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How Genomic and Structural Context Could Shape JAK-STAT Variant Pathogenicity

Published online by Cambridge University Press:  31 March 2026

Markus Hoffmann*
Affiliation:
Department of Biochemistry and Molecular & Cellular Biology, Georgetown University Medical Center, Washington, DC, USA
Hye Kyung Lee
Affiliation:
National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK), US National Institutes of Health, Bethesda, MD, USA
*
Corresponding author: Markus Hoffmann; Email: mh2437@georgetown.edu

Abstract

The Janus kinase (JAK)-Signal Transducer and Activator of Transcription (STAT) pathway is essential for cellular signal transduction, regulating immune responses, hematopoiesis, and cell proliferation. Dysregulation of JAK-STAT signaling due to genetic variations, particularly missense mutations, has been implicated in autoimmune disorders, cancers, and hematological malignancies. This study investigates missense mutations in JAK and STAT genes, focusing on disease-associated single nucleotide polymorphisms (SNPs) and ClinVar benign variants identified in the All of Us and COSMIC databases. We analyzed the distribution of these mutations across functional domains, their structural localization, and biochemical properties. We identified mutation hotspots within specific domains, highlighting their correlation with disease phenotypes. Structural mapping revealed that disease-associated SNPs predominantly localize in linker regions and at the boundaries of secondary structures, suggesting a significant impact on folding, stability, and function of JAK and STAT proteins. Additionally, we examined the genomic context of mutations and identified vulnerable sequences; for example, ‘GATC’. Furthermore, our analysis found no predominant association between potential CRISPR-Cas9 target sites and ClinVar benign/disease-associated SNPs. The analysis of amino acid sequence patterns surrounding mutations uncovered an enrichment of hydrophobic residues leucine (Leu), isoleucine (Ile), methionine (Met), and phenylalanine (Phe) in close proximity to disease-associated mutations. Our findings emphasize the importance of structural and biochemical context in determining pathogenicity. In this study, we provide a bioinformatic strategy for refining variant classification and understanding the roles of JAK-STAT pathway mutations in disease.

Information

Type
Article
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2026. Published by Cambridge University Press on behalf of International Society for Twin Studies
Figure 0

Figure 1. Figure 1 long description.Domain-specific distribution of missense mutations in JAK and STAT proteins and their associations with disease. The schematic representation of JAK (JAK2, JAK3, TYK2) and STAT (STAT1, STAT3, STAT4, STAT5B) proteins highlights the locations of missense mutations identified in the All of Us and COSMIC databases. Symbols indicate disease associations, including autoimmune diseases (turquoise circles), cancer/tumor (purple stars), infectious diseases (yellow triangles), blood disorders/hematopoietic system involvement (blue donuts), protective mutations against autoimmunity (green hexagons), and other genetic disorder order skin disorder (dark pink quarter of a circle). Mutations found in at least 20 individuals are labeled, with mutations found in All of Us (black font) or COSMIC (red font) and mutations found in All of Us and COSMIC are highlighted in bold red. This visualization provides insight into mutation clustering within functional domains. Protein domains are annotated as follows: STAT proteins include the N-terminal, coiled-coil, DNA-binding, linker, Src homology 2 (SH2), and transactivation (TAD) domains, while JAK proteins include the FERM (For protein 4.1, Ezrin, Radixin, and Moesin), SH2, pseudokinase, and kinase domains.

Figure 1

Figure 2. Structural analysis of disease-associated and ClinVar benign missense variants in the STAT proteins. The panel illustrates the secondary structure localization of disease-associated (left) and benign/likely benign (right) mutations mapped onto AlphaFold predicted protein structures.

Figure 2

Figure 3. Figure 3 long description.Structural analysis of disease-associated and ClinVar benign missense variants in the JAK proteins. The panel illustrates the secondary structure localization of disease-associated (left) and benign/likely benign (right) mutations mapped onto AlphaFold predicted protein structures.

Figure 3

Figure 4. Comparative analysis of amino acid patterns (one amino acid, two amino acid combinations, and three amino acid combinations out of three upstream and three downstream of the variant in All of Us or COSMIC) in benign and disease-associated variants. Amino acid compositions for benign variants are blue, and disease variants are red.

Figure 4

Figure 5. Enzyme restriction site analysis in proximity to disease-associated and ClinVar benign variants in JAK and STAT genes. (a,b) The top 25 restriction enzymes identified near disease-associated and benign variants, respectively. (c) Venn diagram illustrating the overlap of restriction sites found near disease-associated variants (red) and ClinVar benign variants (blue).

Figure 5

Figure 6. CRISPR cut site analysis in proximity to disease-associated and benign mutations. Venn diagram illustrating the overlap of Cas9 cut sites uniquely occurring in either disease-associated (red) or benign (blue) mutations.

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