Schematic representation of the components of the hemidesmosomes and of the
protein. (A) Schematic representation of the components of the hemidesmosomes (adapted from http://xtal.cicancer.org/research.html). (B) Comparison between the structure of the mutant (predicted) and wild-type integrin β4 subunit (http://www.uniprot.org/uniprot/P16144). The wild-type integrin β4 comprises: (i) an extracellular region that contains the N-terminal plexin-semaphorin-integrin (PSI) and von Willebrand factor type A (VWFA) domains as well as a cysteine-rich repeat region; (ii) a transmembrane domain and (iii) a cytoplasmic region that includes a calx-beta (calx- β) domain and four fibronectin III-like domains (FnIII-1 to 4). The transmembrane domain and cytoplasmic region are predicted to be totally absent in the mutated β4 subunit.