Molecular structure and function of the hemidesmosome: New insights and advances

Background Hemidesmosomes are a complex of proteins that play crucial role in the adhesion of the epithelial cells to the underlying basement membrane located in the undersurface of the basal keratinocytes. When any of the hemidesmosomal proteins are disrupted or mutated, it would lead to skin fragility or blisters causing abnormalities in protein-protein interaction and cell-cell communication. Material and methods By looking at the cDNA sequence that we have been provided with, the first step was to perform BLASTp. This was to find out the altered protein. Both sequences (normal and mutated patient), were identified to be related to collagen XVII protein a1. So far our Blast confirmed that Collagen XVII is the mutated protein in our patient. By comparing the two sequences the mutation is a nonsense mutation that converts Argenine (CGA) to a Stop codon (TGA).  Results Since Collagen XVII is a component of hemidesmosomes, if a mutation occurs in this protein (eg transmission from a C to a T), then this means that there is no production of this protein in skin, because the transcription will be prevented at the stop codon. This will lead to disruption of the hemidesmosome complex, which is unable to provide adhesion between the dermal-epidermal junction. As a result blisters will form between the layers. Conclusion The live patient in our study case has the homozygous recessive form of JEB which mean he has two copies of the defective gene, one from each parent, therefore showing symptoms.