Fig. 1

Human FURIN gene and furin protein structures. a The human FURIN gene consists of 16 exons and encodes eight different transcript variants driven by three known promoters, P1, P1A and P1B. Exons are shown as green boxes and introns are shown as lines. The red boxes indicate the three promoter regions. The blue arrows indicate the positions where different transcripts start. The red arrow indicates the translational start, and the start codon (ATG) and stop codon (TGA) are marked with dotted lines. b Furin protein contains an N-terminal signal peptide, a prodomain, a subtilisin-like catalytic domain, a middle P-domain, a cysteine-rich region, a transmembrane helix domain and a C-terminal cytoplasmic domain