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Muscle Cell Line (muscle + cell_line)
Selected Abstracts,-Dystroglycan is essential for the induction of Egr3, a transcription factor important in muscle spindle formationDEVELOPMENTAL NEUROBIOLOGY, Issue 7 2010Stacey Williams Abstract Muscle spindle fibers are specialized stretch receptors that allow the perception and coordination of limb movement. The differentiation of these specialized structures is initiated by signals derived from the in growing Ia sensory neurons during development. While the direct molecular signaling mechanisms between sensory neurons and developing muscle at nascent spindle fibers have been well documented in past studies the roles of muscle basal lamina components on this process have not previously been described. As such, our initial experiments addressed potential roles for agrin (AGRN) and laminin (LN) in the expression of the transcription factor Egr3. Levels of Egr3 were monitored using immunoblot analysis and both basal lamina molecules proved effective in inducing Erg3 expression. Previous work had established neuregulin (NRG) as a critical signaling component in spindle fiber development so blocking experiments with NRG and ErbB inhibitors were then used to determine if LN-induced Egr3 expression was occurring as a result of NRG-ErbB signaling and not via other, novel pathway. Inhibiting signaling through this pathway did indeed reduce the expression of Egr3. Finally, we looked at ,-dystrogylcan, a shared receptor for AGRN and LN at neuromuscular junctions. Using a ,-dystroglycan (,-DG) silenced muscle cell line and an anti-,-DG antibody we attempted to block basal lamina/,-DG interactions. Again, and in both instances, Egr3 expression was significantly decreased. Taken together, analysis of the results from these experiments revealed that indeed AGRN, LN, and ,-DG influence Egr3 levels and therefore may play an important role in spindle fiber differentiation. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70:498,507, 2010 [source] Nuclear and nuclear envelope localization of dystrophin Dp71 and dystrophin-associated proteins (DAPs) in the C2C12 muscle cells: DAPs nuclear localization is modulated during myogenesisJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2008R. González-Ramírez Abstract Dystrophin and dystrophin-associated proteins (DAPs) form a complex around the sarcolemma, which gives stability to the sarcolemma and leads signal transduction. Recently, the nuclear presence of dystrophin Dp71 and DAPs has been revealed in different non-muscle cell types, opening the possibility that these proteins could also be present in the nucleus of muscle cells. In this study, we analyzed by Immunofluorescence assays and Immunoblotting analysis of cell fractions the subcellular localization of Dp71 and DAPs in the C2C12 muscle cell line. We demonstrated the presence of Dp71, ,-sarcoglycan, ,-dystrobrevin, ,-dystroglycan and ,-syntrophin not only in plasma membrane but also in the nucleus of muscle cells. In addition, we found by Immunoprecipitation assays that these proteins form a nuclear complex. Interestingly, myogenesis modulates the presence and/or relative abundance of DAPs in the plasma membrane and nucleus as well as the composition of the nuclear complex. Finally, we demonstrated the presence of Dp71, ,-sarcoglycan, ,-dystroglycan, ,-dystrobrevin and ,-syntrophin in the C2C12 nuclear envelope fraction. Interestingly, ,-sarcoglycan and ,-dystroglycan proteins showed enrichment in the nuclear envelope, compared with the nuclear fraction, suggesting that they could function as inner nuclear membrane proteins underlying the secondary association of Dp71 and the remaining DAPs to the nuclear envelope. Nuclear envelope localization of Dp71 and DAPs might be involved in the nuclear envelope-associated functions, such as nuclear structure and modulation of nuclear processes. J. Cell. Biochem. 105: 735,745, 2008. © 2008 Wiley-Liss, Inc. [source] Cortisol and IGF-1 synergistically up-regulate taurine transport by the rat skeletal muscle cell line, L6BIOFACTORS, Issue 1-4 2004Sung-Hee Park Abstract This study was undertaken to evaluate effects of exercise-induced hormones, cortisol, IGF-1, and ,-endorphin, on the regulation of taurine transport activity in rat skeletal myoblasts, L6 cells. Challenge of L6 cells with cortisol (100 nM) for 24 hrs resulted in a 165% increase in taurine transport activity, 220% increase in Vmax of the taurine transporter, and 55% increase in taurine transporter/ ,-actin mRNA level compared with untreated control cells. Neither IGF-1 (1,100 nM) nor ,-endorphin (1,20 nM), added in the incubation medium separately for 24 hrs, affected taurine uptake by L6 cells. However, when cells were co-treated with IGF-1 (10 nM) plus cortisol (100,nM), taurine transport activity (37% increase, p < 0.05), Vmax of the transporter (54%, p < 0.05), and taurine transporter/ ,-actin mRNA level were further increased compared to the value for cells treated with cortisol alone. These results suggest that taurine transport by skeletal muscle cells appear to be synergistically up-regulated during a prolonged exercise via elevated levels of cortisol and IGF-1 in muscle. [source] Characterization of Bves expression during mouse development using newly generated immunoreagentsDEVELOPMENTAL DYNAMICS, Issue 6 2006Travis K. Smith Abstract Bves (blood vessel/epicardial substance) is a transmembrane protein postulated to play a role in cell,cell interaction/adhesion. It was independently isolated by two groups as a gene product highly enriched in the developing heart. Disagreement exists about its expression during development. Most notably, the expression of Bves in non-muscle cells is disputed. Determining the expression profile of Bves is a critical initial step preceding the characterization of protein function in development and in the adult. We have generated new monoclonal antibodies against mouse Bves and used these immunoreagents to elucidate Bves expression in development. As expected, we detect Bves in myocytes of the developing heart throughout development. In addition, skeletal and smooth muscle cells including those of the coronary system express Bves. Finally, specific, but not all, epithelial derivatives of the three germ layers are stained positively with these monoclonal antibodies. Protein expression in cultured epithelial and muscle cell lines corroborate our in vivo findings. Taken together, these results demonstrate the expression of Bves in a wide range of epithelial and muscle cells during mouse embryogenesis and indicate a broad function for this protein in development, and show that these newly generated reagents will be invaluable in further investigation of Bves. Developmental Dynamics 235:1701,1708, 2006. © 2006 Wiley-Liss, Inc. [source] Neuregulin-1 induces acetylcholine receptor transcription in the absence of GABP, phosphorylationJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2008Carter A. Herndon Abstract Localization of acetylcholine receptors (AChRs) to the postsynaptic region of muscle is mediated in part by transcriptional mechanisms, because the genes encoding AChR subunits are transcribed selectively in synaptic myofiber nuclei. Neuregulin-1 (NRG-1) is a synaptic signal and induces transcription of AChRs in muscle cells. Signaling by NRG-1 is thought to involve the transcription factor GA-binding protein (GABP), a heterodimer of GABP,, which is a member of the Ets family, and GABP,. Phosphorylation of certain other Ets proteins outside the Ets DNA-binding domain serves to stimulate transcriptional activation in response to extracellular signals. According to previous studies, NRG-1 stimulates phosphorylation of GABP, at threonine 280 in the N-terminal region adjacent to the Ets domain, suggesting that GABP, phosphorylation might contribute to NRG-1 responsiveness. To determine the functional importance of the N-terminal region of GABP, and whether its function is regulated by phosphorylation, we generated muscle cell lines in which the endogenous GABP, gene was deleted and replaced by variants of GABP, mutated in the N-terminal region. We found that NRG-1 can induce transcription in cells with mutated T280 phosphorylation site, indicating that T280 phosphorylation does not contribute to NRG-1 responsiveness. We also found that NRG-1-induced transcription occurs in cells missing the entire N-terminal region of GABP,. Because NRG-1 signaling is not expected to alter the function of the C-terminal region, which remains in these cells, these results suggest that GABP,, or other interacting components, rather than GABP, directly, is targeted by NRG-1 signaling. © 2007 Wiley-Liss, Inc. [source] | ||||||||||