An 'immigration checkpoint’ inside human cells decides whether influenza virus gets in or is turned away. A protein TRIM62 tips that checkpoint in favour of the virus, according to new research1.
Researchers at the Indian Institute of Science Education and Research (IISER) Mohali found that the WASH complex — a group of proteins that recycle molecular cargo through endosomes — can either restrict or facilitate viral entry.
While several WASH components help influenza enter, FAM21 acts as a brake, creating a molecular checkpoint, says corresponding author Indranil Banerjee.
"When FAM21 connects WASH to another cellular complex called retromer present on the endosomes, it restricts viral entry. Influenza can only reach the cell surface, not into the cell."
The virus, however, can still sneak in with help from a host protein, TRIM62. Using a combination of imaging and biochemical assays, the researchers showed that TRIM62 disrupts the association between WASH and retromer, freeing WASH to support viral entry.
Cells lacking TRIM62 let far less virus in, and produced nearly 50-fold fewer infectious particles.
The study expands the list of potential targets for new antiviral strategies. ...