Structure of the Act1 adaptor protein. Act1 contains two TRAF-binding motifs (residues EESE (35 to 42) and EESE (333 to 337)), a helix-loop-helix (HLH) domain (residues 135 to 190), a SEFIR domain (residues 394 to 574), and a coil-coiled (C-C) domain (residues 470 to 500). The SNPs (SNP1 (D10N or Asp10Asn) = rs33980500 and SNP2 (R74W or Arg74Trp) = rs13190932) and the experimentally determined phosphorylation locations are shown above the Act1 domain structure. Act1, nuclear factor-kappa-B activator 1; SEFIR, similar expression to fibroblast growth factor genes/interleukin-17 receptor; SNP, single-nucleotide polymorphism; TRAF, tumor necrosis factor receptor-associated factor.