Poster abstracts

Poster number 30 submitted by Elizabeth DeLaney

The pattern recognition receptor RIG-I proofreads RNA duplex ends through its ATPase activity

Elizabeth DeLaney (Center for RNA Molecular Biology, Case Western Reserve University), Zhenrui Li (Center for RNA Molecular Biology, Case Western Reserve University), Andrea Putnam (Center for RNA Molecular Biology, Case Western Reserve University), Eckhard Jankowsky (Center for RNA Molecular Biology, Case Western Reserve University)

Abstract:
The mammalian innate immune system recognizes many viral RNAs through pathogen recognition receptors, including the RNA helicase RIG-I. Function of RIG-I in the innate immune response involves ATP and RIG-I binding to the end of RNA duplexes. However, RIG-I binding to duplex termini does not require ATP, and it is not clear how RNA recognition and ATP utilization are connected. To understand the link between RNA binding and ATP utilization, we examined in vitro how RIG-I couples RNA binding and ATP use for a series of defined model substrates. We find that ATPase activity is only activated by RNA duplexes containing a blunt end. RIG-I binds substrates without duplex termini, but ATPase activity is decreased by more than four orders of magnitude, compared to duplexes with a blunt end. Our observations further show that RIG-I oligomerizes on duplex RNAs, but only the terminal protomer bound to a blunt end hydrolyzes ATP. Collectively, our data indicate that RIG-I utilizes the ATP to proofread substrates for blunt duplex ends.

Keywords: RIG-I