Histone demethylase LSD1 (also known as KDM1 and AOF2) is active in various cancer cells, but its biological significance in human carcinogenesis is unexplored. In this study, we explored hypothesized interactions between LSD1 and MYPT1, a known regulator of RB1 phosphorylation. We found that MYPT1 was methylated in vitro and in vivo by histone lysine methyltransferase SETD7 and demethylated by LSD1, identifying Lys 442 of MYPT1 as a target for methylation/demethylation by these enzymes. LSD1 silencing increased MYPT1 protein levels, decreasing the steady state level of phosphorylated RB1 (Ser 807/811) and reducing E2F activity. MYPT1 methylation status influenced the affinity of MYPT1 for the ubiquitin-proteasome pathway of protein turnover. MYPT1 was unstable in murine cells deficient in SETD7, supporting the concept that MYPT1 protein stability is physiologically regulated by methylation status. LSD1 overexpression could activate RB1 phosphorylation by inducing a destabilization of MYPT1 protein. Taken together, our results comprise a novel cell cycle regulatory mechanism mediated by methylation/demethylation dynamics, and they reveal the significance of LSD1 overexpression in human carcinogenesis.
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http://dx.doi.org/10.1158/0008-5472.CAN-10-2446 | DOI Listing |
J Biol Chem
December 2024
Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Hungary. Electronic address:
Dysregulation of the expression levels and the activity of kinases/phosphatases is an intrinsic hallmark of tumor transformation and progression, as either as a primary cause or consequence. The myosin phosphatase (MP)/protein arginine methyltransferase 5 (PRMT5)/histone (H4) pathway is an oncogenic signaling pathway downregulating the gene expression of tumor suppressors. However, the upstream regulators of the pathway are unknown.
View Article and Find Full Text PDFZhongguo Zhong Yao Za Zhi
September 2024
Key Laboratory of Traditional Chinese Medicine for Prevention and Control of Regional High Incidence Diseases in Ningxia,Ministry of Education, Ningxia Medical University Yinchuan 750004, China.
Based on transcriptomics technology, this study investigated the molecular mechanisms of Xiangsha Liujunzi Decoction in treating chronic atrophic gastritis(CAG), which were confirmed through experimental validation. The CAG rat model was built by the MNNG composite multi-factor method, followed by a 90-day administration of Xiangsha Liujunzi Decoction. The study measured the rat body mass and 3-hour food intake in each group and observed the pathological changes in gastric tissue using HE staining.
View Article and Find Full Text PDFEur J Pharmacol
January 2025
Institute of Physiology, Brandenburg Medical School Theodor Fontane, Germany; Research Cluster, Molecular Mechanisms of Cardiovascular Diseases, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany.
The femoral artery (FA) is the largest vessel in the hindlimb circulation and its proper tone regulation ensures adequate blood supply to muscle tissue. We investigated whether an alanine mutation of the targeting subunit of myosin-light-chain-phosphatase (MLCP), MYPT1, at threonine 696 (MYPT1-T696A/+), decisive for enzyme acivity, affects the responsiveness of young and old FAs (y-FAs and o-FAs) to activation of nitric-oxide/soluble-guanylate-cyclase/protein-kinase-G cascade (NO/sGC/PKG). Contractile responses of the vessels were measured by wire myography.
View Article and Find Full Text PDFJ Control Release
October 2023
Department of Life Sciences, Centre for Therapeutic Innovation, University of Bath, Bath BA2 7AY, UK. Electronic address:
The intestinal paracellular route of absorption is modulated via tight junction (TJ) structures located at the apical neck of polarized intestinal epithelial cells to restrict solute movement through the intercellular space between them. Tight junctions open or close in response to changes in the phosphorylation status of light chain (MLC) at position Ser-19. This phosphorylation event is primarily controlled by MLC kinase (MLCK) and MLC phosphatase (MLCP), the latter being a holoenzyme that involves interaction between protein phosphatase 1 (PP1) and myosin targeting protein 1 (MYPT1).
View Article and Find Full Text PDFAm J Respir Cell Mol Biol
October 2024
Rutgers Institute for Translational Medicine and Science, New Brunswick, New Jersey, United States;
Leucine-rich repeat containing 8A (LRRC8A) is an obligatory constituent of the volume-regulated anion channel (VRAC) that is fundamental to a wide range of biological processes, including regulating cell size, proliferation, and migration. Here we explored the physiological role for VRAC in excitation-contraction (E-C) coupling and shortening of human airway smooth muscle (HASM). In HASM cells, pharmacological inhibition of VRAC with DCPIB (0.
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