STAT3 mutations, predominantly in the DNA-binding domain (DBD) and Src-homology 2 domain (SH2D), cause rare cases of immunodeficiency, malignancy, and autoimmunity. The exact mechanisms by which these mutations abrogate or enhance STAT3 function are not completely understood. Here, we examined how loss-of-function (LOF) and gain-of-function (GOF) STAT3 mutations within the DBD and SH2D affect monomer and homodimer protein stability as well as their effect on key STAT3 activation events, including recruitment to phosphotyrosine (pY) sites within peptide hormone receptors, tyrosine phosphorylation at Y705, dimerization, nuclear translocation, and DNA binding. The DBD LOF mutants showed reduced DNA binding when homodimerized, whereas the DBD GOF mutants showed increased DNA binding. DBD LOF and GOF mutants showed minimal changes in other STAT3 functions or in monomer or homodimer protein stability. However, SH2D LOF mutants demonstrated reduced conformational stability as either monomers or homodimers, leading to decreased pY-peptide recruitment, tyrosine phosphorylation, dimerization, nuclear localization, and DNA binding. In contrast, cancer-causing SH2D GOF mutants showed increased STAT3 homodimer stability, which increased their DNA binding. Of note, a small-molecule inhibitor of STAT3 that targets the tyrosine phosphopeptide-binding pocket within the STAT3 SH2D potently inhibited cell proliferation driven by STAT3 SH2D GOF mutants. These findings indicate that the stability of STAT3 protein monomer and homodimer is critical for the pathogenesis of diseases caused by SH2D LOF and GOF mutations and suggest that agents that modulate STAT3 monomer and/or homodimer protein stability may have therapeutic value in diseases caused by these mutations.
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http://dx.doi.org/10.1182/blood.2021015330 | DOI Listing |
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January 2025
School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan province, P.R. China. Electronic address:
FOXM1 is the "Achilles' heel" of cancers and hence the potential therapeutic target for anticancer drug discovery. In this work, we selected high affinity peptides against the protein of human DNA binding domain of FOXM1 (FOXM1-DBD) from the disulfide-constrained, phage displayed random cyclic heptapeptide library Ph.D.
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Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Key Laboratory of Zoonosis, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110866, China; The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, 120 Dongling Road, Shenyang 110866, China. Electronic address:
Tripartite motif-containing proteins (TRIMs), comprising the greatest subfamily of E3 ubiquitin ligases with approximately 80 members of this family, are widely distributed in mammalian cells. TRIMs actively participate in ubiquitination of target proteins, a type of post-translational modification associated with protein degradation and other functions. Tripartite motif-containing protein 29 (TRIM29), a member of the TRIM family, differs from other members of this family in that it lacks the RING finger structural domain containing cysteine and histidine residues that mediates DNA binding, protein-protein interactions, and ubiquitin ligase, at its N-terminus.
View Article and Find Full Text PDFTalanta
January 2025
Department of Chemistry, State University of Ponta Grossa, Ponta Grossa, CEP 84030-900, PR, Brazil. Electronic address:
The challenge of increasing food production while maintaining environmental sustainability can be addressed by using biofertilizers such as Azospirillum, which can enhance plant growth and colonize more than 100 plant species. The success of this biotechnology depends on the amount of plant growth-promoting bacteria associated with the plant during crop development. However, monitoring bacterial population dynamics after inoculation requires time-consuming, laborious, and costly procedures.
View Article and Find Full Text PDFBiomol NMR Assign
January 2025
Department of Chemistry and Chemical Biology, TU Dortmund University, Dortmund, Germany.
Cyclic GMP-AMP synthase (cGAS) is a DNA-sensing enzyme that is a member of the nucleotidyltransferase (NTase) family and functions as a DNA sensor. The protein is comprised of a catalytic NTase core domain and an unstructured hypervariable N-terminal domain (NTD) that was reported to increase protein activity by providing an additional DNA-binding surface. We report nearly complete H, N, and C backbone chemical-shift assignments of mouse cGAS NTD (residues 5-146), obtained with a set of 3D and 4D solution NMR experiments.
View Article and Find Full Text PDFMol Biol Rep
January 2025
Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, Queen Square House, London, WC1N 3BG, UK.
Background: Male EBP disorder with neurologic defects (MEND syndrome) is an extremely rare disorder with a prevalence of less than 1/1,000,000 individuals worldwide. It is inherited as an X-linked recessive disorder caused by impaired sterol biosynthesis due to nonmosaic hypomorphic EBP variants. MEND syndrome is characterized by variable clinical manifestations including intellectual disability, short stature, scoliosis, digital abnormalities, cataracts, and dermatologic abnormalities.
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