Expression and functional properties of four slow skeletal troponin T isoforms in rat muscles

Kischel, Philippe; Bastide, Bruno; Müller, Marc; Dubail, F.; Offredi, F; Jin, Jian‐Ping; Mounier, Yvonne; Martial, Joseph

doi:10.1152/ajpcell.00365.2004

Cited by 14 publications

(8 citation statements)

References 34 publications

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“…However, our immunoblot analysis demonstrate that the slow skinned fibers used in functional experiments expressed only slow isoforms of regulatory proteins as previously reported [34], [35]. Thus, only the increase in slow MLC2 O-GlcNAcylation might be related to the modifications in calcium activation properties observed in hyperglycosylated fibers.…”

Section: Discussionsupporting

confidence: 78%

“…Concerning TnT, there are several isoforms presenting a molecular weight from 31 to 36 kDa. In whole protein extract, three slow isoforms (panel B) are resolved and assigned as previously described [34], [35]. In the fraction of proteins retained by RL-2 antibody (lane 2), the sTnT1 was clearly revealed, as well as sTnT2, while no signal was detected for sTnT3.…”

Section: Resultsmentioning

confidence: 95%

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Increasing O-GlcNAcylation Level on Organ Culture of Soleus Modulates the Calcium Activation Parameters of Muscle Fibers

et al. 2012

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O-N-acetylglucosaminylation is a reversible post-translational modification which presents a dynamic and highly regulated interplay with phosphorylation. New insights suggest that O-GlcNAcylation might be involved in striated muscle physiology, in particular in contractile properties such as the calcium activation parameters. By the inhibition of O-GlcNAcase, we investigated the effect of the increase of soleus O-GlcNAcylation level on the contractile properties by establishing T/pCa relationships. We increased the O-GlcNAcylation level on soleus biopsies performing an organ culture of soleus treated or not with PUGNAc or Thiamet-G, two O-GlcNAcase inhibitors. The enhancement of O-GlcNAcylation pattern was associated with an increase of calcium affinity on slow soleus skinned fibers. Analysis of the glycoproteins pattern showed that this effect is solely due to O-GlcNAcylation of proteins extracted from skinned biopsies. We also characterized the O-GlcNAcylated contractile proteins using a proteomic approach, and identified among others troponin T and I as being O-GlcNAc modified. We quantified the variation of O-GlcNAc level on all these identified proteins, and showed that several regulatory contractile proteins, predominantly fast isoforms, presented a drastic increase in their O-GlcNAc level. Since the only slow isoform of contractile protein presenting an increase of O-GlcNAc level was MLC2, the effect of enhanced O-GlcNAcylation pattern on calcium activation parameters could involve the O-GlcNAcylation of sMLC2, without excluding that an unidentified O-GlcNAc proteins, such as TnC, could be potentially involved in this mechanism. All these data strongly linked O-GlcNAcylation to the modulation of contractile activity of skeletal muscle.

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Section: Discussionsupporting

confidence: 78%

Section: Resultsmentioning

confidence: 95%

Increasing O-GlcNAcylation Level on Organ Culture of Soleus Modulates the Calcium Activation Parameters of Muscle Fibers

et al. 2012

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“…In rat, rabbit, and human muscles, two isoforms (TnT1s and TnT2s) have been identified in slow fibers (249,691,716). Three slow splicing variants (sTnT1, sTnT2, and sTnT3) were described in mouse muscles, and a new variant, with a molecular weight slightly higher than that of sTnT3, was found in rat muscles (414).…”

Section: Response Of Myofibrils To Calciummentioning

confidence: 99%

Fiber Types in Mammalian Skeletal Muscles

Schiaffino

Reggiani

2011

Physiological Reviews

2,246

2,465

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Mammalian skeletal muscle comprises different fiber types, whose identity is first established during embryonic development by intrinsic myogenic control mechanisms and is later modulated by neural and hormonal factors. The relative proportion of the different fiber types varies strikingly between species, and in humans shows significant variability between individuals. Myosin heavy chain isoforms, whose complete inventory and expression pattern are now available, provide a useful marker for fiber types, both for the four major forms present in trunk and limb muscles and the minor forms present in head and neck muscles. However, muscle fiber diversity involves all functional muscle cell compartments, including membrane excitation, excitation-contraction coupling, contractile machinery, cytoskeleton scaffold, and energy supply systems. Variations within each compartment are limited by the need of matching fiber type properties between different compartments. Nerve activity is a major control mechanism of the fiber type profile, and multiple signaling pathways are implicated in activity-dependent changes of muscle fibers. The characterization of these pathways is raising increasing interest in clinical medicine, given the potentially beneficial effects of muscle fiber type switching in the prevention and treatment of metabolic diseases.

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“…Differently expressed isoforms of proteins are the basis of muscle heterogeneity inherent to soleus and gastrocnemius muscles [10,15,[25][26][27]]. In the current study, this was shown by the variation in the relative abundances of MLC isoforms and metabolic enzymes as well as in the presence of parvalbumin in the white portion of gastrocnemius muscle [28].…”

Section: Discussionmentioning

confidence: 54%

Subcellular proteomics of mice gastrocnemius and soleus muscles

Vitorino

Ferreira

Neuparth

et al. 2007

Analytical Biochemistry

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A proteomics characterization of mice soleus and gastrocnemius white portion skeletal muscles was performed using nuclear, mitochondrial/membrane, and cytosolic subcellular fractions. The proposed methodology allowed the elimination of the cytoskeleton proteins from the cytosolic fraction and of basic proteins from the nuclear fraction. The subsequent protein separation by twodimensional gel electrophoresis prior to mass spectrometry analysis allowed the detection of more than 600 spots in each muscle. In the gastrocnemius muscle fractions, it was possible to identify 178 protein spots corresponding to 108 different proteins. In the soleus muscle fractions, 103 different proteins were identified from 253 positive spot identifications. A bulk of cytoskeleton proteins such as actin, myosin light chains, and troponin were identified in the nuclear fraction, whereas mainly metabolic enzymes were detected in the cytosolic fraction. Transcription factors and proteins associated with protein biosynthesis were identified in skeletal muscles for the first time by proteomics. In addition, proteins involved in the mitochondrial redox system, as well as stress proteins, were identified. Results confirm the potential of this methodology to study the differential expressions of contractile proteins and metabolic enzymes, essential for generating functional diversity of muscles and muscle fiber types. Keywords Skeletal muscle; Subcellular fractionation; ProteomicsHuman skeletal muscle is very heterogeneous in composition, being constituted by different types of muscle fibers showing significant differences in their contractile speed and metabolic profile that result from specific protein expression [1][2][3][4]. In rodents, especially mice and rats, muscle fibers present a more uniform distribution among the different muscles, allowing the use of the entire muscles to study specific phenotypes. In this regard, the soleus and the white portion of gastrocnemius of mice are composed mainly of fast-and slow-twitch muscle fibers, respectively [5][6][7], and these two muscles have been used as typical models in proteomics. During the past few years, several studies have been performed using two-dimensional gel electrophoresis (2-DE) 1 combined with mass spectrometry (MS) to characterize skeletal muscle protein composition of typical slow-and fast-twitch skeletal muscles [8][9][10][11][12][13][14][15][16][17]. In a recent proteomics study on murine gastrocnemius and soleus muscle extracts, performed by Gelfi and coworkers [9], more than 800 spots on each 2-DE were detected by silver staining, leading to the identification of 85 different proteins belonging to the most abundant structural and metabolic protein classes. Despite the large number of visualized spots by 2-DE, proteins with lower relative abundances, usually involved in protein biosynthesis and cell stress response, are probably masked by structural or metabolic proteins [18,19]. To counteract this, Jarrold and coworkers [14] performed the depletion of abundant mus...

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Expression and functional properties of four slow skeletal troponin T isoforms in rat muscles

Cited by 14 publications

References 34 publications

Increasing O-GlcNAcylation Level on Organ Culture of Soleus Modulates the Calcium Activation Parameters of Muscle Fibers

Increasing O-GlcNAcylation Level on Organ Culture of Soleus Modulates the Calcium Activation Parameters of Muscle Fibers

Fiber Types in Mammalian Skeletal Muscles

Subcellular proteomics of mice gastrocnemius and soleus muscles

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