Figure 2. Schematic representation of the highly diverging N-terminus of laminin chains. Three basic structural domains found in the N-terminus of the laminin chains are the LN (laminin N-terminal), LE (laminin-type epidermal growth (EGF) factor-like) and L4/LF (laminin IV) domains. The names (in black), location and size of the various domains are indicated for the different laminin chains. Each L4 domain corresponds to a long stretch of residues inserted between cysteine residues 3 and 4 of one LE domain. In this case the L4 and LE domains should be considered as one single domain which is emphasized by using the same color. In contrast the LF domains are located between two LE repeats as in the α3B, α5, β1 and β2 chains. When L4 or LF globular domains interrupt the arrays of repeating LE domains, they determine stretches named LEa, LEb and LEc. The numbering of the LE domains starts with 1 for each stretch (LEa1, LEa2, …; LEb1, LEb2, etc…). For example, the N-terminus of the laminin α1 chain starts with one LN domain, followed by a first array of four LE domains (LEa1 to LEa4), then one globular domain L4a (consisting of a long stretch of residue inserted within one LE domain), followed by a second array of eight LE domains (LEb1 to LEb8), another globular domain L4b (consisting of a long stretch of residue inserted within one LE domain), and finally a stretch of three LE domains (LEc1 to LEc3). In contrast the N-terminus of the laminin α3A chain consists of three LE domains only. This nomenclature adopted in 2005⁹ is indicated to the left of each diagram. It should be noted that in the UniProt (http://uniprot.org) data bank, numbering of the LE domains is different. It is based on the total number of LE domains as indicated with the small gray lettering right to the various diagrams.