Two nuclear localization signals regulate intracellular localization of the duck enteritis virus UL13 protein

Regulation of alphaherpesvirus protein via post-translational phosphorylation

An alphaherpesvirus carries dozens of viral proteins in the envelope, tegument and capsid structure, and each protein plays an indispensable role in virus adsorption, invasion, uncoating and release. After infecting the host, a virus eliminates unfavourable factors via multiple mechanisms to escape or suppress the attack of the host immune system. Post-translational modification of proteins, especially phosphorylation, regulates changes in protein conformation and biological activity through a series of complex mechanisms. Many viruses have evolved mechanisms to leverage host phosphorylation systems to regulate viral protein activity and establish a suitable cellular environment for efficient viral replication and virulence. In this paper, viral protein kinases and the regulation of viral protein function mediated via the phosphorylation of alphaherpesvirus proteins are described. In addition, this paper provides new ideas for further research into the role played by the post-translational modification of viral proteins in the virus life cycle, which will be helpful for understanding the mechanisms of viral infection of a host and may lead to new directions of antiviral treatment.

PACS-1 contains distinct motifs for nuclear-cytoplasmic transport and interacts with the RNA-binding protein PTBP1 in the nucleus and cytosol

Phosphofurin acidic cluster sorting protein 1 (PACS-1) is canonically a cytosolic trafficking protein, yet recent reports have described nuclear roles for PACS-1. Herein, we sought to define the nuclear transport mechanism of PACS-1. We demonstrate that PACS-1 nucleocytoplasmic trafficking is dependent on its interaction with the nuclear transport receptors importin alpha 5 and exportin 1. PACS-1 nuclear entry and exit are defined by a nuclear localization signal (NLS, residues 311-318) and nuclear export signal (NES3, residues 366-375). Mutation of the PACS-1 NLS and NES3 altered the localization of a complex formed between PACS-1 and an RNA-binding protein, polypyrimidine tract-binding protein 1. Overall, we identify the nuclear localization mechanism of PACS-1 and highlight a potential role for PACS-1 in RNA-binding protein trafficking.