Direct effects of hypoxia and nitric oxide on ecdysone secretion by insect prothoracic glands

DeLalio, Leon J.; Dion, Sara M.; Bootes, Abigail; Smith, Wendy A.

doi:10.1016/j.jinsphys.2015.02.009

Cited by 13 publications

(8 citation statements)

References 73 publications

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“…Indeed, in Bombyx mori a low but sustained ecdysteroidogenesis response to pulsatile PTTH release has been seen in the early penultimate larval instar (Gu et al, 2000) -and this is likely to reflect the low levels of Torso predicted in the PG at this stage (Gu et al, 2000;Rewitz et al, 2009). Also consistent with our hypothesis, in the tobacco hornworm (M. sexta), reducing oxygen tension increases Torso mRNA levels (DeLalio et al, 2015) and induces precocious molting (Callier and Nijhout, 2011) -which we suggest reflects a more transient response to PTTH.…”

Section: Discussionsupporting

confidence: 85%

Structural Basis of Neurohormone Perception by the Receptor Tyrosine Kinase Torso

et al. 2015

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In insects, brain-derived Prothoracicotropic hormone (PTTH) activates the receptor tyrosine kinase (RTK) Torso to initiate metamorphosis through the release of ecdysone. We have determined the crystal structure of silkworm PTTH in complex with the ligand-binding region of Torso. Here we show that ligand-induced Torso dimerization results from the sequential and negatively cooperative formation of asymmetric heterotetramers. Mathematical modeling of receptor activation based upon our biophysical studies shows that ligand pulses are "buffered" at low receptor levels, leading to a sustained signal. By contrast, high levels of Torso develop the signal intensity and duration of a noncooperative system. We propose that this may allow Torso to coordinate widely different functions from a single ligand by tuning receptor levels. Phylogenic analysis indicates that Torso is found outside arthropods, including human parasitic roundworms. Together, our findings provide mechanistic insight into how this receptor system, with roles in embryonic and adult development, is regulated.

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Section: Discussionsupporting

confidence: 85%

Structural Basis of Neurohormone Perception by the Receptor Tyrosine Kinase Torso

et al. 2015

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“…Thus, temperature can affect ecdysone indirectly via DILP-mediated regulation of synthesis in the PG of Drosophila. Oxygen and temperature may also be integrated by the PG itself, as suggested from studies in other insects [101,102]. Interestingly, ecdysone regulates growth negatively in larval tissues in Drosophila through a fat-body relay mechanism that inhibits systemic insulin signaling [9,103].…”

Section: Neuroendocrine Signaling Hubs Integrate Developmental and Enmentioning

confidence: 97%

Metabolism and growth adaptation to environmental conditions in Drosophila

Kaburagi

Texada

Halberg

et al. 2020

Cell. Mol. Life Sci.

106

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Organisms adapt to changing environments by adjusting their development, metabolism, and behavior to improve their chances of survival and reproduction. To achieve such flexibility, organisms must be able to sense and respond to changes in external environmental conditions and their internal state. Metabolic adaptation in response to altered nutrient availability is key to maintaining energy homeostasis and sustaining developmental growth. Furthermore, environmental variables exert major influences on growth and final adult body size in animals. This developmental plasticity depends on adaptive responses to internal state and external cues that are essential for developmental processes. Genetic studies have shown that the fruit fly Drosophila, similarly to mammals, regulates its metabolism, growth, and behavior in response to the environment through several key hormones including insulin, peptides with glucagon-like function, and steroid hormones. Here we review emerging evidence showing that various environmental cues and internal conditions are sensed in different organs that, via inter-organ communication, relay information to neuroendocrine centers that control insulin and steroid signaling. This review focuses on endocrine regulation of development, metabolism, and behavior in Drosophila, highlighting recent advances in the role of the neuroendocrine system as a signaling hub that integrates environmental inputs and drives adaptive responses.

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“…Information about temperature and oxygen might also be integrated directly by the PG to affect CW. In other insects, reports indicate that ecdysone production is inhibited PG-autonomously and PTTH-independently by hypoxia ( DeLalio et al 2015 ) and lower temperatures mimicking the overwintering phase ( Meola and Adkisson 1977 ). Another interesting possibility is that these factors may modulate CW through effects on PTTH release.…”

Section: Body-size Controlmentioning

confidence: 99%

Regulation of Body Size and Growth Control

Texada¹,

Kaburagi²,

Rewitz³

2020

Genetics

120

146

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The control of body and organ growth is essential for the development of adults with proper size and proportions, which is important for survival and reproduction. In animals, adult body size is determined by the rate and duration of juvenile growth, which are influenced by the environment. In nutrient-scarce environments in which more time is needed for growth, the juvenile growth period can be extended by delaying maturation, whereas juvenile development is rapidly completed in nutrient-rich conditions. This flexibility requires the integration of environmental cues with developmental signals that govern internal checkpoints to ensure that maturation does not begin until sufficient tissue growth has occurred to reach a proper adult size. The Target of Rapamycin (TOR) pathway is the primary cell-autonomous nutrient sensor, while circulating hormones such as steroids and insulin-like growth factors are the main systemic regulators of growth and maturation in animals. We discuss recent findings in Drosophila melanogaster showing that cell-autonomous environment and growth-sensing mechanisms, involving TOR and other growth-regulatory pathways, that converge on insulin and steroid relay centers are responsible for adjusting systemic growth, and development, in response to external and internal conditions. In addition to this, proper organ growth is also monitored and coordinated with whole-body growth and the timing of maturation through modulation of steroid signaling. This coordination involves interorgan communication mediated by Drosophila insulin-like peptide 8 in response to tissue growth status. Together, these multiple nutritional and developmental cues feed into neuroendocrine hubs controlling insulin and steroid signaling, serving as checkpoints at which developmental progression toward maturation can be delayed. This review focuses on these mechanisms by which external and internal conditions can modulate developmental growth and ensure proper adult body size, and highlights the conserved architecture of this system, which has made Drosophila a prime model for understanding the coordination of growth and maturation in animals.

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Direct effects of hypoxia and nitric oxide on ecdysone secretion by insect prothoracic glands

Cited by 13 publications

References 73 publications

Structural Basis of Neurohormone Perception by the Receptor Tyrosine Kinase Torso

Structural Basis of Neurohormone Perception by the Receptor Tyrosine Kinase Torso

Metabolism and growth adaptation to environmental conditions in Drosophila

Regulation of Body Size and Growth Control

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