Stimulation of protein synthesis and phospholipase D activity by vasopressin and phorbol ester in L6 myoblasts

Thompson, Michael G.; Mackie, Steven C.; Morrison, Kenneth S.; Thom, Amanda; Palmer, Robert M.

doi:10.1016/0167-4889(94)90191-0

Cited by 15 publications

(20 citation statements)

References 35 publications

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“…We have previously shown in L6 myoblasts that the EC 50 for vasopressin stimulation of transcription is 10-fold higher than that for [ 3 H]PtdBuOH formation and [ 3 H]choline release (4). Data from the current study show that this is also true for [ 14 C]ethanolamine release.…”

Section: Stimulation Of Protein Synthesis By Exogenous Pld-supporting

confidence: 70%

“…Data from the current study show that this is also true for [ 14 C]ethanolamine release. Furthermore, the maximal stimulation of protein synthesis observed with exogenous PLD at 6 h was 12%, whereas an increase of 30% or more was elicited by vasopressin (4). Thus, while data in this and our previous study (4) support a link between the activation of PLD and the stimulation of translation by TPA, it also implies that, at best, activation of PLD is only part of the mechanism by which vasopressin increases protein synthesis in these cells.…”

Section: Stimulation Of Protein Synthesis By Exogenous Pld-contrasting

confidence: 39%

“…Interestingly, however, TPA increased protein synthesis only during short term (90-min) incubations, which were neither blocked by the transcription inhibitor, actinomycin D, nor accompanied by increases in RNA, implying an effect only on translation. In contrast, the synthesis response to vasopressin was detected solely over longer term (6-h) incubations, where increases in RNA content and sensitivity to actinomycin D were observed, demonstrating effects on transcription (4).…”

mentioning

confidence: 88%

“…In L6 skeletal muscle cells, we have demonstrated that TPA and vasopressin stimulate both protein synthesis and a phospholipase D (PLD) that degrades phosphatidylcholine. Furthermore, incubation of L6 cells with exogenous PLD mimicked the effects of TPA and vasopressin on protein synthesis, implying a link between the two events (4). Interestingly, however, TPA increased protein synthesis only during short term (90-min) incubations, which were neither blocked by the transcription inhibitor, actinomycin D, nor accompanied by increases in RNA, implying an effect only on translation.…”

mentioning

confidence: 93%

“…Phase separation was achieved with chloroform (1.25 ml) and water (1.25 ml). The upper phase was removed, and the intracellular metabolites were separated (23) (4).…”

Section: Determination Of Intra-and Extracellular [ 14 C]ethanolaminementioning

confidence: 99%

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Regulation of Phospholipase D in L6 Skeletal Muscle Myoblasts

Thompson¹,

Mackie²,

Thom³

et al. 1997

Journal of Biological Chemistry

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The addition of vasopressin or 12-O-tetradecanoylphorbol-13-acetate (TPA) to prelabeled L6 myoblasts elicited increases in [ 14 C]ethanolamine release, suggesting the activation of phospholipase D activity or activities. While the effects of both agonists on intracellular release were rapid and transient, when extracellular release of [ 14 C]ethanolamine was measured, the effect of vasopressin was again rapid and transient, whereas that of TPA was delayed but sustained. Effects of both agonists on intra-and extracellular release were inhibited by the protein kinase C (PKC) inhibitor, Ro-31-8220, and PKC down-regulation by preincubation with TPA. The formation of phosphatidylbutanol elicited by vasopressin and TPA mirrored their effects on extracellular [ 14 C]ethanolamine release in that the former was transient, whereas the latter was sustained. Responses to both agonists were abolished by PKC down-regulation. When protein synthesis was examined, the stimulation of translation by TPA and transcription by vasopressin were inhibited by Ro-31-8220. In contrast, down-regulation of PKC inhibited the synthesis response to TPA but not vasopressin. Furthermore, following down-regulation, the effect of vasopressin was still blocked by the PKC inhibitors, Ro-31-8220 and bisindolylmaleimide. Analysis of PKC isoforms in L6 cells showed the presence of ␣, ⑀, ␦, , , and . Down-regulation removed both cytosolic (␣) and membrane-bound (⑀ and ␦) isoforms. Thus, the elevation of phospholipase D activity or activities induced by both TPA and vasopressin and the stimulation of translation by TPA involves PKC-␣, -⑀, and/or -␦. In contrast, the increase in transcription elicited by vasopressin involves , , and/or . Hence, although phospholipase D may be linked to increases in translation elicited by TPA, it is not involved in the stimulation of transcription by vasopressin.Loss of skeletal muscle is an acute metabolic response to infection and neoplastic disease and results from a decrease in the rate of protein synthesis and an increase in the rate of protein degradation (e.g. see Refs. 1-3). To reverse this process, an understanding of the signaling pathways regulating protein turnover is essential.We have used 12-O-tetradecanoylphorbol-13-acetate (TPA) 1 and vasopressin to investigate the coordinate regulation of protein turnover. Previous studies in this (4 -6) and other (7) laboratories have shown that these two agents both stimulate protein synthesis and reduce the release of N -methylhistidine, a marker of myofibrillar protein degradation from intact skeletal muscle in vitro and skeletal muscle cells in culture. However, the mechanism(s) mediating these effects are poorly understood.Many extracellular signals such as hormones, neurotransmitters, and growth factors elicit their response by activating an intracellular signaling cascade that is initiated by the hydrolysis of membrane phospholipids (8 -11). In L6 skeletal muscle cells, we have demonstrated that TPA and vasopressin stimulate both protein synthesis and a phospholip...

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Section: Stimulation Of Protein Synthesis By Exogenous Pld-supporting

confidence: 70%

Section: Stimulation Of Protein Synthesis By Exogenous Pld-contrasting

confidence: 39%

mentioning

confidence: 88%

mentioning

confidence: 93%

“…Phase separation was achieved with chloroform (1.25 ml) and water (1.25 ml). The upper phase was removed, and the intracellular metabolites were separated (23) (4).…”

Section: Determination Of Intra-and Extracellular [ 14 C]ethanolaminementioning

confidence: 99%

See 3 more Smart Citations

Regulation of Phospholipase D in L6 Skeletal Muscle Myoblasts

Thompson¹,

Mackie²,

Thom³

et al. 1997

Journal of Biological Chemistry

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Role of phospholipase C and D signalling pathways in vasopressin-dependent myogenic differentiation

et al. 1997

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Arg8-vasopressin (AVP) is a potent inducer of myogenic differentiation stimulating the expression of myogenic regulatory factors. To understand the mechanism of its effect on myogenesis, we investigated the early signals induced by AVP in myogenic target cells. In the rat skeletal muscle cell line L6, AVP selectively stimulates phosphatidylinositol (PtdIns) and phosphatidylcholine (PtdCho) breakdown, through the activation of phospholipases C and D (PLC, PLD), as shown by the generation of Ins(1,4,5)P3 and phosphatidylethanol (PtdEtOH), respectively. AVP induces the biphasic increase of sn-1,2-diacylglycerol (DAG) consisting in a rapid peak followed by a sustained phase, and the monophasic generation of phosphatidic acid (PA). Propranolol (a PA phosphatase inhibitor) and Zn2+ (a PLD inhibitor), abolish the sustained phase of DAG generation. Our data indicate that PtdIns-PLC activity is mainly responsible for the rapid phase of AVP-dependent DAG generation, whereas the sustained phase is dependent upon PtdCho-PLD activity and PA dephosphorylation, ruling out any significant role of DAG kinase. Modifications of PA level correlate with parallel changes of PLC activity, indicating a possible cross-talk between the two signal transduction pathways in the intact cell. PLD activation is elicited at AVP concentrations two orders of magnitude lower than those required for PLC activation. The differentiation of L6 myoblasts into multinucleated fibers is stimulated significantly by AVP at concentrations at which PLD, but not PLC, is activated. These data provide the first evidence for an important role of PLD in the mechanism of AVP-induced muscle differentiation.

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Stimulation of protein and DNA synthesis in mouse C₂C₁₂ satellite cells: Evidence for phospholipase d‐dependent and ‐independent pathways

Morrison¹,

Mackie²,

Palmer³

et al. 1995

Journal Cellular Physiology

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In C2C12 myoblasts, 12-O-tetradecanoylphorbol-13-acetate (TPA) stimulated a phospholipase D (PLD) to degrade phosphatidylcholine (PC) as measured by the release of choline and an increase in the formation of phosphatidic acid (PA) (or phosphatidylbutanol [PtdBuOH] in the presence of 0.5% butanol). Exogenous PLD also stimulated choline release, PA and PtdBuOH formation. The protein kinase C (PKC) inhibitor, Ro-31-8220, and PKC downregulation significantly inhibited the effects of TPA but Ro-31-8220 had no effect on PLD action. Neither basic Fibroblast Growth Factor (bFGF) or Epidermal Growth Factor (EGF) increased PLD activity. All agonists stimulated protein synthesis during both a 90 min and a 6 hr incubation and increased RNA accretion after 6 hr. The response at 90 min was not inhibited by the transcription inhibitor, actinomycin D. Ro-31-8220 and PKC downregulation significantly inhibited all the effects of TPA. In contrast, Ro-31-8220 significantly inhibited the increase in RNA accretion elicited by PLD but had no effect on the ability of agonists other than TPA to enhance protein synthesis. All agonists also stimulated thymidine incorporation into DNA. The effects of EGF, bFGF, and PLD were rapid and transient whereas that of TPA was delayed and sustained. Ro-31-8220 and PKC downregulation significantly inhibited the response due to TPA. Furthermore, Ro-31-8220 also significantly inhibited the effects elicited by EGF and PLD but not that induced by bFGF. In differentiated myotubes, TPA and PLD, but not bFGF or EGF, again stimulated choline release and PtdBuOH formation. However, all agents failed to stimulate protein synthesis and RNA accretion. The data demonstrate the presence in C2C12 myoblasts, but not differentiated myotubes, of both a PLD-dependent and PLD-independent pathway(s) leading to the stimulation of protein synthesis, RNA accretion, and DNA synthesis.

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Stimulation of protein synthesis and phospholipase D activity by vasopressin and phorbol ester in L6 myoblasts

Cited by 15 publications

References 35 publications

Regulation of Phospholipase D in L6 Skeletal Muscle Myoblasts

Regulation of Phospholipase D in L6 Skeletal Muscle Myoblasts

Role of phospholipase C and D signalling pathways in vasopressin-dependent myogenic differentiation

Stimulation of protein and DNA synthesis in mouse C₂C₁₂ satellite cells: Evidence for phospholipase d‐dependent and ‐independent pathways

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Stimulation of protein synthesis and phospholipase D activity by vasopressin and phorbol ester in L6 myoblasts

Cited by 15 publications

References 35 publications

Regulation of Phospholipase D in L6 Skeletal Muscle Myoblasts

Regulation of Phospholipase D in L6 Skeletal Muscle Myoblasts

Role of phospholipase C and D signalling pathways in vasopressin-dependent myogenic differentiation

Stimulation of protein and DNA synthesis in mouse C2C12 satellite cells: Evidence for phospholipase d‐dependent and ‐independent pathways

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Stimulation of protein and DNA synthesis in mouse C₂C₁₂ satellite cells: Evidence for phospholipase d‐dependent and ‐independent pathways