{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n Keratin-associated protein 6-1 (KRTAP6-1) is a high glycine/tyrosine type II protein expressed in a hair‐follicle–specific manner that plays a critical structural role in fiber formation. It is a key component of the protein matrix that cross‐links with keratin intermediate filaments to stabilize the hair (or wool) shaft and contribute to its mechanical strength. Expression studies have shown that KRTAP6-1 is specifically localized within the hair cortex—particularly in the cortical cells forming the brush‐end—suggesting it contributes to anchoring the fiber structure and influences fiber properties such as diameter and curvature. Promoter analyses further indicate that its transcription is finely regulated by multiple transcription factors; for example, NF‑κB acts as an enhancer for KRTAP6-1 expression, while other factors (e.g., POU2F1) may repress its activity. Moreover, the challenges encountered in recombinant production due to its cysteine-rich composition underscore the specialized nature of this protein. Together, these findings support the concept that KRTAP6-1 is integral to hair fiber formation, influencing both the structural integrity and the morphological characteristics of the fiber."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "4"}]}, {"type": "t", "text": "\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Othman Rechiche, Jeffrey E Plowman, Duane P Harland, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Expression and purification of high sulfur and high glycine-tyrosine keratin-associated proteins (KAPs) for biochemical and biophysical characterization."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Protein Expr Purif (2018)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.pep.2017.12.006"}], "href": "https://doi.org/10.1016/j.pep.2017.12.006"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "29391282"}], "href": "https://pubmed.ncbi.nlm.nih.gov/29391282"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Zu Yang, Kai Cui, Yuanyuan Zhang, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Transcriptional regulation analysis and the potential transcription regulator site in the extended KAP6.1 promoter in sheep."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Biol Rep (2014)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1007/s11033-014-3485-y"}], "href": "https://doi.org/10.1007/s11033-014-3485-y"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "24990691"}], "href": "https://pubmed.ncbi.nlm.nih.gov/24990691"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Jin Zhao, Qiang Ding, Lan Li, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Deletions in the "}, {"type": "a", "children": [{"type": "t", "text": "i"}], "href": "i"}, {"type": "t", "text": "KAP6-1"}, {"type": "a", "children": [{"type": "t", "text": "/i"}], "href": "/i"}, {"type": "t", "text": " gene are associated with fiber traits in cashmere-producing goats."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Anim Biotechnol (2022)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1080/10495398.2021.1881529"}], "href": "https://doi.org/10.1080/10495398.2021.1881529"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "33583337"}], "href": "https://pubmed.ncbi.nlm.nih.gov/33583337"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Zhidong Yu, Steven W Gordon, Allan J Nixon, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Expression patterns of keratin intermediate filament and keratin associated protein genes in wool follicles."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Differentiation (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.diff.2008.10.009"}], "href": "https://doi.org/10.1016/j.diff.2008.10.009"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19272529"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19272529"}]}]}]}