Krtap24-1, also known as KAP24-1, is a gene encoding high-sulphur (HS) keratin-associated proteins (KAPs), which are structural components of hair and wool fibres, playing a crucial role in determining fibre properties [2,3]. In mammals, KAPs are grouped into 27 families, and Krtap24-1 is part of this complex network related to hair and wool structure and properties [2].

In goats, variation in the Krtap24-1 gene affects cashmere fibre diameter. Four different DNA sequences (A-D) and nine single-nucleotide polymorphisms (SNPs) were detected in 340 Longdong cashmere goats. Goats with genotype AA had a lower mean fibre diameter (MFD) than those with genotype AB, and AB had a lower MFD than BB [1]. In sheep, four allelic variants of Krtap24-1 were identified from 260 New Zealand Romney-cross sheep. The putative ovine KAP24-1 polypeptide had a moderate level of cysteine, but a high content of serine and tyrosine, along with two putative N-glycosylation sites and residues for possible O-glycosylation and/or phosphorylation [2]. In humans, KAP24.1 (product of Krtap24-1) was only present in the scalp, with a high content of serine, proline, and tyrosine, low cysteine, and specific expression in the middle/upper hair cuticle [3].

In conclusion, Krtap24-1 is essential for determining the properties of hair and wool fibres. The gene's polymorphisms in goats and sheep influence fibre-related traits, and in humans, it is involved in the structure of scalp hair. These findings from different species help understand the role of Krtap24-1 in hair-related biological processes, potentially providing insights for improving fibre-producing animals and understanding human hair-related conditions. [1,2,3]

References:

1. Wang, Jiqing, Zhou, Huitong, Luo, Yuzhu, Hu, Jiang, Hickford, Jon G H. 2019. Variation in the Caprine KAP24-1 Gene Affects Cashmere Fibre Diameter. In Animals : an open access journal from MDPI, 9, . doi:10.3390/ani9010015. https://pubmed.ncbi.nlm.nih.gov/30621287/

2. Zhou, Huitong, Gong, Hua, Yan, Wei, Luo, Yuzhu, Hickford, Jon G H. 2012. Identification and sequence analysis of the keratin-associated protein 24-1 (KAP24-1) gene homologue in sheep. In Gene, 511, 62-5. doi:10.1016/j.gene.2012.08.049. https://pubmed.ncbi.nlm.nih.gov/22995344/

3. Rogers, Michael A, Winter, Hermelita, Langbein, Lutz, Jave-Suarez, Luis F, Schweizer, Jürgen. 2007. Characterization of human KAP24.1, a cuticular hair keratin-associated protein with unusual amino-acid composition and repeat structure. In The Journal of investigative dermatology, 127, 1197-204. doi:. https://pubmed.ncbi.nlm.nih.gov/17235325/