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Molecular adaptations to endurance exercise and skeletal muscle fibre plasticity
Published in Adam P. Sharples, James P. Morton, Henning Wackerhage, Molecular Exercise Physiology, 2022
As described above, each time a muscle contracts, intracellular calcium levels increase >100-fold. This means that whether a cardiac rehab patient exercises for 3 minutes, or 3 hours, their muscle will see a high Ca+2 concentration for the whole time. Therefore, Ca+2 is a likely signalling molecule to encode the duration of exercise (Figure 9.10). Calcium can influence the endurance phenotype through the ‘sensors’ called calcium-calmodulin-activated protein kinases (CaMKs). The primary CaMK in skeletal muscle is CaMKII. CaMKII is activated by exercise (60) and when over expressed in skeletal muscle CaMK can increase PGC-1α expression, and PGC-1α acts as the effector by increasing mitochondrial mass, enzymes for fat oxidation and fatigue resistance (61). These data suggest that exercise duration can be sensed through the repeated increase in Ca+2 activating CaMKII leading to an increase in PGC-1α2/3 and muscle endurance (Figure 9.10).
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
The calcium released with muscular contraction increases CaMKII activity, which induces GLUT4 translocation and consequently glucose uptake. CaMKII inhibitors can reduce glucose uptake in vitro following contractile activity (Erickson et al., 2011, 2008). Interestingly, CaMKII activity is increased by some oxidative modifications in the methionine pair 281/282, which are located in its regulatory domain (Erickson et al., 2011, 2008). This suggests that CAMKII could be an effector that links ROS and glucose uptake through post-translational modifications, but to the best of our knowledge no direct evidence about this mechanism are available (Figure 3.2).
Signalling Pathways in The Regulation of Cellular Responses to Exercise
Published in Peter M. Tiidus, Rebecca E. K. MacPherson, Paul J. LeBlanc, Andrea R. Josse, The Routledge Handbook on Biochemistry of Exercise, 2020
Anders Gudiksen, Stine Ringholm, Henriette Pilegaard
Activated CaM also leads to phosphorylation and activation of the calmodulin-dependent protein kinase (CaMK) of which CaMKII is the main isoform in human SkM (102). CaMKII consists of a number of intricately interacting subunits that can autophosphorylate each other, exhibiting a deciphering property that translates the given Ca2+ signal into subtle phases of graded kinase activity depending on the amplitude and frequency of the exercise-driven Ca2+ bursts (17, 24). CaMKII phosphorylates transcription factors such as cAMP response element-binding protein (CREB) and myocyte enhancer factor 2 (MEF2), as well as type II histone deacetylases (HDACs) turning on transcription of genes involved in glucose metabolism and mitochondrial biogenesis. CAMK has also been shown to regulate glucose transport (128, 134) as well as fatty acid uptake and oxidation (1, 98) in contracting mouse and rat SkM (Figure 8.2).
Roles of CaMKIIβ in the neurotoxicity induced by ropivacaine hydrochloride in dorsal root ganglion
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Xianjie Wen, Yiqun Li, Xingqing Liu, Can Sun, Jinbing Lin, Wenli Zhang, Yabin Wu, Xiaoping Wang
CaMKII is a multifunctional protease, which is widely distributed in nerve tissue [1–3]. It plays an important role in the pathophysiological process such as cerebral ischemic injury, oxidative stress, excitatory amino acid toxicity and calcium overload [4–6]. CaMKII can be divided into four subtypes: alpha, beta, gamma and delta (α,β,γ,δ). Previous studies have shown that the above four subtypes are expressed in dorsal root ganglion (DRG) neurons of rats [7,8]. Moreover, all those subtypes of CaMKII mRNA expression are up-regulated in DRG neurons treated with ropivacaine hydrochloride [7]. At the same time, knockdown of CaMK IIγmRNA can alleviate the DRG neurons injury induced by ropivacaine hydrochloride. On the contrary, up-regulating the expression of CaMK IIγ can aggravate the DRG injury. Those data suggest that CaMK IIγ is closely related to the nerve injury induced by ropivacaine hydrochloride [8].
DL-3-n-butylphthalide (NBP) ameliorates cognitive deficits and CaMKII-mediated long-term potentiation impairment in the hippocampus of diabetic db/db mice
Published in Neurological Research, 2019
Ming Gao, Suxiao Ji, Jie Li, Songyun Zhang
CaMKII is a major synaptic protein in mediating LTP in the hippocampus. The simplest explanation for LTP is as follows. Glutamate binds to postsynaptic AMPARs and NMDARs. Ligand binding causes the AMPARs to open, resulting in a depolarization. NMDARs can only open when a depolarization from AMPAR activation leads to repulsion of the Mg2+ cation near the pore, allowing the pore to pass current [32]. Calcium entry through NMDARs leads to the activation of calmodulin. Calmodulin activates CaMKII, which then translocates to the postsynaptic density [33], where it enhances AMPAR-mediated transmission by phosphorylating AMPAR subunits and increasing the number of AMPARs at the synapse [24,34,35]. And LTP is potentiated and maintained during the process. NR2B is an essential regulatory subunit of NMDAR.NR2B has a lower probability of opening but remains open longer after glutamate release [36,37], a phenomenon that is crucial for LTP formation. GluR1 is the most extensively studied subunit of AMPARs. In this study, the decreased mRNA and protein levels of CaMKII, NR2B, and GluR1 in db/db mice indicate T2DM may impair cognition at least partly through the LTP decline.
Inhibition of LPS-induced brain injury by NR2B antagonists through reducing assembly of NR2B–CaMKII–PSD95 signal module
Published in Immunopharmacology and Immunotoxicology, 2019
Yuanjian Song, Xiaofang Zhao, Di Wang, Yi Zheng, Chunxiao Dai, Mengyuan Guo, Li Qin, Xiangru Wen, Xiaoyan Zhou, Zhian Liu
CaMKII is a major component of the postsynaptic density (PSD). As a multifunctional serine/threonine protein kinase, it has multiple phosphorylation sites and is densely distributed in synapses in the hippocampus and cortex of the brain. CaMKII plays an important role in the pathogenesis of neuroinflammation and is involved in the regulation of learning and memory processes [13]. Study proved that NR2B, CaMKII, and PSD95 are important regulators that can regulate a variety of physiological and pathological processes in brain [14]. Previous researches showed that NR2B and CaMKII activity and PSD95 signal module are significantly enhanced in hippocampus induced by inflammation, then their downstream signaling pathway were activated, and ultimately hippocampal cell damage and apoptosis will occur [14,15]. JNKs, belonging to the MAPK family, play a more important role in the process of gene expression and the pathogenesis of AD. Aβ oligomers and LPS can up-regulate the activity of JNK signaling pathway. Activated JNK pathway leads to phosphorylation of APP and Tau. It is worth of our attention that JNK activation is closely related to the progression of inflammatory brain diseases [16,17].