Angiomotin-Like 1 Links Paramyxovirus M Proteins to NEDD4 Family Ubiquitin Ligases

Area of Science:

• Virology
• Cell Biology
• Molecular Biology

Background:

• Paramyxovirus budding relies on cellular ESCRT machinery.
• Angiomotin-like 1 (AMOTL1) was identified as a host factor binding to parainfluenza virus 5 (PIV5) matrix (M) protein.
• AMOTL1 contains L/PPXY motifs, enabling interaction with WW domain proteins like NEDD4 family members.

Purpose of the Study:

• To investigate the role of AMOTL1 in linking paramyxovirus M proteins to NEDD4 ubiquitin ligases.
• To determine if paramyxoviruses use AMOTL1 as an indirect recruitment strategy for NEDD4 family proteins during budding.
• To explore the necessity of AMOTL1 for budding when M proteins possess PPXY late domains.

Main Methods:

• Three-way co-immunoprecipitation (co-IP) experiments to assess protein interactions.
• Co-expression of viral M proteins, AMOTL1, and NEDD4 family proteins.
• Mutational analysis by attaching a PPXY late domain to the PIV5 M protein.

Main Results:

• AMOTL1 successfully linked PIV5 and mumps virus M proteins with NEDD4 family proteins (NEDD4-1, NEDD4L, NEDL1) when co-expressed.
• AMOT and AMOTL2 could not substitute for AMOTL1 due to their inability to bind paramyxovirus M proteins.
• Directly attaching a PPXY late domain to the PIV5 M protein eliminated the requirement for AMOTL1.

Conclusions:

• Paramyxoviruses employ a novel strategy using AMOTL1 to indirectly recruit NEDD4 ubiquitin ligases for viral budding.
• This indirect recruitment mechanism complements direct recruitment via PPXY late domains utilized by other enveloped viruses.
• Understanding this host factor recruitment is key to comprehending paramyxovirus particle release.