Smad7 functions as an intracellular antagonist in transforming growth factor-beta (TGF-beta) signaling. In addition to interacting stably with the activated TGF-beta type I receptor (TbetaRI) to prevent phosphorylation of the receptor-regulated Smads (Smad2 and Smad3), Smad7 also induces degradation of the activated TbetaRI through association with different E3 ubiquitin ligases. Using the two-hybrid screen, we identified atrophin 1-interacting protein 4 (AIP4) as an E3 ubiquitin ligase that specifically targets Smad7 for ubiquitin-dependent degradation without affecting the turnover of the activated TbetaRI. Surprisingly, we found that despite the ability to degrade Smad7, AIP4 can inhibit TGF-beta signaling, presumably by enhancing the association of Smad7 with the activated TbetaRI. Consistent with this notion, expression of a catalytic mutant of AIP4, which is unable to induce ubiquitination and degradation of Smad7, also stabilizes the TbetaRI.Smad7 complex, resulting in inhibition of TGF-beta signaling. The ability of AIP4 to enhance the inhibitory function of Smad7 independent of its ubiquitin ligase activity reveals a new mechanism by which E3 ubiquitin ligases may function to turn off TGF-beta signaling.
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http://dx.doi.org/10.1074/jbc.M500188200 | DOI Listing |
iScience
January 2025
Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA.
Maintaining metabolic homeostasis requires coordinated nutrient utilization between intracellular organelles and across multiple organ systems. Many organs rely heavily on mitochondria to generate (ATP) from glucose, or stored glycogen. Proteins required for ATP generation are encoded in both nuclear and mitochondrial DNA (mtDNA).
View Article and Find Full Text PDFBiochem Pharmacol
January 2025
Department of Dermatology, Qilu Hospital Shandong University Jinan Shandong China. Electronic address:
Immune cell infiltration and keratinocyte (KC) hyperproliferation are characteristics of psoriasis. Radical S-adenosyl methionine domain-containing 2 (RSAD2) plays an integral role in the innate immune response and is associated with various immune-related diseases. However, RSAD2's expression and role in modulating immune responses in psoriasis remain unexplored.
View Article and Find Full Text PDFJ Ethnopharmacol
January 2025
Department of Spleen and Gastroenterology, Dongzhimen Hospital, Beijing University of Chinese Medicine,100007; Liver Diseases Academy of Traditional Chinese Medicine, Beijing University of Chinese Medicine,100029.
Ethnopharmacological Relevance: Traditional Chinese Medicine (TCM), as a longstanding therapeutic approach, offers unique advantages and potential in the treatment of liver cancer. Recent studies have highlighted its role in preventing liver cancer progression by modulating key signaling pathways. TCM's multi-component, multi-target, and multi-pathway mechanisms of action have garnered significant attention in the medical community for their ability to address complex diseases like liver cancer.
View Article and Find Full Text PDFFront Immunol
January 2025
Department of Neurological Care Unit, The First Affiliated Hospital of YangTze University, Jingzhou, Hubei, China.
Background: Recent years have seen persistently poor prognoses for glioma patients. Therefore, exploring the molecular subtyping of gliomas, identifying novel prognostic biomarkers, and understanding the characteristics of their immune microenvironments are crucial for improving treatment strategies and patient outcomes.
Methods: We integrated glioma datasets from multiple sources, employing Non-negative Matrix Factorization (NMF) to cluster samples and filter for differentially expressed metabolic genes.
Front Neurosci
January 2025
Department of Physical Therapy, China Medical University, Taichung, Taiwan.
Introduction: Parkinson's disease (PD) is characterized by progressive neurodegeneration within the nigrostriatum, leading to motor dysfunction. This systematic review aimed to summarize the effects of various exercise training regimens on protein or gene expression within the nigrostriatum and their role in neuroprotection and motor function improvement in animal models of Parkinson's disease (PD).
Methods: PubMed, EMBASE, and Web of Science were searched up to June 2024 and included sixteen studies that adhere to PRISMA guidelines and CAMARADES checklist scores ranging from 4 to 6 out of 10.
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