A simplification of the laminin nomenclature is presented. Laminins are multidomain heterotrimers composed of α, β and γ chains. Previously, laminin trimers were numbered with Arabic numerals in the order discovered, that is laminins-1 to -5. We introduce a new identification system for a trimer using three Arabic numerals, based on the α, β and γ chain numbers. For example, the laminin with the chain composition α5β1γ1 is termed laminin-511, and not laminin-10. The current practice is also to mix two overlapping domain and module nomenclatures. Instead of the older Roman numeral nomenclature and mixed nomenclature, all modules are now called domains. Some domains are renamed or renumbered. Laminin epidermal growth factor-like (LE) domains are renumbered starting at the N-termini, to be consistent with general protein nomenclature. Domain IVb of α chains is named laminin 4a (L4a), domain IVa of α chains is named L4b, domain IV of γ chains is named L4, and domain IV of β chains is named laminin four (LF). The two coiled–coil domains I and II are now considered one laminin coiled-coil domain (LCC). The interruption in the coiled-coil of β chains is named laminin β-knob (Lβ) domain. The chain origin of a domain is specified by the chain nomenclature, such as α1L4a. The abbreviation LM is suggested for laminin. Otherwise, the nomenclature remains unaltered.
