RRC ID 54433
著者 Zahoor MK, Poidevin M, Lecerf C, Garrido D, Montagne J.
タイトル A Drosophila genetic screen for suppressors of S6kinase-dependent growth identifies the F-box subunit Archipelago/FBXW7.
ジャーナル Mol Genet Genomics
Abstract This study was designed to identify novel negative regulators of the Drosophila S6kinase (dS6K). S6K is a downstream effector of the growth-regulatory complex mTORC1 (mechanistic-Target-of-Rapamycin complex 1). Nutrients activate mTORC1, which in turn induces the phosphorylation of S6K to promote cell growth, whereas fasting represses mTORC1 activity. Here, we screened 11,000 RNA-interfering (RNAi) lines and retained those that enhanced a dS6K-dependent growth phenotype. Since RNAi induces gene knockdown, enhanced tissue growth supports the idea that the targeted gene acts as a growth suppressor. To validate the resulting candidate genes, we monitored dS6K phosphorylation and protein levels in double-stranded RNAi-treated S2 cells. We identified novel dS6K negative regulators, including gene products implicated in basal cellular functions, suggesting that feedback inputs modulate mTORC1/dS6K signaling. We also identified Archipelago (Ago), the Drosophila homologue of FBXW7, which is an E3-ubiquitin-ligase subunit that loads ubiquitin units onto target substrates for proteasome-mediated degradation. Despite a previous report showing an interaction between Ago/FBXW7 and dS6K in a yeast two-hybrid assay and the presence of an Ago/FBXW7-consensus motif in the dS6K polypeptide, we could not see a direct interaction in immunoprecipitation assay. Nevertheless, we observed that loss-of-ago/fbxw7 in larvae resulted in an increase in dS6K protein levels, but no change in the levels of phosphorylated dS6K or dS6K transcripts, suggesting that Ago/FBXW7 indirectly controls dS6K translation or stability. Through the identification of novel negative regulators of the downstream target, dS6K, our study may help deciphering the underlying mechanisms driving deregulations of mTORC1, which underlies several human diseases.
巻・号 294(3)
ページ 573-582
公開日 2019-6-1
DOI 10.1007/s00438-018-01529-5
PII 10.1007/s00438-018-01529-5
PMID 30656413
MeSH Animals Animals, Genetically Modified Cell Line Drosophila Proteins / genetics* Drosophila Proteins / metabolism Drosophila melanogaster / genetics* Drosophila melanogaster / growth & development Drosophila melanogaster / metabolism F-Box Proteins / genetics* F-Box Proteins / metabolism F-Box-WD Repeat-Containing Protein 7 / genetics F-Box-WD Repeat-Containing Protein 7 / metabolism Gene Expression Regulation, Developmental Larva / genetics Larva / growth & development Larva / metabolism Mechanistic Target of Rapamycin Complex 1 / genetics Mechanistic Target of Rapamycin Complex 1 / metabolism Phosphorylation RNA Interference Ribosomal Protein S6 Kinases / genetics* Ribosomal Protein S6 Kinases / metabolism Signal Transduction / genetics
IF 2.879
引用数 2
リソース情報
ショウジョウバエ 6147R-1 6975R-8 1283R-1 1283R-2 2165R-2 4581R-1 4581R-3 6947R-3 7447R-1 8034R-1 8318R-3 8349R-1 10139R-2 15010R-2 15010R-3 31826Ra-4