TOR signaling is involved in PTTH-stimulated ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori

Gu, Shi‐Hong; Yeh, Wei-Lan; Young, Shun-Chieh; Lin, Pei‐Ling; Li, Sheng

doi:10.1016/j.ibmb.2011.12.010

Cited by 68 publications

(65 citation statements)

References 44 publications

(83 reference statements)

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“…Previous work has shown that rapamycin inhibits PTTH-stimulated ecdysone synthesis (Rybczynski, 2005). Indeed, PTTH has been shown to regulate 4E-BP and S6 kinase (S6K), a major target of TOR (Gu, Yeh, Young, Lin, & Li, 2012; Rybczynski, 2005). In addition to its stimulatory effect on ecdysone synthesis, PTTH has a non-steroidogenic trophic effect on PG growth and protein synthesis (Rybczynski, 2005; Rybczynski & Gilbert, 1994) and lack of PTTH reduces PG cell size (Ghosh, McBrayer, & O’Connor, 2010).…”

Section: Signals Converging On the Pgmentioning

confidence: 99%

Developmental Checkpoints and Feedback Circuits Time Insect Maturation

Rewitz

Yamanaka

O’Connor

2013

Current Topics in Developmental Biology

116

135

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The transition from juvenile to adult is a fundamental process that allows animals to allocate resource toward reproduction after completing a certain amount of growth. In insects, growth to a species-specific target size induces pulses of the steroid hormone ecdysone that triggers metamorphosis and reproductive maturation. The past few years have seen significant progress in understanding the interplay of mechanisms that coordinate timing of ecdysone production and release. These studies show that the neuroendocrine system monitors complex size-related and nutritional signals, as well as external cues, to time production and release of ecdysone. Based on results discussed here, we suggest that developmental progression to adulthood is controlled by checkpoints that regulate the genetic timing program enabling it to adapt to different environmental conditions. These checkpoints utilize a number of signaling pathways to modulate ecdysone production in the prothoracic gland. Release of ecdysone activates an autonomous cascade of both feedforward and feedback signals that determine the duration of the ecdysone pulse at each developmental transitions. Conservation of the genetic mechanisms that coordinate the juvenile-adult transition suggests that insights from the fruit fly Drosophila will provide a framework for future investigation of developmental timing in metazoans.

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Section: Signals Converging On the Pgmentioning

confidence: 99%

Developmental Checkpoints and Feedback Circuits Time Insect Maturation

Rewitz

Yamanaka

O’Connor

2013

Current Topics in Developmental Biology

116

135

View full text Add to dashboard Cite

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“…Since it was first shown to extend the longevity of wild-type mice in 2009, many studies have confirmed the antiaging effect of rapamycin (Arriola Apelo & Lamming 2016). The target of rapamycin (TOR) pathway responds to nutrient availability, energy status, and physiological stress and matches growth conditions to stimulation of anabolic and suppression of catabolic pathways in insects, flies, Caenorhabditis elegans, and mice (Thoreen et al 2009, Bjedov et al 2010, Gibbens et al 2011, Gu et al 2012, Mirth & Shingleton 2012. The kinase mTOR (mechanistic target of rapamycin) integrates growth-factor signaling with nutrient availability and directly regulates protein trans lation needed for cell growth and proliferation (Schmelzle & Hall 2000, Chiang & Abraham 2007.…”

Section: Introductionmentioning

confidence: 99%

Effects of rapamycin on life span and on expression of TOR and S6K in Brachionus calyciflorus (Rotifera)

Xu¹,

Liu²,

Su³

et al. 2017

Aquat. Biol.

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The mechanistic target of rapamycin (mTOR) coordinates a complex signal pathway from translation to autophagy that is a key regulator of not only growth and proliferation but also metabolism and aging. mTOR is sensitive to many environmental and endocrine stimuli. We investigated the influence of TOR signaling on aging and reproduction of the rotifer Brachionus calyciflorus using rapamycin as an exogenous inhibitor. We found that 2 and 4 µM rapamycin extended B. calyciflorus life span by 15 and 22%, respectively compared with controls (p < 0.05). The reproductive peak was significantly delayed by rapamycin at 2 and 4 µM (p < 0.01), but the pre-and post-reproduction periods were not significantly different from controls (p > 0.05). Partial cDNAs coding 375 bp for TOR and 951 bp for S6 kinase (S6K ) were obtained from B. calyciflorus expressed sequence tags. The identities of the deduced amino acid sequences of B. calyciflorus cDNAs to their human orthologs were 58% for TOR and 68% for S6K. TOR and S6K mRNA expression were up-or down-regulated by different rapamycin concentrations (0.5, 1, 2, 4, 8, and 16 µM) and treatment intervals (control, 12, 24, 36, and 48 h). The results indicated that TOR inhibition acted additively to extend rotifer life span, with up-and down-regulation simultaneously impacting reproduction and gene expression.

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“…Studies from Lepidoptera, for example, show that PTTH elevates calcium (Ca 2+ ) flux and cAMP levels in PTG cells (Smith et al, 1985; Gu et al 2000; Fellner et al, 2005), while demonstrating that cAMP analogs stimulate PTGs to produce ECD in the absence of PTTH (Smith et al, 1984). Experiments from D. melanogaster and Bombyx mori also implicate insulin and target of rapamycin (TOR) pathway signaling in regulating PTG function (Ishizaki and Suzuki, 1994; Mizoguchi and Okamoto, 2013; Columbani et al, 2005; Walkiewicz and Stern, 2009; Ohhara et al, 2015; Gu et al, 2011; 2012; 2015). An early study by Shapiro (1983) before ILPs and OEH were known showed that a cAMP analog and head extract both stimulate A. aegypti ovaries to produce ECD.…”

Section: Introductionmentioning

confidence: 99%

Calcium influx enhances neuropeptide activation of ecdysteroid hormone production by mosquito ovaries

McKinney

Eum

Dhara

et al. 2016

Insect Biochemistry and Molecular Biology

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A critical step in mosquito reproduction is the ingestion of a blood meal from a vertebrate host. In mosquitoes like Aedes aegypti, blood feeding stimulates the release of ovary ecdysteroidogenic hormone (OEH) and insulin-like peptide 3 (ILP3). This induces the ovaries to produce ecdysteroid hormone (ECD), which then drives egg maturation. In many immature insects, prothoracicotropic hormone (PTTH) stimulates the prothoracic glands to produce ECD that directs molting and metamorphosis. The receptors for OEH, ILP3 and PTTH are different receptor tyrosine kinases with OEH and ILP3 signaling converging downstream in the insulin pathway and PTTH activating the mitogen-activated protein kinase pathway. Calcium (Ca2+) flux and cAMP have also been implicated in PTTH signaling, but the role of Ca2+ in OEH, ILP3, and cAMP signaling in ovaries is unknown. Here, we assessed whether Ca2+ flux affects OEH, ILP3, and cAMP activity in A. aegypti ovaries and also asked whether PTTH stimulated ovaries to produce ECD. Results indicated that Ca2+ flux enhanced but was not essential for OEH or ILP3 activity, whereas cAMP signaling was dependent on Ca2+ flux. Recombinant PTTH from Bombyx mori fully activated ECD production by B. mori PTGs, but exhibited no activity toward A. aegypti ovaries. Recombinant PTTH from A. aegypti also failed to stimulate either B. mori PTGs or A. aegypti ovaries to produce ECD. We discuss the implications of these results in the context of mosquito reproduction and ECD biosynthesis by insects generally.

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TOR signaling is involved in PTTH-stimulated ecdysteroidogenesis by prothoracic glands in the silkworm, Bombyx mori

Cited by 68 publications

References 44 publications

Developmental Checkpoints and Feedback Circuits Time Insect Maturation

Developmental Checkpoints and Feedback Circuits Time Insect Maturation

Effects of rapamycin on life span and on expression of TOR and S6K in Brachionus calyciflorus (Rotifera)

Calcium influx enhances neuropeptide activation of ecdysteroid hormone production by mosquito ovaries

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