Nucleocytoplasmic trafficking of Nipah virus W protein involves multiple discrete interactions with the nuclear import and export machinery

Paramyxoviruses replicate in the cytoplasm with no obvious requirement to interact with the nucleus. Nevertheless, the W protein of the highly lethal bat-borne paramyxovirus Nipah virus (NiV) is known to undergo specific targeting to the nucleus, mediated by a single nuclear localisation signal (NLS) within the C-terminal domain. Here, we report for the first time that additional sites modulate nucleocytoplasmic localisation of W. We show that the N-terminal domain interacts with importin α1 and contributes to nuclear accumulation of W, indicative of a novel N-terminal NLS. We also find that W undergoes exportin-1 mediated nuclear export, dependent on a leucine at position 174. Together, these data enable significant revision of the generally accepted model of W trafficking, with implications for understanding of the mechanisms of NiV immune evasion.