Cytoskeletal structure of skeletal muscle: identification of an intricate exosarcomeric microtubule lattice in slow- and fast-twitch muscle fibers.

Boudriau, Sophie; Vincent, Michel; Côté, Claude H.; Rogers, Peter A. W.

doi:10.1177/41.7.8515044

Cited by 36 publications

(27 citation statements)

References 32 publications

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“…The surface layer of microtubules in SOL fibers has been observed by others (Boudriau et al, 1993), as has the orthogonal pattern of microtubules in fast fibers (Rahkila et al, 1997). Similarly, pericentrin changed more completely in the EDL than in the SOL.…”

Section: Discussionmentioning

confidence: 61%

Golgi Complex, Endoplasmic Reticulum Exit Sites, and Microtubules in Skeletal Muscle Fibers Are Organized by Patterned Activity

Ralston

Ploug²,

Kalhovde

et al. 2001

J. Neurosci.

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The Golgi complex of skeletal muscle fibers is made of thousands of dispersed elements. The distributions of these elements and of the microtubules they associate with differ in fast compared with slow and in innervated compared with denervated fibers. To investigate the role of muscle impulse activity, we denervated fast extensor digitorum longus (EDL) and slow soleus (SOL) muscles of adult rats and stimulated them directly with patterns that resemble the impulse patterns of normal fast EDL (25 pulses at 150 Hz every 15 min) and slow SOL (200 pulses at 20 Hz every 30 sec) motor units. After 2 weeks of denervation plus stimulation, peripheral and central regions of muscle fibers were examined by immunofluorescence microscopy with regard to density and distribution of Golgi complex, microtubules, glucose transporter GLUT4, centrosomes, and endoplasmic reticulum exit sites. In extrajunctional regions, fast pattern stimulation preserved normal fast characteristics of all markers in EDL type IIB/IIX fibers, although inducing changes toward the fast phenotype in originally slow type I SOL fibers, such as a 1.5-fold decrease of the density of Golgi elements at the fiber surface. Slow pattern stimulation had converse effects such as a 2.2-fold increase of the density of Golgi elements at the EDL fiber surface. In junctional regions, where fast and slow fibers are similar, both stimulation patterns prevented a denervation-induced accumulation of GLUT4. The results indicate that patterns of muscle impulse activity, as normally imposed by motor neurons, play a major role in regulating the organization of Golgi complex and related proteins in the extrajunctional region of muscle fibers.

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Section: Discussionmentioning

confidence: 61%

Golgi Complex, Endoplasmic Reticulum Exit Sites, and Microtubules in Skeletal Muscle Fibers Are Organized by Patterned Activity

Ralston

Ploug²,

Kalhovde

et al. 2001

J. Neurosci.

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“…In contrast, DHPR is transported through the Golgi elements to transverse tubules, and in myofibers a majority of the Golgi elements are located beneath the sarcolemma (Lu et al 2001). Furthermore, microtubules that act as tracks for vesicular trafficking in mononucleated cells are dense in the subsarcolemmal region of myofibers (Boudriau et al 1993). These findings, together with the idea that transcripts of ER-translocated proteins reside beneath the sarcolemma, suggest that membrane protein synthesis, as well as exocytic trafficking, is restricted beneath the sarcolemma in skeletal myofibers.…”

Section: Discussionmentioning

confidence: 99%

Restricted Distribution of mRNAs Encoding a Sarcoplasmic Reticulum or Transverse Tubule Protein in Skeletal Myofibers

Nissinen

Kaisto

Salmela

et al. 2005

J Histochem Cytochem.

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S U M M A R Y Calsequestrin (CSQ) and dihydropyridine receptor (DHPR) are muscle cell proteins that are directed into the endoplasmic reticulum (ER) during translation. The former is subsequently found in the sarcoplasmic reticulum (SR) and the latter in the transverse tubule membrane. To elucidate the potential role of mRNA targeting within muscle cells, we have analyzed the localization of CSQ and DHPR proteins and mRNAs in primary cultured rat myotubes, in skeletal muscle cryosections, and in isolated flexor digitorum brevis muscle fibers. In the myotube stage of differentiation, the mRNAs distributed throughout the cell, mimicking the distribution of the endogenous ER marker proteins. In the adult skeletal myofibers, however, both CSQ and DHPR ␣ 1 transcripts located perinuclearly and in cross-striations flanking Z lines beneath the sarcolemma, a distribution pattern that sharply contrasted the interfibrillar distribution of typical ER proteins. Interestingly, all nuclei of the myofibers were transcriptionally active. In summary, the mRNAs encoding either a resident SR protein or a transverse tubule protein were located beneath the sarcolemma, implying that translocation of the respective proteins to the lumen of ER takes place at this location.

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“…However, the cytoskeletal organizations in skeletal muscle fibers and hepatocytes differ, especially concerning F-actin and microtubules. In skeletal muscle fibers, repeated assemblies of the actin-and myosin-based contractile units of myofibrils dominate the sarcoplasm, and microtubules are present mostly longitudinally between myofibrils and beneath the sarcolemma and transversely in a lattice-like arrangement (Parysek et al 1984;Kano et al 1991;Boudriau et al 1993). In hepatocytes, actin microfilaments are present throughout the cytoplasm, particularly beneath the plasma membranes around the bile canaliculi with a contractile function (Katsuma et al 1988;Watanabe et al 1991;Blankson et al 1995).…”

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confidence: 99%

Effects of Tissue Protectants on the Kinetics of Lactate Dehydrogenase in Cells

Nakae

Stoward

1997

J Histochem Cytochem.

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SUMMARYWe studied the effects of two tissue protectants, polyvinyl alcohol (PVA) and agarose gel, on a kinetic parameter of lactate dehydrogenase LDH that is assumed to be related to the extent of diffusion of the enzyme out of tissue sections during its histochemical assay. The kinetics of the enzyme in mouse gastrocnemius (skeletal) muscle fibers and periportal hepatocytes were determined in unfixed sections incubated either on substrate ( L -lactate)-containing agarose gel films or in aqueous assay media in the presence or absence of 18% PVA. The absorbances of the formazan final reaction products at their isobestic point were measured continuously in the cytoplasm of individual cells as a function of incubation time, using a real-time image analysis system. Whichever incubation medium was used, the absorbances in the two cell types increased nonlinearly during the first minute of incubation but linearly for incubation times between 1 and 3 min. The nonlinearity of the LDH reaction was analyzed using the equation v i Ϫ v ϭ a Њ A , where v i is the observed initial velocity determined from the absorbance changes during the first 10 sec of incubation and v and Њ A are respectively the gradient and intercept on the absorbance axis of the linear regression line of the absorbance on incubation times between 1 and 3 min. The plots of the observed ( v i Ϫ v ) against Њ A were linear. Their gradients a were characteristic for each cell type and tissue protectant. The a values for skeletal muscle fibers were 12-43% lower than those for hepatocytes. The a value for hepatocytes obtained with the PVA method was 32% lower than that determined with the gel film method. For skeletal muscle fibers, the a values determined by the two methods were almost the same. Addition of excess pyruvate to the aqueous assay medium had no effects on a for either muscle fibers or hepatocytes. In contrast, a was zero for sections of polyacrylamide gels containing purified enzyme, whether incubated on agarose films or in PVA media. These data confirmed that the constant a is related to the extent to which the enzyme diffuses out of sections during incubation but not to product inhibition of LDH by pyruvate. PVA was more effective for protecting diffusion of LDH from hepatocytes than from skeletal muscle fibers, possibly because hepatocytes contain a greater proportion of diffusable (unbound) LDH than skeletal muscle fibers.

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Cytoskeletal structure of skeletal muscle: identification of an intricate exosarcomeric microtubule lattice in slow- and fast-twitch muscle fibers.

Cited by 36 publications

References 32 publications

Golgi Complex, Endoplasmic Reticulum Exit Sites, and Microtubules in Skeletal Muscle Fibers Are Organized by Patterned Activity

Golgi Complex, Endoplasmic Reticulum Exit Sites, and Microtubules in Skeletal Muscle Fibers Are Organized by Patterned Activity

Restricted Distribution of mRNAs Encoding a Sarcoplasmic Reticulum or Transverse Tubule Protein in Skeletal Myofibers

Effects of Tissue Protectants on the Kinetics of Lactate Dehydrogenase in Cells

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