TY  - GEN
TI  - RNA binding regulates TRIM25-mediated RIG-I
ubiquitination
Y1  - 2021///
AV  - public
CY  - Heidelberg
ID  - heidok28606
KW  - TRIM25
KW  -  RIG-I
KW  -  RNA binding proteins
KW  -  E3 ligases
KW  -  innate immunity
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/28606/
A1  - Haubrich, Kevin
N2  - TRIM25 is an E3 ligase of the tripartite motif protein family, that is best known for its function in innate immunity, where it activates the pattern recognition receptor RIG-I. More recently, it was identified as a putative RNA binding protein, though lacking domains with known RNA-binding potential. In this thesis, I present evidence that RNA binding is mediated by the coiled-coil (CC) and PRY/SPRY domain with possible contributions of the disordered linker connecting the domains. Using NMR spectroscopy and mutational analysis, I could map the RNA binding site on these domains. Small-angle X-ray scattering indicates that RNA-binding stabilizes an inherent, but weak interaction between these domains leading to a more rigid domain architecture possibly explaining the increase in ubiquitination activity in the presence of RNA observed by us and others. In line with that, mutants affecting RNA binding or the weak CC:PRY/SPRY interaction also reduced ubiquitination of the RIG-I caspase-activation and recruitment domains (CARDs). RNA binding in addition promotes phase-separation and association with RIG-I, as our results indicate that there is no direct protein-protein interaction between TRIM25 and RIG-I. This reconciles seemingly controversial results in recent studies and contributes to further unravel the mechanism behind the immune response activation upon viral infection.
ER  -