Involvement of Hexose transport in myogenic differentiation

Kudo, P. A.; Lo, Theodore C. Y.

doi:10.1002/jcp.1041450221

Cited by 8 publications

(25 citation statements)

References 44 publications

(41 reference statements)

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“…Cell culture. Rat L6 myoblasts were originally isolated by Yaffe [30]; clones D2, D9, and D23 are independent GLUT 3-mutants isolated from L6 cells [11][12][13][14]24]. Clones L6/G3A, L6/G3S, and L6/CMV are stable transfectants harbouring the GLUT3 antisense cDNA, GLUT3 sense cDNA, and the pRc/CMV vector (Invitrogen), respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Fusion index determination. Fusion index was used to determine the extent of myotube formation [ 13]. Five fields (at least 100 nuclei per field) per well were chosen to determine the extent of fusion.…”

Section: Methodsmentioning

confidence: 99%

“…different metabolic and developmental regulations. The rat skeletal L6 myoblast glucose transport system has been examined through a combination of biochemical, genetic and molecular biological approaches [1, 13,[19][20][21][22][23][24][25][26][27]. Studies with several independent spontaneous GLUT-mutants revealed that the GLUT 1, 3 and 4 genes were responsible for rat myoblast glucose transport processes [ 1,27].…”

Section: Introductionmentioning

confidence: 99%

“…Recent attempts in studying the physiological roles of the rat myoblast GLUT 3 transporter revealed a close correlation between GLUT 3 expression and the cells' myogenic ability. First, all independently isolated rat skeletal GLUT 3-myoblast mutants examined are impaired in myogenesis [1,13]. Furthermore, rat cardiac GLUT 3-myoblast mutants are also defective in myogenesis [28].…”

Section: Introductionmentioning

confidence: 99%

“…Our data suggest that GLUT 3 may regulate myogenesis by modulating the levels of signal transducers required for expression of myogenin and muscle-specific contractile protein genes.The in vitro expression of myogenic components has been examined using the rat L6 skeletal myoblast line [ 11 ]. Identification of regulatory components of myogenesis has been facilitated by the isolation of myoblast mutants impaired in myogenesis [12,13]. Transfection of these mutants with specific cDNAs provided valuable information not only on the regulatory components involved, but also the temporal order of expression of these components.…”

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confidence: 99%

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Involvement of the GLUT 3 transporter in myogenic regulation

et al. 1997

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We have recently demonstrated a close relationship between the GLUT 3 transporter and the myogenic ability of rat skeletal L6 myoblasts [1]. This investigation examined the effects of over‐and under‐expression of the GLUT 3 transporter on both biochemical and morphological differentiation. L6 transfectants expressing two to five times the normal L6 GLUT 3 transcript level were impaired in the expression of myogenesis‐associated genes, such as myogenin, MLC, MHC and TnT, and in myotube formation. Similar defects were also observed in myoblast mutants expressing less than 20% of the normal GLUT 3 level. Forced expression of an exogenous GLUT 3 cDNA could partially rescue the myogenic defect of these GLUT 3‐ mutants. However, such myogenic defects were not observed in L6 GLUT 3 antisense transfectants expressing 39% of the normal L6 GLUT 3 level. These data suggest that myogenic differentiation will proceed only within a critical level of the GLUT 3 transporter. The optimal GLUT 3 content for myogenesis ranges from around 2 × 105 to 5 × 105 molecules per cell in day 2 cultures; GLUT 3 levels outside this range have a negative effect on myogenesis. Our data suggest that GLUT 3 may regulate myogenesis by modulating the levels of signal transducers required for expression of myogenin and muscle‐specific contractile protein genes.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Involvement of the GLUT 3 transporter in myogenic regulation

et al. 1997

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Use of p112‐deficient myoblasts to determine the temporal order of the in vitro expression of myogenic components

Chen

1993

Journal Cellular Physiology

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The present investigation examines the function and site(s) of involvement of an ecto-protein kinase and its substrate protein (a cell surface 112 kDa protein) in the in vitro myogenic pathway. The phosphorylated 112 kDa protein (p112) has recently been shown to be involved in myogenesis. Not much information is currently available on the role of the ecto-protein kinase and the 112 kDa protein in modulating the expression of the myogenic factors and various muscle-specific proteins. Five different p112-deficient rat myoblasts were used to examine the temporal order of the in vitro expression of the myogenic components; namely, L6 myoblasts treated with BrdUrd or phloretin, a conditional p112-defective mutant (clone D1), an ecto-protein kinase-deficient mutant (clone F72), and a mutant defective in the 112 kDa protein (clone D1/S4). All these p112-deficient myoblasts were also impaired in myogenesis. The absence of p112, ecto-protein kinase, and/or the 112 kDa protein was found to have no effect on the Myf-5 mRNA level. However, the expected increase in NCAM and Myf-4 mRNAs was not observed in any of the p112-deficient myoblasts examined. This suggests that the p112 site of action is probably located upstream of the Myf-4 and NCAM sites in the myogenic pathway. While 7-28 fold increases in the MLC, MHC, and TnT transcripts were observed during myogenesis, such increases were not observed in the p112-deficient myoblasts. However, when mutant D1/S4 was transfected with the myf-4 cDNA, expression of Myf-4 in the transfectant resulted in increased level of the MLC, MHC, and TnT mRNAs, and in myotube formation, even though the Myf-5 and NCAM mRNA levels and p112 were not altered. This suggests that p112 may function by activating transcription of Myf-4, which will subsequently promote the expression of muscle-specific proteins and myotube formation. In the absence of p112, Myf-5 cannot activate the expression of Myf-4, NCAM, MLC, MHC, TnT, and myotube formation. If all these components are involved in the same myogenic pathway, then p112 may be acting downstream from Myf-5, and upstream from NCAM and Myf-4.

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Use of hexose transport mutants to examine the expression and properties of the rat myoblast GLUT 1 transport process

Xia

Mesmer

et al. 1995

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Rat L6 myoblasts were recently shown to possess the GLUT 1, 3 and 4 transporters, and not the GLUT 2 isoform [1]. This investigation examined the expression and properties of the GLUT 1 isoform. GLUT 1 transcript level was significantly reduced in cells grown at high densities and during myogenic differentiation. A comparison of the GLUT 1 and 4 transcript levels in myogenesis-competent and impaired cells revealed an inverse relationship between these two isoforms. This relationship was confirmed by studies using two independent spontaneous GLUT 3- GLUT 4- mutants, M1 and M3. These mutants possessed very high level of the GLUT 1 isoform, but negligible amount of the GLUT 3 and 4 isoforms. GLUT 1 expression was also subject to positive regulation. Glucose starvation was found to increase not only the levels of the GLUT 1 transcript and transporter, but also the intrinsic activity of the GLUT 1 transporter. Studies with M1 and M3 mutants revealed that the GLUT 1 transporter was not functional in glucose-grown cells, even though it was present at a very high level in the plasma membrane. This transporter became functional when cells were starved for glucose. The functional GLUT 1 transporter had an apparent Km value of around 0.9 mM, and was sensitive to cytochalasin B, phloretin, phlorizin and pCMBS.

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Involvement of Hexose transport in myogenic differentiation

Cited by 8 publications

References 44 publications

Involvement of the GLUT 3 transporter in myogenic regulation

Involvement of the GLUT 3 transporter in myogenic regulation

Use of p112‐deficient myoblasts to determine the temporal order of the in vitro expression of myogenic components

Use of hexose transport mutants to examine the expression and properties of the rat myoblast GLUT 1 transport process

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