HCMV C Nucleocapsid Translocation

Stable Identifier
Reaction [transition]
Homo sapiens
Related Species
Human cytomegalovirus
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Nucleocapsid C transport from the nucleus to the cytoplasm is carried out by a herpesvirus-conserved nuclear egress complex (NEC). The NEC is located at the inner nuclear membrane. This is probably one quality control step where preference is afforded to DNA-containing C capsids (nucleocapsids) over B capsids, possibly mediated by tegument proteins that associate with C capsids.The NEC is composed of a type II membrane-spanning component (NEC1, UL50 gene product) together with a nuclear lamina-interacting component (NEC2, UL53 gene product). This complex facilitates egress from the nucleus by recruiting cellular and viral protein kinases to phosphorylate and disrupt the nuclear lamina cage and allow nucleocapsid passage. Consistent with this, NEC1 or NEC2 mutant viruses in many herpesviruses including MCMV and HCMV accumulate nucleocapsids (C capsids) in the nucleus. In HCMV, host protein kinase C functions interchangeably with viral ppUL97/VPK, cellular p32, and the lamin B receptor in the NEC to phosphorylate lamins. Nucleocapsids are delivered to the cytoplasm with pp53/NEC2 remaining attached. ppUL53 accompanies the nucleocapsid as it is transported through the cytoplasm and becomes part of the tegument in mature virions. ppUL50/NEC1 remains in the nucleus and apparently cycles ppUL53.
Literature References
PubMed ID Title Journal Year
  Fields Virology

Knipe, DM, Howley, PM

Catalyst Activity

protein transmembrane transporter activity of Nuclear Egress Complex (NEC) [nucleoplasm]

This event is regulated
Name Identifier Synonyms
viral infectious disease DOID:934 Viral disease, virus infection, virus infection
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