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Exercise Redox Signalling
Published in James N. Cobley, Gareth W. Davison, Oxidative Eustress in Exercise Physiology, 2022
Ruy A. Louzada, Jessica Bouviere, Rodrigo S. Fortunato, Denise P. Carvalho
Redox-mediated signalling is a post-translational regulation of protein function that occurs principally through the modification of protein cysteine residues. Sulphhydryl groups on cysteines are the preferred targets for oxidation or for the formation of disulphide bonds. Therefore, it has been debated that redox-mediated signals are not likely a “switch on/off” mechanism. Instead, redox modification of the quaternary structure can change protein function by activating or inhibiting its enzymatic activity. Allosteric disulphides can also control protein function when they undergo redox change. Moreover, protein redox modifications can affect its lifetime, cellular location. To illustrate what occurs during muscle contraction, redox modification of calcium handling proteins and modulation of the sensitivity to Ca2+ are some examples of how exercise-induced ROS affect contractile function.
Regulation of Skeletal Muscle Reactive Oxygen Species During Exercise
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Catherine A. Bellissimo, Christopher G.R. Perry
A common assumption with in vitro and in situ ROS kinetics is that the measures are reflective of what must have occurred during exercise in vivo (in the body before the muscle was sampled). In this light, the effect of blood flow, circulating humoral factors, substrate supply (glucose vs. fat vs. anapleurosis), and stress signals generated inside the muscle fibres during exercise are typically not captured with in vitro assays. This fact poses both a challenge and an advantage, such that their absence might limit our understanding of how ROS is truly regulated in vivo but also allow us to detect how exercise alters the post-translational regulation of ROS-generating enzymes that are trapped after tissue sampling. Furthermore, while a change in ROS generation in vitro is thought to reflect the same change in vivo during exercise, a lack of change in vitro might represent a type II error (false negative), given the absence of physiological systems or contraction itself during most assays. As such, it is important that continued efforts are made to design in vitro experiments to capture in vivo regulatory mechanisms present in muscle during exercise.
Structure and Function of the Urokinase-Type Plasminogen Activator Gene
Published in Pia Glas-Greenwalt, Fibrinolysis in Disease Molecular and Hemovascular Aspects of Fibrinolysis, 2019
Yoshikuni Negamine, Janet S. Lee, Pierre-Alain Menoud, Rika Nanbu
Extracellular proteolysis is indispensable for various biological processes in multicellular organisms, e.g., in tissue remodeling during embryogenesis, wound healing and angiogenesis, gametogenesis, fibrinolysis, inflammation, and tumor metastasis. Urokinase-type plasminogen activator (u-PA) is a secreted protease that converts the zymogen plasminogen to plasmin, a trypsin-like serine protease with wide substrate specificity. Through the interaction with a specific u-PA receptor on the cell surface and subsequent generation of active plasmin, u-PA plays an important role in the processes mentioned above (see reviews1-8). Reflecting its wide range of biological activity, u-PA is expressed by a large number of cell types and its expression is controlled by a variety of extracellular signals depending on cell type. The multitude of positive and negative modulators of PA expression at various steps from gene transcription to enzyme activity results in numerous modes of regulation of final u-PA activity. As the post-translational regulation of u-PA expression is dealt with in several other chapters in this book, we will confine our discussion to the regulation of u-PA mRNA levels, i.e., to u-PA gene transcription and u-PA mRNA stability. However, the discussion is by no means exhaustive and focuses mainly on works carried out in our lab during the last few years.
Negative Regulation of RIG-I by Tim-3 Promotes H1N1 Infection
Published in Immunological Investigations, 2023
Qingzhu Shi, Ge Li, Shuaijie Dou, Lili Tang, Chunmei Hou, Zhiding Wang, Yang Gao, Zhenfang Gao, Ying Hao, Rongliang Mo, Beifen Shen, Renxi Wang, Yuxiang Li, Gencheng Han
Post-translational regulation, particularly ubiquitination, plays a critical role in the regulation of RIG-I activity (Wang et al. 2016). Reports have shown that K48-linked ubiquitination of RIG-I leads to RIG-I degradation by the proteasome (Chen et al. 2013; Oshiumi et al. 2012). To test whether Tim-3 regulates RIG-I ubiquitination, we transfected HEK-293T cells with Flag-tagged RIG-I and HA-tagged K48-Ub along with varying doses of plasmids expressing Tim-3 (Tim-3-WT) or plasmids expressing Y265F/Y272F of Tim-3 (Tim-3-Y/F), two residues that are indispensable for Tim-3 signaling (Tomkowicz et al. 2015), or Tim-3 lacking an intracellular tail (Tim-3-ΔIC). Our results show that Tim-3 signaling promoted RIG-I K48-linked ubiquitination in a dose-dependent manner (Figure 5e), which is responsible for RIG-I degradation. However, when Tim-3 265/272 tyrosine residues of the intracellular domain were replaced with phenylalanine or the intracellular domain was deleted, Tim-3-enhanced ubiquitination of RIG-I was significantly reversed (Figure 5e). Moreover, the Y/F mutants of Tim-3 (Y265F/Y272F) weakened the binding of Tim-3 with RIG-I, while deletion of the intracellular domain of Tim-3 (ΔIC) resulted in the loss of binding activity of Tim-3 with RIG-I. These data suggest that Tim-3 catalyzes K48-linked ubiquitination to promote the degradation of RIG-I, and that Tim-3 interacts with RIG-I through its intracellular domain, in which Y265/Y272 play an important role.
Regulation of flagellar motility and biosynthesis in enterohemorrhagic Escherichia coli O157:H7
Published in Gut Microbes, 2022
Hongmin Sun, Min Wang, Yutao Liu, Pan Wu, Ting Yao, Wen Yang, Qian Yang, Jun Yan, Bin Yang
In addition to transcriptional regulation, post-transcriptional and post-translational regulation play a key role in coordinating flagellar gene expression networks.72 Post-transcriptional regulation is highly versatile and adaptable; it controls RNA availability in cellular time and space.90 Messenger RNA stability, transport, storage, and translation are largely determined by the interaction of mRNA with post-transcriptional regulatory proteins and sRNAs.91,92 Post-translational regulation controls the biochemical alteration of proteins involving generally reversible covalent modification or irreversible processing to regulate their activity, location, or stability.93,94 Post-transcriptional and post-translational regulatory proteins known to regulate EHEC O157:H7 motility and flagellar biosynthesis include CsrA, ClpXP, and Hfq (Figure 6 and Table 1).
Engeletin ameliorates pulmonary fibrosis through endoplasmic reticulum stress depending on lnc949-mediated TGF-β1-Smad2/3 and JNK signalling pathways
Published in Pharmaceutical Biology, 2020
Jinjin Zhang, Xiaoqing Chen, Hongbin Chen, Rongrong Li, Pan Xu, Changjun Lv, Bo Liu, Xiaodong Song
The mitochondria and ER play a synergistic role in enhancing the post-translational regulation of proteins and modulating the 3D architecture and functions of chromatin (Ben-Sahra and Puissant 2018; Hernández-Alvarez et al. 2019). We did not explore mitochondrial regulation under engeletin treatment in the current work, but we previously reported that dysfunctional mitochondria have a decreased membrane potential and damage the electron transport chain; these aberrant conditions contribute to the fibrotic process (Gao et al. 2017). Most patients with IPF are older than 60 years; thus, IPF is an age-associated disease (Mora et al. 2017). López-Otín et al. (2013) proposed that pivotal hallmarks, including the shortening of telomeres and mitochondrial dysfunction, can occur simultaneously and interact with each other in aging diseases. However, the mechanistic link among these aging hallmarks is unclear.