Actin has important functions in both cytoplasm and nucleus of the cell, with active nuclear transport mechanisms maintaining the cellular actin balance. Nuclear actin levels are subject to regulation during many cellular processes from cell differentiation to cancer. Here we show that nuclear actin levels increase upon differentiation of PC6.3 cells towards neuron-like cells. Photobleaching experiments demonstrate that this increase is due to decreased nuclear export of actin during cell differentiation. Increased nuclear actin levels lead to decreased nuclear localization of MRTF-A, a well-established transcription cofactor of SRF. In line with MRTF-A localization, transcriptomics analysis reveals that MRTF/SRF target gene expression is first transiently activated, but then substantially downregulated during PC6.3 cell differentiation. This study therefore describes a novel cellular context, where regulation of nuclear actin is utilized to tune MRTF/SRF target gene expression during cell differentiation.
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http://dx.doi.org/10.1016/j.yexcr.2022.113356 | DOI Listing |
iScience
January 2025
Department of Molecular Biology, University of Wyoming, Laramie, WY 82071, USA.
Cancers and neurodegenerative disorders are associated with both disrupted proteostasis and altered nuclear morphology. Determining if changes in nuclear morphology contribute to pathology requires an understanding of the underlying mechanisms, which are difficult to elucidate in cells where pleiotropic effects of altering proteostasis might indirectly influence nuclear morphology. To investigate direct effects, we studied nuclei assembled in egg extract where potentially confounding effects of transcription, translation, cell cycle progression, and actin dynamics are absent.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
December 2024
Key Laboratory of Orthopedics & Traumatology of Traditional Chinese Medicine and Rehabilitation, Ministry of Education Fuzhou 350122, China.
This study aims to explore the mechanism of Zhuanggu Jianxi Decoction in reducing synovial tissue inflammation in human knee osteoarthritis(KOA) via the liver X receptors(LXRs)/nuclear factor(NF)-κB signaling pathway. The synovial tissue samples were collected from 5 healthy volunteers and 30 KOA synovitis patients and cultured in vitro. The samples from the heathy volunteers were set as the normal group, and those from KOA synovitis patients were randomized into synovitis, Zhuanggu Jianxi Decoction, LXRα inhibitor, and N-CoR inhibitor groups.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
December 2024
Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences Beijing 100700, China.
This study aimed to investigate the potential role of Colquhounia Root Tablets against bone destruction in rheumatoid arthritis(RA) and its molecular mechanism. The study used ultra-performance liquid chromatography-mass spectrometry to analyze the major components of Colquhounia Root Tablets and predicted its candidate target gene set based on the major components. The key targets of RA bone destruction were obtained through GeneCards and the Database of Genetics and Medical Literature(OMIM), protein-protein interaction(PPI) network was constructed, and the key targets were identified by topological analysis.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Computer and Information Sciences, Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716, United States.
Liquid phase-separating proteins can form condensates that play an important role in spatial and temporal organization of biological cells. The understanding of the mechanisms that lead to the formation of protein condensates and their interactions with other biomolecules may lead to processing routes for soft materials with tailored geometry and function. Fused in sarcoma (FUS) is an example of a nuclear protein that forms stable complexes, and recent studies have highlighted its ability to wet actin filaments and bundle them into networks.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
State Key Laboratory of Wheat Improvement, College of Life Science, Shandong Agricultural University, Tai'an 271018, China.
In many plants, the asymmetric division of the zygote sets up the apical-basal body axis. In the cress , the zygote coexpresses regulators of the apical and basal embryo lineages, the transcription factors WOX2 and WRKY2/WOX8, respectively. WRKY2/WOX8 activity promotes nuclear migration, cellular polarity, and mitotic asymmetry of the zygote, which are hallmarks of axis formation in many plant species.
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