Laminins are basement membrane components thought to mediate the attachment, migration and organization of cells into tissues during embryonic development by interacting with other extracellular matrix components. Laminin 5 is an isoform composed of three distinct subunits, alpha 3, beta 3 and gamma 2, which are bound to each other in a cross-shaped molecule by disulphide bonds. It is a complex glycoprotein thought to be involved in cell adhesion via integrin alpha-3/beta-1 in focal adhesion and integrin alpha-6/beta-4 in hemidesmosomes. It is also involved in signal transduction via tyrosine phosphorylation of pp125-FAK and p80, and differentiation of keratinocytes. 

The laminin alpha 3 subunit is also thought to be a component of laminin 6 and laminin 7.