that focused on protein 2B from coxsackievirus B3 (CVB3) showed that 2B can facilitate virus release by increasing the concentration of free cytosolic Ca 2+ [8]. However, little is known about 2B proteins from other enteroviruses, and the detailed mechanisms of how 2B changes cellular ion homeostasis and, thus, promotes virion release remain unclear.Because the 2B protein of CVB3 can form homodimers and homotetramers that are located primarily in the cell membrane system, including the Golgi complex [9, 10], we asked whether the 2B proteins of EV71 might share similar characteristics. To address this question, the sequences of the 2B genes from these two viruses were compared. These sequences have relatively high similarity, especially within their two transmembrane domains (TM1 and TM2), structures that are essential for the function of viroporins (Supplementary information, Figure S1A). Next, we examined the subcellular localization of the EV71 2B protein in human rhabdomyosarcoma (RD) cells and found that it colocalized with the Golgi complex (Supplementary information, Figure S1B).

Porcine deltacoronavirus (PDCoV) modulates calcium influx to favor viral replication

“…These viral proteins are termed as viroporins. Some viroporins have been identified, such as the non-structural protein 4 (NSP4) of rotavirus, the matrix protein 2 (M2) of IAV, the p7 protein of HCV, the viral protein U (Vpu) of HIV and the protein 2B (P2B) of picornavirus (Hyser et al, 2013;Ewart et al, 2002;Luik et al, 2009;Stouffer et al, 2008;Xie et al, 2011). These viroporins have been demonstrated to enhance the passage of ions and small molecules through membranes to favor viral replication (Nieva et al, 2012).…”

Viroporins: structure and biological functions

“…It has also been reported that this compound can target HIV-1 Vpu and inhibit viral release from macrophages 126 . Recently, a classic anion exchanger inhibitor, DIDS (4,4ʹ-diisothiocyano-2,2ʹ-stilbenedisulphonic acid), was reported to partially suppress the chloride conductance that is mediated by the enterovirus P2B viroporin in X. laevis oocytes and to block virus production in human cells 127 .…”

The ORF4a protein of human coronavirus 229E functions as a viroporin that regulates viral production

“…To assess the putative ion channel activity of ORF4a, healthy Xenopus oocytes were injected with C-terminally HA-tagged ORF4a complementary RNA (cRNA), and oocyte membrane currents were recorded using a twoelectrode voltage clamp. All procedures followed those described previously [24]. Macroscopic currents were recorded in the ORF4a-HA cRNAinjected oocytes and were compared to uninjected oocytes (control oocytes) of the same batch (Fig.…”