Fig. 5: Model of RIG-I activation by Riplet.
From: The E3 ligase Riplet promotes RIG-I signaling independent of RIG-I oligomerization
a Composite structure of RIG-I recognition by full-length Riplet. The predicted structures of RING and CC are used to represent the domains missing from the cryo-EM structure of RIG-I:p3dsRNA24:Riplet complex. Two RIG-I molecules are colored in green and magenta, while the predicted and resolved domains of two Riplet in deepteal/wheat and cyan/yellow, respectively. b Working model of RIG-I activation by Riplet. Riplet is recruited to viral RNA-bound RIG-I by Riplet-PrySpry:RIG-I-Hel2 interactions, followed by Ub conjugation to RIG-I-CARDs mediated by the dimeric Riplet-RING domain. The second PrySpry domain could be in any of the three states: unbound form①, bound to apo RIG-I②, bound to RIG-I:RNA complex③, which is not expected to affect the process of Ub conjugation to the first RIG-I molecule.