Led by Pinghui Feng, Ph.D., associate professor of molecular microbiology and immunology at the Keck School of Medicine of USC, the team found that herpesvirus proteins activate retinoic acid-induced gene I (RIG-I) by removal of an amino group from the glutamine and asparagine amino acids through a process called deamidation. RIG-I is a cellular receptor that recognizes RNA derived from invading pathogens. Prior to this study, it was unclear whether RIG-I — whose activation is central to the body’s innate immune defense response — could be activated by a component other than viral RNA. This is the first example wherein host immune defense is activated by an enzymatic activity, implying that deamidation can be a highly regulated process, reshaping the conventional notion that deamidation is a non-specific process associated with protein decay. The team also identified the first bona-fide enzyme that causes protein deamidation in eukaryotes.
source : http://www.sciencedaily.com/releases/2015/04/150402183534.htm