Different Ca2+ signalling cascades manifested by mastoparan in the prothoracic glands of the tobacco hornworm, Manduca sexta, and the silkworm, Bombyx mori

Dedos, Skarlatos G.; Wicher, Dieter; Kaltofen, Sabine; Birkenbeil, Heiner

doi:10.1002/arch.20180

Cited by 4 publications

(2 citation statements)

References 26 publications

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“…The PTTH receptor is known as Torso, first characterized in Drosophila embryos (Casanova and Struhl, 1989; Li, 2005; Rewitz et al, 2009). Unlike insulin, PTTH increases intracellular levels of cyclic AMP, through a PTTH-stimulated increase in intracellular calcium and the activation of a calcium-sensitive adenylyl cyclase (Smith et al, 1984, 1985; Meller et al, 1988; Dedos et al, 2005, 2007; Fellner et al, 2005). Increased intracellular calcium also results in activation of mitogen-activated protein kinases (MAPkinases) including MEK and ERK (Rybczynski and Gilbert, 2003).…”

Section: Introductionmentioning

confidence: 99%

Insulin signaling pathways in lepidopteran ecdysone secretion

2014

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Molting and metamorphosis are stimulated by the secretion of ecdysteroid hormones from the prothoracic glands. Insulin-like hormones have been found to enhance prothoracic gland activity, providing a mechanism to link molting to nutritional state. In silk moths (Bombyx mori), the prothoracic glands are directly stimulated by insulin and the insulin-like hormone bombyxin. Further, in Bombyx, the neuropeptide prothoracicotropic hormone (PTTH) appears to act at least in part through the insulin-signaling pathway. In the prothoracic glands of Manduca sexta, while insulin stimulates the phosphorylation of the insulin receptor and Akt, neither insulin nor bombyxin II stimulate ecdysone secretion. Involvement of the insulin-signaling pathway in Manduca prothoracic glands was explored using two inhibitors of phosphatidylinositol-3-kinase (PI3K), LY294002 and wortmannin. PI3K inhibitors block the phosphorylation of Akt and 4EBP but have no effect on ecdysone secretion, or on the phosphorylation of the MAPkinase, ERK. Inhibitors that block phosphorylation of ERK, including the MEK inhibitor U0126, and high doses of the RSK inhibitor SL0101, effectively inhibit ecdysone secretion. The results highlight differences between the two lepidopteran insects most commonly used to directly study ecdysteroid secretion. In Bombyx, the PTTH and insulin-signaling pathways intersect; both insulin and PTTH enhance the phosphorylation of Akt and stimulate ecdysteroid secretion, and inhibition of PI3K reduces ecdysteroid secretion. By contrast, in Manduca, the action of PTTH is distinct from insulin. The results highlight species differences in the roles of translational regulators such as 4EBP, and members of the MAPkinase pathway such as ERK and RSK, in the regulation of insect ecdysone secretion, and in the impact of nutritionally-sensitive hormones such as insulin in the control of ecdysone secretion and molting.

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Section: Introductionmentioning

confidence: 99%

Insulin signaling pathways in lepidopteran ecdysone secretion

2014

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“…Mastoparan activates trimeric G proteins [19,20] and increases intracellular Ca 2+ [21,22], which is important for the activation of the protein kinase Cα (PKCα) [23]. PKCα and PLD1 are co-localized [24,25] and are translocated to the plasma membrane upon Ca 2+ -mediated activation of PKCα [26–28].…”

Section: Resultsmentioning

confidence: 99%

The Influence of Polyunsaturated Fatty Acids on the Phospholipase D Isoforms Trafficking and Activity in Mast Cells

Basiouni

Fuhrmann

Schümann

2013

IJMS

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The impact of polyunsaturated fatty acid (PUFA) supplementation on phospholipase D (PLD) trafficking and activity in mast cells was investigated. The enrichment of mast cells with different PUFA including α-linolenic acid (LNA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), linoleic acid (LA) or arachidonic acid (AA) revealed a PUFA-mediated modulation of the mastoparan-stimulated PLD trafficking and activity. All PUFA examined, except AA, prevented the migration of the PLD1 to the plasma membrane. For PLD2 no PUFA effects on trafficking could be observed. Moreover, PUFA supplementation resulted in an increase of mastoparan-stimulated total PLD activity, which correlated with the number of double bonds of the supplemented fatty acids. To investigate, which PLD isoform was affected by PUFA, stimulated mast cells were supplemented with DHA or AA in the presence of specific PLD-isoform inhibitors. It was found that both DHA and AA diminished the inhibition of PLD activity in the presence of a PLD1 inhibitor. By contrast, only AA diminished the inhibition of PLD activity in the presence of a PLD2 inhibitor. Thus, PUFA modulate the trafficking and activity of PLD isoforms in mast cells differently. This may, in part, account for the immunomodulatory effect of unsaturated fatty acids and contributes to our understanding of the modulation of mast cell activity by PUFA.

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Prothoracicotropic Hormone

Smith

2012

Insect Endocrinology

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Different Ca²⁺ signalling cascades manifested by mastoparan in the prothoracic glands of the tobacco hornworm, Manduca sexta, and the silkworm, Bombyx mori

Cited by 4 publications

References 26 publications

Insulin signaling pathways in lepidopteran ecdysone secretion

Insulin signaling pathways in lepidopteran ecdysone secretion

The Influence of Polyunsaturated Fatty Acids on the Phospholipase D Isoforms Trafficking and Activity in Mast Cells

Prothoracicotropic Hormone

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