Phosphatase PP2A promotes RTA dephosphorylation to impair KSHV lytic replication

Area of Science:

• Virology
• Molecular Biology
• Biochemistry

Background:

• Kaposi's Sarcoma-associated herpesvirus (KSHV) regulates latency and lytic replication via the RTA protein.
• RTA phosphorylation is crucial for its function, but its regulation is not fully understood.

Purpose of the Study:

• To investigate the role of RTA phosphorylation and dephosphorylation in KSHV lytic replication.
• To identify host factors interacting with RTA and modulating its activity.

Main Methods:

• Co-immunoprecipitation to identify RTA interacting proteins.
• Western blotting to assess protein phosphorylation.
• Viral replication assays to quantify progeny virions.
• Ubiquitin-proteasome pathway analysis.

Main Results:

• RTA interacts with PPP2R1A, a scaffold protein of phosphatase PP2A.
• PPP2R1A and PP2A activation suppress KSHV lytic replication by dephosphorylating RTA.
• KSHV RTA promotes PPP2R1A degradation via the ubiquitin-proteasome pathway to evade host control.

Conclusions:

• PPP2R1A is a novel binding partner of RTA, mediating RTA dephosphorylation by PP2A.
• This interaction suppresses KSHV lytic replication, offering potential antiviral targets.
• KSHV RTA employs a counter-strategy by degrading PPP2R1A.