Uitto J, Pulkkinen L
Department of Dermatology, Jefferson Medical College, Philadelphia, PA 19107, USA.
Mol Biol Rep. 1996;23(1):35-46. doi: 10.1007/BF00357071.
Ultrastructural examination of the cutaneous basement membrane zone (BMZ) reveals the presence of several attachment structures, which are critical for integrity of the stable association of epidermis and dermis. These include hemidesmosomes which extend from the intracellular compartment of the basal keratinocyte to the underlying basement membrane where they complex with anchoring filaments, thread-like structures traversing the lamina lucida. At the lower portion of dermal-epidermal attachment zone, anchoring fibrils extend from the lamina densa to the papillary dermis, where they associate with basement membrane-like structures, known as anchoring plaques. Molecular cloning of the cutaneous BMZ components has allowed elucidation of the structural features of the proteins which constitute these attachment structures. Specifically, hemidesmosomes have been shown to consist of at least four distinct proteins. The intracellular hemidesmosomal inner plaque is comprised of the 230-kD bullous pemphigoid antigen (BPAG1), and plectin, a high-molecular weight cytomatrix protein, encoded by the corresponding gene, PLEC1. The transmembrane component of the hemidesmosomes consists of the 180-kD bullous pemphigoid antigen (BPAG2), a collagenous protein also known as type XVII collagen (COL17A1), as well as of the basal keratinocyte-specific integrin alpha 6 beta 4. The anchoring filaments consist predominantly of laminin 5 with three constitutive subunit polypeptides, the alpha 3, beta 3 and gamma 2 chains, which is associated with laminin 6 with the chain composition alpha 3, beta 1 and gamma 1. Also associated with anchoring filaments is a novel protein, ladinin, which serves as autoantigen in the linear IgA disease, and the corresponding gene, LAD1, has been mapped to human chromosome 1. Finally, the major, if not the exclusive, component of anchoring fibrils is type VII collagen, encoded by the gene (COL7A1) which consists of 118 distinct exons, the largest number of exons in any gene published thus far. Collectively, the cutaneous basement membrane zone is a complex continuum of macromolecules which form a network providing the stable association of the epidermis to the underlying dermis. Thus, genetic lesions resulting in abnormalities in any part of this network could result in a blistering skin disease, such as epidermolysis bullosa.
皮肤基底膜带（BMZ）的超微结构检查显示存在几种附着结构，这些结构对于表皮和真皮稳定结合的完整性至关重要。这些结构包括半桥粒，其从基底角质形成细胞的细胞内部分延伸至下方的基底膜，在那里它们与锚定丝结合，锚定丝是穿过透明板的丝状结构。在真皮 - 表皮附着区的下部，锚定原纤维从致密板延伸至乳头真皮，在那里它们与称为锚定斑的基底膜样结构相关联。皮肤BMZ成分的分子克隆使得构成这些附着结构的蛋白质的结构特征得以阐明。具体而言，已证明半桥粒至少由四种不同的蛋白质组成。细胞内半桥粒内板由230-kD大疱性类天疱疮抗原（BPAG1）和由相应基因PLEC1编码的高分子量细胞基质蛋白网蛋白组成。半桥粒的跨膜成分由180-kD大疱性类天疱疮抗原（BPAG2）组成，BPAG2是一种胶原质蛋白，也称为XVII型胶原（COL17A1），以及基底角质形成细胞特异性整合素α6β4。锚定丝主要由层粘连蛋白5组成，层粘连蛋白5具有三种组成亚基多肽，即α3、β3和γ2链，其与链组成为α3、β1和γ1的层粘连蛋白6相关联。与锚定丝相关的还有一种新蛋白，层粘连蛋白结合蛋白，它是线状IgA疾病中的自身抗原，相应的基因LAD1已被定位到人类染色体1上。最后，锚定原纤维的主要成分（如果不是唯一成分的话）是VII型胶原，由基因（COL7A1）编码，该基因由118个不同的外显子组成，是迄今为止已发表的任何基因中外显子数量最多的。总的来说，皮肤基底膜带是一个复杂的大分子连续体，形成一个网络，为表皮与下方真皮的稳定结合提供支持。因此，导致该网络任何部分异常的基因损伤都可能导致水疱性皮肤病，如大疱性表皮松解症。
