Disease relevance of KRTAP26-1

• These data indicate that Clouston syndrome is not due to a defect in keratin or in a subset of keratin-associated proteins [1].
• This year, the first mutations in a keratin-associated protein, plectin, were shown to cause a variant of epidermolysis bullosa associated with late-onset muscular dystrophy (MD-EBS) [2].
• We report the melanocytic expression and alphaMSH up-regulation of 11 genes spanning 7 functional categories such as apoptosis, body weight control, intracellular transport, signal transduction, oncogenic transformation, transcription factors and genes coding for keratin associated proteins [3].

High impact information on KRTAP26-1

• To study the mechanism of keratin-associated predisposition to liver injury, we used mouse microarrays to examine genetic changes associated with hepatocyte keratin mutation and assessed the consequences of such changes [4].
• This work characterizes eight recently identified high glycine/tyrosine (HGT)-type KAP genes collectively designated Krtap16-n. These genes are shown to be integrated into a larger KAP gene domain on mouse chromosome 16 (MMU16) that is orthologous to a recently described HGT- and high sulfur (HS)-type KAP gene complex on human chromosome 21q22.11 [5].
• 1. This domain, present on the DNA accession numbers and, was approximately 535 kb in size and contained 17 high glycine-tyrosine and 7 high sulfur KAP genes, as well as 9 KAP pseudogenes [6].
• Based on amino acid sequence comparisons of the encoded proteins, the KAP genes could be divided into seven high glycine-tyrosine gene families (KAP6-KAP8, and KAP19-KAP22) and four high sulfur gene families (KAP11, KAP13, KAP15, and KAP23) [6].
• The high glycine-tyrosine genes described here appear to represent the complete set of this type of KAP genes present in the human genome [6].

Biological context of KRTAP26-1

• Characterization of a first domain of human high glycine-tyrosine and high sulfur keratin-associated protein (KAP) genes on chromosome 21q22.1 [6].
• Bioinformatic analyses of the promoter regions of the KAP10/KAP12 genes demonstrated several enhancer elements that were present in nearly all of the KAP genes [7].
• A cluster of 21 keratin-associated protein genes within introns of another gene on human chromosome 21q22.3 [8].
• Dot-matrix analysis revealed a significant similarity between these two KAP gene clusters [9].
• DNA sequence comparison revealed the common cluster structure consisting of 16 KAP genes for these three primates, but a significant difference was found in the baboon [10].

Anatomical context of KRTAP26-1

• In this study, cDNA clones encoding two novel keratin-associated proteins were isolated from human hair follicle mRNA [11].
• Hair fiber differentiation involves the expression of both hair keratin intermediate filament proteins and their associated proteins, termed keratin-associated proteins [11].
• These observations suggest that a certain keratin or keratin-associated protein is specifically expressed in a subpopulation of transitional and simple epithelial cells, and cultured cells derived from these epithelia [12].
• Continuing with melanocytes, Rouzaud's microarray analysis finds alpha-MSH up-regulating melanocyte genes involved in a wide range of biological functions involving cell survival, transformation, transcription, keratin associated proteins, and interestingly genes for body weight control [13].

Associations of KRTAP26-1 with chemical compounds

• Glycosidase digestion showed that KAP85 contains high mannose and complex oligosaccharides [14].
• Our results demonstrate in vitro evidence of a membrane-associated glycoprotein (KAP85) which may serve as an attachment site for filamentous K8/18 [14].
• Of these areas, only a proportion (70%) showed increased NBT staining, confirming the lack of correspondence between keratin-associated pimonidazole staining and reductase levels [15].
• These KAPs also showed high glycine and serine contents (average 24.30 and 21.13 mol%, respectively), distinguishing from other UHS/HS KAP families located on human chromosomes 17 and 21 [9].
• Based on the deduced amino acid sequences, all these KAP proteins were classified into an ultrahigh-sulfur (UHS) type KAP with high cysteine content (> 30 mol%) [9].

Co-localisations of KRTAP26-1

• Subcellular fractionation showed that KAP85 co-localizes with a plasma-membrane-enriched fraction that includes the transferrin receptor and KS-1 antigen [14].

Other interactions of KRTAP26-1

• We identified the human 78 kDa glucose-regulated protein (grp78) as a keratin-associated protein [16].
• This study is a report of a mosaic mutation in keratin 16 and also the association of a mutation in the V1 domain of a type I keratin associated with a human disease [17].
• Profilaggrin is an abundant component of keratohyalin granules and forms the precursor of filaggrin, the keratin associated protein of the stratum corneum [18].
• Keratin associated proteins are classified into two groups (high-cysteine and high glycine-tyrosine-rich polypeptides) according to the content of these amino acids [19].
• It is suggested that glycine-rich proteins with the chemical composition, immunological characteristics, and molecular weight of beta-keratins may represent the reptilian counterpart of keratin-associated proteins present in hairs, nails, hooves, and horns of mammals [20].

Analytical, diagnostic and therapeutic context of KRTAP26-1

• RT-PCR analysis of these KAP genes showed preferential expression in human hair root, suggesting these gene products are required for hair formation [9].
• More recently, we isolated two cDNA encoding novel members of the human keratin-associated protein 1 family (human keratin-associated protein 1.6 and human keratin-associated protein 1.7), and described their expression in the hair follicle by RNA in situ hybridization [21].

References