Related Experiment Video

Updated: Jun 4, 2025

Analyzing Starvation-Induced Autophagy in the Drosophila melanogaster Larval Fat Body
06:02

Analyzing Starvation-Induced Autophagy in the Drosophila melanogaster Larval Fat Body

Published on: August 4, 2022

2.3K

The steroid hormone 20-hydroxyecdysone inhibits RAPTOR expression by repressing Hox gene transcription to induce

Tian-Wen Liu1, Can Tian1, Yan-Xue Li1

  • 1Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China.

The Journal of Biological Chemistry
|December 20, 2024
PubMed

Insights

Homeobox (HOX) proteins promote Raptor transcription, enhancing cell growth. 20-Hydroxecdysone (20E) represses HOX, leading to autophagy and reduced cell proliferation during insect metamorphosis.

Area of Science:

  • Molecular and developmental biology
  • Insect molecular biology
  • Cellular regulation

Background:

  • Regulatory-associated protein of TOR (RAPTOR) is crucial for TOR complex 1, impacting cell growth and autophagy.
  • While post-translational modifications of RAPTOR are studied, its transcriptional regulation remains largely unknown.
  • Understanding Raptor's transcriptional control is vital for insect development and physiology.

Purpose of the Study:

  • To elucidate the transcriptional regulatory mechanism of Raptor in the cotton bollworm (Helicoverpa armigera).
  • To investigate the roles of 20-Hydroxecdysone (20E) and Homeobox (HOX) proteins in regulating Raptor expression.
  • To determine the impact of Raptor regulation on insect development, autophagy, and cell proliferation.

Main Methods:

  • Analysis of Raptor expression profiles across different tissues and developmental stages (larva to pupa).
  • Gene knockdown experiments to assess the functional consequences of Raptor disruption.
  • Investigation of the regulatory interactions between 20E, HOX proteins, and the Raptor promoter using molecular techniques.

Main Results:

  • Raptor exhibits stage- and tissue-specific expression, with high levels during larval feeding and low levels during metamorphosis.
  • Raptor knockdown at the feeding stage leads to smaller pupae and increased autophagy; knockdown during metamorphosis impairs development.
  • 20E represses Raptor transcription, while HOX proteins promote it by binding to the Raptor promoter. 20E also represses HOX transcription.

Conclusions:

  • HOX proteins act as positive transcriptional regulators of Raptor, promoting cell proliferation and inhibiting autophagy.
  • 20E, through its nuclear receptor EcR, represses HOX gene transcription, consequently downregulating Raptor expression.
  • This regulatory axis involving HOX and 20E controls the balance between cell proliferation and autophagy during insect metamorphosis.
Keywords:
20-hydroxyecdysoneRAPTORautophagycell proliferationhomeobox

More Related Videos

An Ecdysone Receptor-based Singular Gene Switch for Deliberate Expression of Transgene with Robustness, Reversibility, and Negligible Leakiness06:21

An Ecdysone Receptor-based Singular Gene Switch for Deliberate Expression of Transgene with Robustness, Reversibility, and Negligible Leakiness

Published on: May 7, 2018

6.5K
Medium-scale Preparation of Drosophila Embryo Extracts for Proteomic Experiments09:16

Medium-scale Preparation of Drosophila Embryo Extracts for Proteomic Experiments

Published on: May 30, 2017

7.9K

Related Concept Videos

PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a...
3.4K
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
3.7K
Hedgehog Signaling Pathway02:33

Hedgehog Signaling Pathway

The Hedgehog gene (Hh) was first discovered due to its control of the growth of disorganized, hair-like bristles phenotype in Drosophila, much like hedgehog spines. Hh plays a crucial role in the development of organs and the maintenance of homeostasis in both invertebrates and vertebrates. However, while Drosophila has only one Hh protein, mammals have multiple functional Hedgehog proteins - Sonic (Shh), Desert (Dhh), and Indian Hedgehog (Ihh). All of these homologous proteins have adapted to...
7.3K
The Ratio of X Chromosome to Autosomes02:45

The Ratio of X Chromosome to Autosomes

In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.  
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female...
8.4K
Regulated Protein Degradation02:58

Regulated Protein Degradation

It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
7.1K
Autophagic Cell Death01:18

Autophagic Cell Death

Christian de Duve discovered “autophagy,” a process in which cellular components are engulfed by membrane-bound organelles called autophagosomes. The autophagosomes then fuse with lysosomes to digest the enclosed contents. Autophagy is generally activated in cells to prevent cell death. However, cell death is triggered when the damage is beyond repair.
Autophagy and Apoptosis
Autophagy can activate apoptosis. In normal conditions, the autophagy activating protein Beclin-1 and...
3.4K