PMID: 23099021

Authors:

Nguyen JB, Modis Y

Title:

Crystal structure of the dimeric coiled-coil domain of the cytosolic nucleic acid sensor LRRFIP1.

Journal:

J Struct Biol. 2012 Oct 23. pii: S1047-8477(12)00274-2. doi:, 10.1016/j.jsb.2012.10.006.

Abstract:

LRRFIP1 binds cytoplasmic double-stranded DNA and RNA and interacts with FLI, the mammalian homolog of Drosophila flightless I, through a highly conserved 87-amino acid domain. Upon binding nucleic acid ligands, LRRFIP1 recruits and activates beta-catenin, leading to the IRF3-dependent production of type I interferon. However, the molecular mechanism of LRRFIP1 signaling is not well understood. Here we show that the FLI-interacting domain of LRRFIP1 forms a classic parallel, homodimeric coiled coil with 10 heptad repeats and 22 helical turns. The coiled coil domain is also a dimer in solution. However, a longer LRRFIP1 construct spanning the coiled coil and DNA binding domains assembles into higher order oligomers in solution. The structure of LRRFIP1-CC constitutes a valuable tool for probing the mechanism of LRRFIP1 signaling and for structural studies of larger LRRFIP1 constructs.