TOR signaling is required for amino acid stimulation of early trypsin protein synthesis in the midgut of Aedes aegypti mosquitoes

Michelle C. Brandon, James E. Pennington, Jun Isoe, Jorge Zamora, Anne Sophie Schillinger, Roger Miesfeld

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Blood meal digestion in mosquitoes occurs in two phases, an early phase that is translationally regulated, and a late phase that is transcriptionally regulated. Early trypsin is a well-characterized serine endoprotease that is representative of other early phase proteases in the midgut that are only synthesized after feeding. Since the kinase Target of Rapamycin (TOR) has been implicated as a nutrient sensor in other systems, including the mosquito fat body, we tested if TOR signaling is involved in early trypsin protein synthesis in the mosquito midgut in response to feeding. We found that ingestion of an amino acid meal by female mosquitoes induces early trypsin protein synthesis, coincident with phosphorylation of two known TOR target proteins, p70S6 kinase (S6K) and the translational repressor 4E-Binding Protein (4E-BP). Moreover, in vitro culturing of midguts from unfed mosquitoes led to amino acid-dependent phosphorylation of S6K and 4E-BP which could be blocked by treatment with rapamycin, a TOR-specific inhibitor. Lastly, by injecting mosquitoes with TOR double stranded RNA (dsRNA) or rapamycin, we demonstrated that TOR signaling was required in vivo for both phosphorylation of S6K and 4E-BP in the midgut, and for translation of early trypsin mRNA in response to amino acid feeding. It may be possible to target the TOR signaling pathway in the midgut to inhibit blood meal digestion, and thereby, decrease fecundity and the spread of mosquito borne diseases.

Original languageEnglish (US)
Pages (from-to)916-922
Number of pages7
JournalInsect Biochemistry and Molecular Biology
Volume38
Issue number10
DOIs
StatePublished - Oct 2008

Fingerprint

Aedes
Sirolimus
Aedes aegypti
Culicidae
midgut
Trypsin
trypsin
protein synthesis
Amino Acids
amino acids
Phosphorylation
binding proteins
phosphorylation
Proteins
TOR Serine-Threonine Kinases
blood meal
Meals
Carrier Proteins
digestion
mosquito-borne diseases

Keywords

  • 4E-BP
  • Blood meal metabolism
  • p70S6 Kinase
  • Rapamycin
  • RNAi
  • Translational control

ASJC Scopus subject areas

  • Insect Science
  • Biochemistry

Cite this

TOR signaling is required for amino acid stimulation of early trypsin protein synthesis in the midgut of Aedes aegypti mosquitoes. / Brandon, Michelle C.; Pennington, James E.; Isoe, Jun; Zamora, Jorge; Schillinger, Anne Sophie; Miesfeld, Roger.

In: Insect Biochemistry and Molecular Biology, Vol. 38, No. 10, 10.2008, p. 916-922.

Research output: Contribution to journalArticle

Brandon, Michelle C. ; Pennington, James E. ; Isoe, Jun ; Zamora, Jorge ; Schillinger, Anne Sophie ; Miesfeld, Roger. / TOR signaling is required for amino acid stimulation of early trypsin protein synthesis in the midgut of Aedes aegypti mosquitoes. In: Insect Biochemistry and Molecular Biology. 2008 ; Vol. 38, No. 10. pp. 916-922.
@article{ff7539c6edfa43d9b7687c289d35b7f6,
title = "TOR signaling is required for amino acid stimulation of early trypsin protein synthesis in the midgut of Aedes aegypti mosquitoes",
abstract = "Blood meal digestion in mosquitoes occurs in two phases, an early phase that is translationally regulated, and a late phase that is transcriptionally regulated. Early trypsin is a well-characterized serine endoprotease that is representative of other early phase proteases in the midgut that are only synthesized after feeding. Since the kinase Target of Rapamycin (TOR) has been implicated as a nutrient sensor in other systems, including the mosquito fat body, we tested if TOR signaling is involved in early trypsin protein synthesis in the mosquito midgut in response to feeding. We found that ingestion of an amino acid meal by female mosquitoes induces early trypsin protein synthesis, coincident with phosphorylation of two known TOR target proteins, p70S6 kinase (S6K) and the translational repressor 4E-Binding Protein (4E-BP). Moreover, in vitro culturing of midguts from unfed mosquitoes led to amino acid-dependent phosphorylation of S6K and 4E-BP which could be blocked by treatment with rapamycin, a TOR-specific inhibitor. Lastly, by injecting mosquitoes with TOR double stranded RNA (dsRNA) or rapamycin, we demonstrated that TOR signaling was required in vivo for both phosphorylation of S6K and 4E-BP in the midgut, and for translation of early trypsin mRNA in response to amino acid feeding. It may be possible to target the TOR signaling pathway in the midgut to inhibit blood meal digestion, and thereby, decrease fecundity and the spread of mosquito borne diseases.",
keywords = "4E-BP, Blood meal metabolism, p70S6 Kinase, Rapamycin, RNAi, Translational control",
author = "Brandon, {Michelle C.} and Pennington, {James E.} and Jun Isoe and Jorge Zamora and Schillinger, {Anne Sophie} and Roger Miesfeld",
year = "2008",
month = "10",
doi = "10.1016/j.ibmb.2008.07.003",
language = "English (US)",
volume = "38",
pages = "916--922",
journal = "Insect Biochemistry and Molecular Biology",
issn = "0965-1748",
publisher = "Elsevier Limited",
number = "10",

}

TY - JOUR

T1 - TOR signaling is required for amino acid stimulation of early trypsin protein synthesis in the midgut of Aedes aegypti mosquitoes

AU - Brandon, Michelle C.

AU - Pennington, James E.

AU - Isoe, Jun

AU - Zamora, Jorge

AU - Schillinger, Anne Sophie

AU - Miesfeld, Roger

PY - 2008/10

Y1 - 2008/10

N2 - Blood meal digestion in mosquitoes occurs in two phases, an early phase that is translationally regulated, and a late phase that is transcriptionally regulated. Early trypsin is a well-characterized serine endoprotease that is representative of other early phase proteases in the midgut that are only synthesized after feeding. Since the kinase Target of Rapamycin (TOR) has been implicated as a nutrient sensor in other systems, including the mosquito fat body, we tested if TOR signaling is involved in early trypsin protein synthesis in the mosquito midgut in response to feeding. We found that ingestion of an amino acid meal by female mosquitoes induces early trypsin protein synthesis, coincident with phosphorylation of two known TOR target proteins, p70S6 kinase (S6K) and the translational repressor 4E-Binding Protein (4E-BP). Moreover, in vitro culturing of midguts from unfed mosquitoes led to amino acid-dependent phosphorylation of S6K and 4E-BP which could be blocked by treatment with rapamycin, a TOR-specific inhibitor. Lastly, by injecting mosquitoes with TOR double stranded RNA (dsRNA) or rapamycin, we demonstrated that TOR signaling was required in vivo for both phosphorylation of S6K and 4E-BP in the midgut, and for translation of early trypsin mRNA in response to amino acid feeding. It may be possible to target the TOR signaling pathway in the midgut to inhibit blood meal digestion, and thereby, decrease fecundity and the spread of mosquito borne diseases.

AB - Blood meal digestion in mosquitoes occurs in two phases, an early phase that is translationally regulated, and a late phase that is transcriptionally regulated. Early trypsin is a well-characterized serine endoprotease that is representative of other early phase proteases in the midgut that are only synthesized after feeding. Since the kinase Target of Rapamycin (TOR) has been implicated as a nutrient sensor in other systems, including the mosquito fat body, we tested if TOR signaling is involved in early trypsin protein synthesis in the mosquito midgut in response to feeding. We found that ingestion of an amino acid meal by female mosquitoes induces early trypsin protein synthesis, coincident with phosphorylation of two known TOR target proteins, p70S6 kinase (S6K) and the translational repressor 4E-Binding Protein (4E-BP). Moreover, in vitro culturing of midguts from unfed mosquitoes led to amino acid-dependent phosphorylation of S6K and 4E-BP which could be blocked by treatment with rapamycin, a TOR-specific inhibitor. Lastly, by injecting mosquitoes with TOR double stranded RNA (dsRNA) or rapamycin, we demonstrated that TOR signaling was required in vivo for both phosphorylation of S6K and 4E-BP in the midgut, and for translation of early trypsin mRNA in response to amino acid feeding. It may be possible to target the TOR signaling pathway in the midgut to inhibit blood meal digestion, and thereby, decrease fecundity and the spread of mosquito borne diseases.

KW - 4E-BP

KW - Blood meal metabolism

KW - p70S6 Kinase

KW - Rapamycin

KW - RNAi

KW - Translational control

UR - http://www.scopus.com/inward/record.url?scp=50849126062&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=50849126062&partnerID=8YFLogxK

U2 - 10.1016/j.ibmb.2008.07.003

DO - 10.1016/j.ibmb.2008.07.003

M3 - Article

VL - 38

SP - 916

EP - 922

JO - Insect Biochemistry and Molecular Biology

JF - Insect Biochemistry and Molecular Biology

SN - 0965-1748

IS - 10

ER -