The Hendra (HeV) and Nipah (NiV) viruses (Henipavirus genus) are zoonotic biosafety level 4 paramyxoviruses responsible for severe respiratory and neurological disease with a high case fatality (40-90%). In both NiV and HeV, the gene encoding the Phosphoprotein (P protein) also encodes the V and W proteins. The P, V and W proteins share a common N-terminal domain (NTD) and have unique and distinct C-terminal domains (CTD). The V and W proteins are two key players in the evasion of the host innate immune that act by either counteracting or inhibiting Interferon (IFN) signaling.
We previously showed that the NTD is intrinsically disordered both in isolation and in the context of the V protein, i.e. when appended upstream to the β-enriched CTD of V. We serendipitously discovered that the HeV V protein undergoes a liquid-to-hydrogel phase transition and identified the V region responsible for this phenomenon. This region, referred to as PNT3, was also found to be able to form amyloid-like fibrils. Noteworthy, Congo red staining experiments provided hints that these amyloid-like fibrils form not only in vitro but also in cellula after infection or transfection with PNT3- or V-encoding constructs.
Next, we showed that the ability to form fibrils is a property also shared by the intrinsically disordered W proteins. We showed that the cysteine oxidation state of the W proteins acts as a switch to generate either amorphous aggregates (when cysteine are reduced) or amyloid-like fibrils (when cysteines are engaged in intermolecular disulfide bonds). Importantly, we could demonstrate that W forms fibrils in the nuclei of transfected cells, with this ability being impaired in a W variant in which all cysteines are replaced with serines. Ongoing efforts aimed at elucidating the possible functional role of these fibrils will be discussed. Collectively, these studies provide the first evidence that Henipavirus V and W proteins are able to form amyloid-like fibrils in cellula, and the first clues on their functional impact. These findings hold promise for the rational design of new therapeutic approaches based on the inhibition of Henipavirus V/W fibrillation.
30 Maggio, 2025
The Hendra (HeV) and Nipah (NiV) viruses (Henipavirus genus) are zoonotic biosafety level 4 paramyxoviruses responsible for severe respiratory and neurological disease with a high case fatality (40-90%). In both NiV and HeV, the gene encoding the Phosphoprotein (P protein) also encodes the V and W proteins. The P, V and W proteins share a common N-terminal domain (NTD) and have unique and distinct C-terminal domains (CTD). The V and W proteins are two key players in the evasion of the host innate immune that act by either counteracting or inhibiting Interferon (IFN) signaling.
We previously showed that the NTD is intrinsically disordered both in isolation and in the context of the V protein, i.e. when appended upstream to the β-enriched CTD of V. We serendipitously discovered that the HeV V protein undergoes a liquid-to-hydrogel phase transition and identified the V region responsible for this phenomenon. This region, referred to as PNT3, was also found to be able to form amyloid-like fibrils. Noteworthy, Congo red staining experiments provided hints that these amyloid-like fibrils form not only in vitro but also in cellula after infection or transfection with PNT3- or V-encoding constructs.
Next, we showed that the ability to form fibrils is a property also shared by the intrinsically disordered W proteins. We showed that the cysteine oxidation state of the W proteins acts as a switch to generate either amorphous aggregates (when cysteine are reduced) or amyloid-like fibrils (when cysteines are engaged in intermolecular disulfide bonds). Importantly, we could demonstrate that W forms fibrils in the nuclei of transfected cells, with this ability being impaired in a W variant in which all cysteines are replaced with serines. Ongoing efforts aimed at elucidating the possible functional role of these fibrils will be discussed. Collectively, these studies provide the first evidence that Henipavirus V and W proteins are able to form amyloid-like fibrils in cellula, and the first clues on their functional impact. These findings hold promise for the rational design of new therapeutic approaches based on the inhibition of Henipavirus V/W fibrillation.