Affordable Access

Novel keratin 16 mutations and protein expression studies in pachyonychia congenita type 1 and focal palmoplantar keratoderma.

Authors
Type
Published Article
Journal
Experimental dermatology
Publication Date
Volume
9
Issue
3
Pages
170–177
Identifiers
PMID: 10839714
Source
Medline

Abstract

Pachyonychia congenita type 1 (PC-1) is an autosomal dominant ectodermal dysplasia characterized by nail dystrophy, focal non-epidermolytic palmoplantar keratoderma (FNEPPK) and oral lesions. We have previously shown that mutations in keratin 16 (K16) cause fragility of specific epithelia resulting in phenotypes of PC-1 or FNEPPK alone. Here, we report 2 novel mutations in K16 causing distinct phenotypes. A heterozygous missense mutation (L124R) was detected in a kindred with PC-1. In a family where mild FNEPPK was the only phenotype, a 23 bp deletion and a separate 1 bp deletion downstream were found in exon 6: [1244-1266del; 1270delG]. At the protein level, these mutations remove 8 residues and substitute 2 residues in the helix termination motif (HTM) of the K16 polypeptide. The HTM sequence is conserved in all known intermediate filament proteins and for convenience, this complex mutation was designated deltaHTM. Transient expression of K16 cDNAs carrying either the L124R or the deltaHTM mutation in epithelial cell line PtK2 produced aggregation of the keratin cytoskeleton. However, the aggregates observed with the deltaHTM mutation were morphologically different and appeared to be less disruptive to the endogenous cytoskeleton. Therefore, loss of the HTM sequence may render this mutant K16 less capable of contributing to filament assembly and decrease its dominant-negative effect, resulting in the milder FNEPPK phenotype.

There are no comments yet on this publication. Be the first to share your thoughts.

Statistics

Seen <100 times
0 Comments