Interaction between herpes simplex virus type 1 IE63 protein and cellular protein p32

Area of Science:

• Virology
• Molecular Biology
• Cellular Biology

Background:

• Herpes simplex virus type 1 (HSV-1) immediate-early gene IE63 (ICP27) is a key regulatory protein.
• IE63 controls viral and cellular transcriptional and posttranscriptional processes, including splicing inhibition.
• Previous studies identified hnRNP K and CK2 as IE63 binding partners.

Purpose of the Study:

• To identify novel protein partners of HSV-1 IE63.
• To investigate the role of IE63 and its partners in regulating RNA splicing.
• To understand IE63's contribution to viral replication mechanisms.

Main Methods:

• Yeast two-hybrid assay to identify protein interactions.
• Coimmunoprecipitation assays to confirm interactions in infected cells.
• Recombinant protein binding assays.
• Analysis of protein localization and phosphorylation.

Main Results:

• The cellular protein p32 was identified as a novel binding partner of HSV-1 IE63.
• A complex involving p32, hnRNP K, and CK2 was formed in the presence of IE63 in infected cells.
• p32 was phosphorylated by CK2 within this complex.
• IE63 expression altered p32's cellular distribution, causing some colocalization in the nucleus.
• p32's known association with splicing factors and splicing inhibition was highlighted.

Conclusions:

• HSV-1 IE63 interacts with cellular p32, forming a complex that includes hnRNP K and CK2.
• This IE63-p32 complex likely plays a role in regulating or disrupting pre-mRNA splicing.
• The modulation of splicing by IE63 and p32 may contribute to host cell shutoff and facilitate viral RNA export.