Laminin332

Laminin-332, also known as laminin-5 in older literature, is a heterotrimeric extracellular matrix glycoprotein that forms part of the basement membrane in epithelial tissues. It consists of the alpha-3 (LAMA3), beta-3 (LAMB3), and gamma-2 (LAMC2) chains, and its name reflects the chain composition 3-3-2.

Laminin-332 is a major component of the basement membrane in stratified epithelia, including skin and oral mucosa. It contributes to adhesion of epithelial sheets to the underlying stroma and to basement membrane assembly by linking with integrins (notably α6β4 and α3β1) as well as nidogen and collagen IV networks. It also influences cell migration and wound healing and participates in signaling through integrin receptors.

Clinical significance is highlighted by its involvement in hereditary blistering disorders. Mutations in LAMA3, LAMB3, or LAMC2 can cause junctional epidermolysis bullosa (JEB), a heritable skin fragility disorder characterized by blistering after minor trauma. Some severe forms include pyloric atresia. The most common pathogenic variants are found in LAMB3 and LAMC2, while LAMA3 mutations can also contribute to JEB phenotypes of varying severity.

Laminin-332 and disease extend beyond inherited conditions. In cancer and tissue remodeling, abnormal expression or processing of laminin-332, particularly the gamma-2 chain, has been linked to increased cell migration and invasion. Proteolytic processing of the gamma-2 chain can generate fragments that promote motility and contribute to remodeling of the extracellular matrix.

Biology and naming: laminin-332 is one of many laminin isoforms; its name reflects its chain composition, while laminin-5 is an older designation still encountered in the literature.