SIZE: 590 amino acids; 62378 Da
SUBUNIT: Heterotetramer of two type I and two type II keratins. Keratin-5 associates with keratin-14. Interacts with TCHP.
DISEASE: SwissProt: P13647 # Defects in KRT5 are a cause of epidermolysis bullosa simplex (EBS) [MIM:131760, 131800, 131900, 131960]. Epidermolysis bullosa (EB) is a mendelian disorder that can be inherited in an autosomal dominant or recessive form and is characterized by blistering or erosion of the skin and mucous membranes as a result of mild trauma. The incidence at birth of all types of the disease is about 1:50,000. Three major clinical subgroups are: simplex (EBS), junctional (EBJ), and dystrophic (EBD). EBS is by far the most prevalent (65%) and it is characterized by blistering within the basal cell layer. Junctional and dystrophic EB are characterized by blistering in the plane of the lamina lucida of the basement membrane zone and below the dermal-epidermal basement membrane at the level of the anchoring fibrils, respectively. & Defects in KRT5 are a cause of epidermolysis bullosa simplex Dowling-Meara type (DM-EBS) [MIM:131760]. DM-EBS is the most severe of the simplex group and is characterized by generalized herpetiform blistering, milia formation, dystrophic nails, and mucous membrane involvement. & Defects in KRT5 are the cause of epidermolysis bullosa simplex with migratory circinate erythema [MIM:609352]. EBS with migratory circinate erythema is milder than the DM-EBS phenotype but involves an unusual migratory circinate erythema with multiple vesicles on the area affected by the erythema. The lesions, which appeared from birth primarily on the hands, feet, and legs but spared the nails, ocular epithelia, and mucosae, healed with brown pigmentation but no scarring. Electron microscopy findings were distinct from those seen in the DM-EBS, with no evidence of tonofilament clumping. & Defects in KRT5 are a cause of epidermolysis bullosa simplex Weber-Cockayne type (WC-EBS) [MIM:131800]. WC-EBS is characterized by blistering in palmar and plantar areas of the skin. & Defects in KRT5 are a cause of epidermolysis bullosa simplex Koebner type (K-EBS) [MIM:131900]. K-EBS is characterized by generalized blistering as the Dowling-Meara type; the phenotype however is less severe. & Defects in KRT5 are the cause of epidermolysis bullosa simplex with mottled pigmentation (MP-EBS) [MIM:131960]. MP-EBS is characterized by additional reticular hyperpigmentation. & Defects in KRT5 are the cause of Dowling-Degos disease (DDD) [MIM:179850]; also known as Dowling-Degos-Kitamura disease or reticulate acropigmentation of Kitamura. DDD is an autosomal dominant genodermatosis. Affected individuals develop a postpubertal reticulate hyperpigmentation that is progressive and disfiguring, and small hyperkeratotic dark brown papules that affect mainly the flexures and great skin folds. Patients usually show no abnormalities of the hair or nails.
SIMILARITY: SwissProt: P13647 ## Belongs to the intermediate filament family.
MISCELLANEOUS: There are two types of cytoskeletal and microfibrillar keratin: I (acidic; 40-55 kDa) and II (neutral to basic; 56-70 kDa).