CorpusHuman Anatomy
IntegumentaryMembrane

Dermoepidermal junction

Also known as: basement membrane zone, DEJ, epidermal basement membrane, rete ridges

The dermoepidermal junction is the undulating basement membrane zone that binds the epidermis to the dermis through hemidesmosomes, laminin, collagen IV and anchoring fibrils.

Show on body map Skin — Layers and Appendages

Overview

Seen in section, the boundary between epidermis and dermis is wavy: downward epidermal (rete) ridges interdigitate with upward dermal papillae. This interlocking increases the contact area for nutrient diffusion and resists shearing. Molecularly the junction is a multilayered basement membrane zone: basal keratinocytes attach through hemidesmosomes (plectin, BP230, integrin α6β4 and the transmembrane collagen BP180/collagen XVII) to the lamina lucida (laminin-332), the lamina densa (collagen IV, nidogen, perlecan) and finally, through anchoring fibrils of collagen VII, to the papillary dermis.

Each molecule is the target of an inherited or autoimmune blistering disease, making the DEJ one of the most examined "molecular anatomy" topics in dermatology. With age the junction flattens, reducing adhesion — which is why elderly skin tears so easily.

Location

Interface between stratum basale and papillary dermis throughout the skin; also surrounds hair follicles and sweat ducts.

Parts & subdivisions

  1. Hemidesmosomes
    Attach basal keratinocyte keratin filaments (K5/K14) via plectin and BP230 to transmembrane integrin α6β4 and BP180 (collagen XVII).
  2. Lamina lucida
    Electron-lucent layer crossed by anchoring filaments of laminin-332 (laminin 5).
  3. Lamina densa
    Electron-dense sheet of type IV collagen network with nidogen and perlecan.
  4. Sublamina densa (anchoring fibrils)
    Type VII collagen fibrils loop from the lamina densa around dermal collagen and anchoring plaques.
  5. Rete ridges and dermal papillae
    Interdigitating folds that increase surface area; most pronounced in thick skin and areas of high friction.

Anatomy

Histology

PAS-positive line beneath the stratum basale on light microscopy; ultrastructurally lamina lucida (≈40 nm), lamina densa (≈50 nm) and sublamina densa zone.

Function

  • Anchors epidermis to dermis and resists shear
  • Selective filter for molecules and cells passing between dermis and epidermis
  • Scaffold guiding re-epithelialisation during wound healing

Clinical significance

Bullous pemphigoid

IgG autoantibodies to BP180 and BP230 trigger complement activation and eosinophil-rich inflammation, splitting the lamina lucida: tense subepidermal blisters, usually in the elderly; linear IgG/C3 on direct immunofluorescence; Nikolsky sign negative.

Epidermolysis bullosa

Inherited fragility: simplex (keratin 5/14, split within basal cells), junctional (laminin-332 or collagen XVII, split in lamina lucida) and dystrophic (collagen VII, split below lamina densa with scarring and milia).

Compiled from standard anatomy and physiology references — see the Integumentary System sources. For education only; not medical advice.