SARS-CoV Nucleoprotein

Nucleoproteins are any proteins that are structurally associated with nucleic acids, either DNA or RNA. Typical nucleoproteines include ribosomes, nucleosomes, and viral nucleocapsid proteins.

Human SARS coronavirus Nucleoprotein

Packages the positive strand viral genome RNA into a helical ribonucleocapsid (RNP) and plays a fundamental role during virion assembly through its interactions with the viral genome and membrane protein M. Plays an important role in enhancing the efficiency of subgenomic viral RNA transcription as well as viral replication (PubMed:17210170).
May modulate transforming growth factor-beta signaling by binding host SMAD3 (PubMed:18055455).

Viral RNA genome packaging

Virion
Host endoplasmic reticulum-Golgi intermediate compartment
Host Golgi apparatus
Host cytoplasm, host perinuclear region
Located inside the virion, complexed with the viral RNA. Probably associates with ER-derived membranes where it participates in viral RNA synthesis and virus budding.

ADP-ribosylated. The ADP-ribosylation is retained in the virion during infection.
Phosphorylated on serine and threonine residues (By similarity).
Phosphorylated by host GSK3A and GSK3B. Phosphorylation allows recruitment of host RNA helicase DDX1 which facilitates template readthrough and enables longer subgenomic mRNA synthesis