To the editor

In calling attention to the several biomolecular entities whose names have been abbreviated `LAP', Wilson et al. raise an important issue. Acronyms and similar abbreviations are beneficial for a term that is used repeatedly in a publication; however, the existence of multiple entities that use the same abbreviation can cause confusion. It is for this reason that the universal standard of journals calls for explicit definition of an abbreviation at its first usage in a paper. This technique serves to dispel ambiguity that might arise.

In selecting an acronym for the leucine-rich repeat and PDZ-domain-containing (LAP) family of proteins, we searched the PubMed database, as well as the curated LocusLink nomenclature database (http://www.ncbi.nlm.nih.gov/LocusLink/), for previous uses of the abbreviation. As pointed out by Wilson et al., LAP has been used for over 35 years to abbreviate the names of individual proteins (leucine aminopeptidase, liver activating protein), a group of unrelated proteins that share binding partners (lamin-associated polypeptides), and an inherited human disorder (laryngeal adductor paralysis), as well as a gene-regulatory element (latency-associated or active promoter). We have used this acronym in a distinct, non-overlapping context: to describe a structurally related protein family. Along with the initial explicit definition, the usage `LAP protein family' serves to distinguish the family of proteins that includes Densin-180, Scribble, Let-413 and ERBIN from other biomolecules. Because this is a distinct usage we will continue to apply it.