Insect Prothoracicotropic Hormone: Evidence for Two Molecular Forms

Bollenbacher, Walter E.; Katahira, Eva J.; O’Brien, Martha A.; Gilbert, Lawrence I.; Thomas, Mark K.; Agui, Noriaki; Baumhover, A. H.

doi:10.1126/science.6732895

Cited by 121 publications

(30 citation statements)

References 7 publications

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“…The structural dissimilarity of the two hormones means that there are different receptors that mediate a similar cell response. Indeed, the prothoracicotropic glands of Manduca sexta were sensitive to the small and large prothoracicotropic hormones, as demonstrated by Bollenbacher et al [6].Although initial observations pointed to bombyxin as a prothoracicotropic hormone 171, its biological function in B. mori remained obscure [8, 91. Bombyxin titers in the hemolymph of postembryonic B. mori showed no correlation with ecdysone during molting [ 101.…”

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The Prothoracicotropic Hormone Bombyxin has Specific Receptors on Insect Ovarian Cells

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Lacy

Büllesbach

1997

European Journal of Biochemistry

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Bombyxin 11, a product of the brain of the adult silkmoth, Bombyx mori, binds to ovarian cells of three different species of lepidoptera, i.e. B. mori (silkmoth), Samia Cynthia ricini (ailanthus moth), and an ovarian cell line of Spodopteru frugiperda (Sf9) (fall armyworm). Crude Sf9 cell membrane preparations were used to show that the purported bombyxin receptor binds its ligand in a specific, saturable, and reversible manner. The dissociation constant of the bombyxin-receptor complex is 260 -C 90 pM. Quantitative binding studies and Scatchard analysis suggest that every Sf9 cell displays 20000 receptors on the surface. The cross-linked bombyxin-receptor ligand complex has an apparent molecular mass of about 300 kDa as determined by SDSIPAGE. Reduction causes the bombyxin receptor to dissociate into two subunits with molecular masses of 90 kDa and 116 kDa. The size and subunit structure of the putative bombyxin receptor on Sf9 cells show some similarities to the mammalian insulin receptor.Keywords: bombyxin ; insulin ; bombyxin receptor; structure/function relationship ; photoactivatible crosslink Bombyxin, an invertebrate developmental factor similar in structure to insulin, was isolated from the brain of the silkmoth, Bombyx mori [I, 21. Bombyxin elicits metamorphosis in brain extirpated dormant pupae of the saturniid moth, Sumia Cynthia ricini [3], by acting on the prothoracic gland to stimulate the synthesis and release of ecdysone, the steroid hormone that causes molting and metamorphosis. This effect is ascribed to two structurally unrelated prothoracicotropic hormones, the smaller of which was later named bombyxin, while the larger one (30 kDa) retained the name prothoracicotropic hormone [4, 51. The structural dissimilarity of the two hormones means that there are different receptors that mediate a similar cell response. Indeed, the prothoracicotropic glands of Manduca sexta were sensitive to the small and large prothoracicotropic hormones, as demonstrated by Bollenbacher et al. [6].Although initial observations pointed to bombyxin as a prothoracicotropic hormone 171, its biological function in B. mori remained obscure [8, 91. Bombyxin titers in the hemolymph of postembryonic B. mori showed no correlation with ecdysone during molting [ 101. Furthermore, applications of physiological concentrations of bombyxin to brain extirpated dormant B. mori were ineffective in inducing metamorphosis [3].Based on the hypothesis that a structural relationship may indicate functional similarity, the insulin-like bombyxin has been suspected to have an effect on the blood sugar of insects, for instance in the metabolism of trehalose [Ill. Bombyxin was detected in the ovaries of the silkmoth [I21 and significantly higher levels of bombyxin were found in the hemolymph of the female [lo]. This observation suggests a role for bombyxin similar to that of the mammalian ovarian hormone relaxin, another member of the insulin family. It seems possible that bombyxin is involved in the ovarian development [13] of several specie...

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confidence: 77%

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The Prothoracicotropic Hormone Bombyxin has Specific Receptors on Insect Ovarian Cells

Fullbright

Lacy

Büllesbach

1997

European Journal of Biochemistry

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“…In Lepidoptera, prothoracicotropic hormones (PTTH) are synthesized by neurosecretory cells of the CNS and act on the PG, thereby initiating a transductory cascade, which results in the up-regulation of ecdysteroid synthesis from its precursor cholesterol (4). PTTH activity has been found in brain extracts of several insect species like the lepidoptera Bombyx mori (5) and Manduca sexta (6); however, we are only beginning to identify the components of the transductory cascade.…”

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The Drosophila gene Start1 : A putative cholesterol transporter and key regulator of ecdysteroid synthesis

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Gierl

Vollborn

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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“…The brain of S. cynthia ricini contains two different classes of molecules with prothoracicotropic activity, big PTTH (about 35 kDa) and small PTTH (about 4 kDa), 33) as in the case of the tobacco hornworm Manduca sexta. 37) Bioassay results indicated that the SBRP molecules are S. cynthia ricini small PTTH. On the other hand, the putative S. cynthia ricini big PTTH, which is homologous to B. mori PTTH, shows 200 to 1,000-fold higher prothoracicotropic activity than SBRP-A1 and -B1 on a molar basis.…”

Section: Samia Bombyxin-related Peptides (Sbrps)mentioning

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Studies of the Structure-Activity Relationships of Peptides and Proteins Involved in Growth and Development Based on Their Three-Dimensional Structures

Nagata¹

2010

Bioscience, Biotechnology, and Biochemistry

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Peptides and proteins with similar amino acid sequences can have different biological functions. Knowledge of their three-dimensional molecular structures is critically important in identifying their functional determinants. In this review, I describe the results of our and other groups' structure-based functional characterization of insect insulin-like peptides, a crustacean hyperglycemic hormone-family peptide, a mammalian epidermal growth factor-family protein, and an intracellular signaling domain that recognizes proline-rich sequence.

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Insect Prothoracicotropic Hormone: Evidence for Two Molecular Forms

Cited by 121 publications

References 7 publications

The Prothoracicotropic Hormone Bombyxin has Specific Receptors on Insect Ovarian Cells

The Prothoracicotropic Hormone Bombyxin has Specific Receptors on Insect Ovarian Cells

The Drosophila gene Start1 : A putative cholesterol transporter and key regulator of ecdysteroid synthesis

Studies of the Structure-Activity Relationships of Peptides and Proteins Involved in Growth and Development Based on Their Three-Dimensional Structures

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