Sufu (suppressor of Fused Gli/Ci) is a repressor of the Gli and Ci transcription factors of the Hedgehog signalling cascade. It functions by binding to these proteins and preventing their translocation to the nucleus. Sufu possesses an extended dumb-bell-like shape, with a short linker functioning as a hinge connecting the two globular NTD and CTD domains. The Sufu C-terminal domain binds to the N-terminal of Gli/Ci, while the N-terminal of Sufu binds to the C-terminal of Gli/Ci. This dual binding mechanism is likely to be an evolutionary advancement in this signalling cascade, which is not present in bacterial homologues.

This superfamily represents the C-terminal domain of suppressor of fused. It folds into a domain that comprises a four-stranded and a six-stranded beta-sheet, both with mixed topologies, which are connected by two antiparallel alpha-helices.

INTERPRO:IPR024314,DOI:10.1038/ncomms3608,DOI:10.1107/S0907444913028473