Inactivation and Reactivation of Phosphoprotein Phosphatase of Rabbit Skeletal Muscle

Kato, Kanefusa; Kobayashi, Masanao; Sato, Shizuko

doi:10.1093/oxfordjournals.jbchem.a130787

Cited by 45 publications

(6 citation statements)

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“…The question of how metals affect phosphorylase phosphatase is an old one. It has long been known that divalent cations, in particular Mn 2ϩ and Co 2ϩ , can activate certain phosphorylase phosphatase preparations (Merlevede and Riley, 1966;Kato and Bishop, 1972;Kato et al, 1975;Ullman and Perlman, 1975;Khatra and Soderling, 1978;Khandelwal and Kasmani, 1980;Brautigan et al, 1980Brautigan et al, , 1982. It has been suggested that the phosphatase present in these preparations is a metalloenzyme (Burchell and Cohen, 1978;Hsiao et al, 1978;Khatra and Soderling, 1978;Defreyn et al, 1979;Mackenzie et al, 1980 (Yan and Graves, 1982 (Villa-Moruzzi et al, 1984) or a preparation containing a high molecular weight form of PP1 (Brautigan et al, 1980) …”

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confidence: 99%

Activation of Protein Phosphatase 1

Chu

Lee

Schlender

1996

Journal of Biological Chemistry

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confidence: 99%

Activation of Protein Phosphatase 1

Chu

Lee

Schlender

1996

Journal of Biological Chemistry

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“…It has long been known that divalent cations, in particular Mn 2+ and Mg 2+ , activate certain phosphatase preparations (Kato et al, 1975). Indeed, it has been shown that some, such as Mn 2+ , enhances intrinsic calcineurin phosphatase activity, while others, like Ni 2+ , Fe 2+ , Zn 2+ , and Cu 2+ , are strongly inhibitory (Gupta et al, 1990).…”

Section: Discussionmentioning

confidence: 99%

Effects of cations on ceramide-activated protein phosphatase 2A

Galadari

Hago²,

Patel³

2001

Exp Mol Med

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Characterization of ceramide-effector(s), which includes protein phosphatase 2A (PP2A) is an important prelude to understanding the molecular basis of sphingolipid-mediated biological effects such as cell growth, differentiation and apoptosis. Recently, the existence of a metal-dependent form of PP2A has been reported (Cai et al., 1995). In this study, we investigated the effects of metal ions and chelators on ceramide-activated PP2A (CAPP). Our study demonstrates that at 0.5 mM concentration, Mg 2+ appears to have no significant effect on either basal or ceramide-stimulated phosphatase activities, whereas Ca 2+ stimulated the basal phosphatase activity, but was inhibitory towards CAPP. Moreover, the divalent cations Cr 2+ , Mn 2+ , Fe 2+ , Ni 2+ , Cu 2+ and Zn 2+ were tested and all were found to be inhibitory towards both CAPP and basal phosphatase activities. By contrast, Cs + and Li + had almost no effect on CAPP, although both stimulated basal phosphatase activity. The effects of EDTA and EGTA were tested and it was observed that EDTA decreased CAPP activity in a dose-dependent fashion, but had no effect upon basal phosphatase activity. These results suggest that CAPP is a metal-dependent protein, but, because Ca 2+ inhibitied CAPP and EGTA was much less potent than EDTA in inhibiting CAPP, Ca 2+ is unlikely to be its metal cofactor.

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“…The fact that the response to GTP is fully reversed by injecting Mg2+ not only strengthens this interpretation but also provides a clue as to the nature of the second cause. Thus, for example, the effect of Mg2+ removal would be inhibition of phosphoprotein phosphatase, as observed in rabbit skeletal muscle (Kato, Kobayashi & Sato, 1975;Khatra & Soderling, 1977) and hence, phosphorylation would exceed dephosphorylation. Alternatively, GTP may remove internal trace elements such as Fe and Zn which are inhibitory to phosphoprotein phosphatase, e.g.…”

Section: Discussionmentioning

confidence: 99%

Stimulation by injected guanosine triphosphate of the sodium efflux in barnacle muscle fibres.

Bittar¹,

Nwoga²

1982

The Journal of Physiology

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1. A study has been made of the mechanism by which injected disodium GTP stimulates the ouabain‐insensitive Na efflux in single muscle fibres from the barnacle, Balanus nubilus. 2. Injection of GTPNa2 causes a stimulatory response which is usually transitory and almost completely reversed by injecting MgCl2 (but not KCl). 3. Injected 5'‐guanylylimidodiphosphate, Gpp(NH)p, mimics this action of GTP but the reversal seen with injected Mg2+ is less pronounced. 4. (i) Pre‐treatment of these fibres with verapamil reduces the size of the stimulatory response to GTP and Gpp(NH)p. (ii) Pre‐injection of protein kinase inhibitor (PKI) or regulatory subunits reduces the response as well. (iii) Pre‐treatment with imipramine or trifluoperazine reduces the response to injected GTP; in combination with verapamil, a greater reduction in response is seen. 5. Injection of EDTA leads to a stimulatory response which is transitory. This response is largely abolished by verapamil. 6. Injection of cholera toxin leads to a sustained stimulatory rather than a transitory response. GTP or Gpp(NH)p when injected following peak stimulation by cholera toxin leads to a moderate sustained stimulation. 7. These results support the view that the stimulatory response to injected GTPNa2 is the result of activation of Ca2+ channels and of increased availability of GTPMg and that these two conditions bring about activation of adenylate cyclase and hence activation of cyclic AMP‐protein kinase by newly formed cyclic AMP.

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Inactivation and Reactivation of Phosphoprotein Phosphatase of Rabbit Skeletal Muscle

Cited by 45 publications

References 0 publications

Activation of Protein Phosphatase 1

Activation of Protein Phosphatase 1

Effects of cations on ceramide-activated protein phosphatase 2A

Stimulation by injected guanosine triphosphate of the sodium efflux in barnacle muscle fibres.

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