Zika Virus Enters Soma of Neuron through NGF/TrkA-Like Endosomal Signaling Pathway

Infection with the Zika virus results in severe neurological disease in adults or congenital Zika syndrome in newborns. We employed the domain search strategy to study the Zika virus glycoprotein E in this work. The results revealed that immature E contains a NGF domain (“MNKCYIQIMDLGHMCDATMSYECPMLDEGVEPDDVDCWCNTTSTWVVYGTCHH”) and is capable of interacting with TrkA. The E/TrkA complex increased E's interaction with receptors such as Axl and facilitated Zika virus endocytosis via clathrin. Rab5 retrograded transmission of Zika virus-containing E/TrkA endosomal signals to neuronal soma. Rab7 helped dissociation of E/TrkA in late acidic endosomes, and then E became mature after the NGF domain was cut. After membrane fusion with the endosome, the Zika virus was released into the neuron cell body. It showed only the immature E protein of Zika had NGF activity. The retrograde trafficking of endosomal signals (E/TrkA) similar to NGF/TrkA enabled Zika virus to infect neuronal cells. E's interference with the TrkA signal impaired neuronal cell growth and results in neuronal cell apoptosis.