Exocytosis induction in Paramecium tetraurelia cells by exogenous phosphoprotein phosphatase in vivo and in vitro: possible involvement of calcineurin in exocytotic membrane fusion.

Momayezi, Massoud; Lumpert, Christine J.; Kersken, Helmut; Gras, Ute; Plattner, Helmut; Krinks, Marie; Klee, Claude B.

doi:10.1083/jcb.105.1.181

Cited by 94 publications

(63 citation statements)

References 61 publications

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“…For calcineurin inhibition, anti-calcineurin antibodies (Momayezi et al,, 1987) were present throughout the experiment. In control experiments total rabbit IgGs (Miles, UK) were used.…”

Section: Transmitter Releasementioning

confidence: 99%

Ba2+ replaces Ca2+/calmodulin in the activation of protein phosphatases and in exocytosis of all major transmitters

Verhage

Hens

Graan

et al. 1995

European Journal of Pharmacology: Molecular Pharmacology

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Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. AbstractExocytosis from nerve terminals is triggered by depolarization-evoked Ca*+ entry, which also activates calmodulin and stimulates protein phosphorylation. Ba2+ is believed to replace Ca2+ m triggering exocytosis without activation of calmodulin and can therefore be '+ used to unravel aspects of presynaptic function. We have analysed the cellular actions of Ba in relation to its effect on transmitter release from isolated nerve terminals. Barium evoked specific release of amino acid transmitters, catecholamines and neuropeptides (EC,, 0.2-0.5 mM), similar to K'/Ca" -evoked release both in extent and kinetics. Ba2 +-and Ca2+ -evoked release were not additive. In contrast to Ca'+, Ba2+ triggered release which was insensitive to trifluoperizine and hardly stimulated protein phosphorylation. These observations are in accordance with the ability of Ba2+ to replace CaZf m exocytosis without activating calmodulin. Nevertheless, calmodulin appears to be essential for regular (Cazf -triggered) exocytosis, given its sensitivity to trifluoperizine.Both Ba2+-and Ca'+-evoked release were blocked by okadaic acid. Furthermore, anti-calcineurin antibodies decreased Ba'+-evoked release. In conclusion, BaZf replaces Ca'+/calmodulin in the release of the same transmitter pool. Calmodulin-dependent phosphorylation appears not to be essential for transmitter release. Instead, our data implicate both CaZf -dependent and -independent dephosphorylation in the events prior to neurotransmitter exocytosis.Keywords: Exocytosis; Ba*+; Ca'+-dependent release; Calmodulin; Okadaic acid, Phosphatase IntroductionThe regulated exocytosis of neurotransmitters and neuropeptides is triggered by depolarization evoked Ca*+ entry. Although this process is reasonably specific for Ca2+, several divalent cations with similar physico-chemical properties, such as Ba'+, Sr2+ and Pb2+, were found to evoke transmitter release as well (Zengel and Magleby, 1980;Augustine and Eckert, 1984;Heldman et al., 1989;Shao and Suszkiw, 1991;McMahon and Nicholls, 1993;Sihra et al., 1993). Among these, Ba2+ is the best documented and probably the most effective. However, Ba2+ was found to be ineffective in binding and activating the

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“…For calcineurin inhibition, anti-calcineurin antibodies (Momayezi et al,, 1987) were present throughout the experiment. In control experiments total rabbit IgGs (Miles, UK) were used.…”

Section: Transmitter Releasementioning

confidence: 99%

Ba2+ replaces Ca2+/calmodulin in the activation of protein phosphatases and in exocytosis of all major transmitters

Verhage

Hens

Graan

et al. 1995

European Journal of Pharmacology: Molecular Pharmacology

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“…The ATPase activity of axonemal dynein, notably of the 14S component, is enhanced greatly by CaM in Tetrahymena (Blum et aI., 1980). A Ca 2 +/CaM-activated protein phosphatase type 2B (=calcineu-rin) may be involved in trichocyst exocytosis (Momayezi et al, 1987b). Vacuole fusion in yeast has been shown to be a CaM-dependent process (Peters and Mayer, 1998).…”

Section: Helmut Plattner and Norbert Klaukementioning

confidence: 99%

“…No clear answer is available from higher cells. Yet in catecholamine-or neuropeptide-secreting cells (Hens et aI., 1998), just as in Paramecium cells (Momayezi et al, 1987b), the activation of PP2B (CaN) has been proposed to be a crucial step during exocytosis on the basis of inhibitory antibody effects in both cases. The role of the Ca 2 + signal for membrane fusion and pore expansion is shown schematically in Fig.…”

mentioning

confidence: 99%

“…For a summary of CaBPs in ciliates, see Table V. (trichocysts, cytoproct;Knochel et al, 1996) Multiple localization (Momayezi et al, 1986) Exocytosis regulation (Momayezi et al, 1987b) Sequence homologies in some Ca z +-activated protein kinases (Kim et al, 1998) Function and physiological Ca z + requirement not yet established (Son et al, 1993) Function and physiological Ca z +…”

mentioning

confidence: 99%

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Calcium in ciliated protozoa: Sources, regulation, and calcium-regulated cell functions

Plattner

Klauke²

2001

International Review of Cytology

105

121

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In ciliates, a variety of processes are regulated by Ca 2 ', e.g., exocytosis, endocytosis, ciliary beat, cell contraction, and nuclear migration. Differential microdomain regulation may occur by activation of specific channels in different cell regions (e.g., voltagedependent Ca 2 ' channels in cilia), by local, nonpropagated activation of subplasmalemmal Ca stores (alveolar sacs), by different sensitivity thresholds, and eventually by interplay with additional second messengers (cilia). During stimulus-secretion coupling, Ca 2 ' as the only known second messenger operates at -5 f.tM, whereby mobilization from alveolar sacs is superimposed by "store-operated Ca

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“…Both, CaM [41] and CaN [42J are abundant in the Paramecium cortex. Injection of anti-CaN ABs, derived from bovine brain, inhibit exocytosis [43]. A protein with considerable resemblance to mammalian CaN has been isolated, biochemically characterised.…”

Section: Introductionmentioning

confidence: 99%

Molecular aspects of rapid, reversible, Ca2+-dependent de-phosphorylation of pp63/parafusin during stimulated exo-endocytosis in Paramecium cells

Plattner

Kissmehl

2005

Cell Calcium

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Calf signalling governs stimulated exocytosis and exocytosis-coupled endocytosis also in Paramecium cells. Upon stimulation, the ::s10 3 dense-core exocytotic organelles (trichocysts) can be synchronously (80 ms) released, followed by endocytotic membrane resealing (350 ms) and retrieval. Paramecium is the most synchronous dense-core exocytotic system known, allowing to dissect rapidly reversible Calf -dependent phenomena. This holds for the reversible de-/re-phosphorylation cycle of a 63 kD phosphoprotein, pp63/parafusin (pf), which we have cloned, immuno-Iocalised, and characterised as phosphoglucomutase. the enzyme funneling glucose into the glycolytic pathway. It was isolated ex vivo. followed by MALDl analysis, while X-ray structure analysis was performed after heterologous expression. We found multiple phosphorylation of superficial SerlThr residues. Although present also in exo-mutants. pp63/pf is selectively de-phosphorylated only in exo+ strains during synchronous exocytosis (80 ms) and re-phosphorylated within~20 s, Le., the time required to re-establish [Calf] homeostasis. We have isolated relevant protein phosphatases and kinases and probed their activity on pp63/pf in vitro. We consider CalfIcalmodulin-activated PP2B (calcineurin, whose subunits have been cloned) relevant for de-phosphorylation. Re-phosphorylation can be achieved by two protein kinases that also have been cloned. One is activated by cGMP (PKG) which in turn is formed by Calf-activated guanylate cyclase. Another kinase, casein kinase 2. is inhibited by Calf and. hence, activated with some delay in parallel to decreasing [Calf] after exocytosis. In total, several Calf -sensitive cycles cooperate whose protein components have been localised to the cell cortex. Regulation of the phosphorylation degree of pp63/pf may affect structure binding on a microscale and/or its enzymatic activity. All this may serve fueling substrate into glycolysis with increased ATP re-formation (compromised in exo-mutants) and NADH formation. with effects on Calf signalling including mobilisation from cortical stores (alveolar sacs) and overall effects on ATP and Ca 2 + dynamics during synchronous exo-and endocytosis.

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Exocytosis induction in Paramecium tetraurelia cells by exogenous phosphoprotein phosphatase in vivo and in vitro: possible involvement of calcineurin in exocytotic membrane fusion.

Abstract: Abstract. Since it had been previously shown that in Paramecium cells exocytosis involves the

Cited by 94 publications

References 61 publications

Ba2+ replaces Ca2+/calmodulin in the activation of protein phosphatases and in exocytosis of all major transmitters

Ba2+ replaces Ca2+/calmodulin in the activation of protein phosphatases and in exocytosis of all major transmitters

Calcium in ciliated protozoa: Sources, regulation, and calcium-regulated cell functions

Molecular aspects of rapid, reversible, Ca2+-dependent de-phosphorylation of pp63/parafusin during stimulated exo-endocytosis in Paramecium cells

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