Functional identification of <i>Bombyx mori</i> Atg13 in autophagy

Li, Shuyan; Xu, Jing; Xu, Xianying; Ma, Wen-Ya; Tian, Ling; Li, Kang

doi:10.1002/arch.21718

Cited by 10 publications

(9 citation statements)

References 31 publications

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“…Starvation activates AMPK (AMP-activated protein kinase) in addition to the inhibition of MTOR signaling in insects, and AMPK antagonizes or coordinates with MTOR signals in regulating the phosphorylation of different proteins [ 5 , 33 , 34 , 35 ]. BmTip60 harbored an additional protein band in B. mori fat body during the larval–pupal metamorphosis ( Figure 3 A), when AMPK activity is high [ 33 ].…”

Section: Resultsmentioning

confidence: 99%

“…In addition, starvation also activates AMP-activated protein kinase (AMPK) to induce autophagy through the inhibition of MTOR activity via the phosphorylation of tuberous sclerosis complex 2 (TSC2) and raptor in mammals [ 32 , 33 ]. Similarly, starvation regulates autophagy through interaction with PI3K-MTORC1 and AMPK in D. melanogaster and B. mori , thus affecting the phosphorylation status of the Atg1-Atg13 protein complex to initiate autophagy [ 5 , 34 , 35 ].…”

Section: Introductionmentioning

confidence: 99%

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Tip60 Phosphorylation at Ser 99 Is Essential for Autophagy Induction in Bombyx mori

Zhao

et al. 2020

IJMS

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Tip60, a key histone acetyltransferase of the MYST family and member of the nuclear multimeric protein complex (NuA4), regulates the activity and stability of proteins involved in the cell cycle, DNA damage responses, autophagy, etc. However, the function and regulatory mechanism of Tip60 homolog in Bombyx mori are not elucidated. In the present study, Bombyx Tip60 (BmTip60) was functionally identified. Developmental profiles showed that the protein levels and nuclear localization of BmTip60 peaked in fat body during the larval–pupal metamorphosis when autophagy was intensive; simultaneously, the BmTip60 protein migrated to form an upper band as detected by Western blot. Interestingly, the upper band of BmTip60 was reduced by λ-phosphatase treatment, indicating that it was a phosphorylated form of BmTip60. Results showed that BmTip60 was promoted by starvation but not 20-hydroxyecdysone treatment. Transcription factor AMP-activated protein kinase (AMPK) affected by starvation was pivotal for BmTip60 protein migration. In addition, one mammalian phosphorylation site was identified in BmTip60 at Ser99, the constitutive-activation mutation of Ser99 to Asp99 but not its inactive mutation to Ala99 significantly upregulated autophagy, showing the critical role of phosphorylation at Ser99 for BmTip60-mediated autophagy. In conclusion, the starvation-AMPK axis promotes BmTip60 in B. mori, which was requisite for autophagy induction. These results reveal a regulatory mechanism of histone acetyltransferase Tip60 homologs by phosphorylation in insects, and sheds light on further related studies of acetylation regulation.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Tip60 Phosphorylation at Ser 99 Is Essential for Autophagy Induction in Bombyx mori

Zhao

et al. 2020

IJMS

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“…Atg1 is required for autophagosome initiation and is sensitive to 20E injection, Atg8 is the protein most widely used to monitor autophagy [ 71 , 72 ]. The expression of the autophagy-related genes, Atg1 and Atg8 , in the fat body at 2, 6, 12, and 24 h.p.i.20E was evaluated using qRT-PCR.…”

Section: Methodsmentioning

confidence: 99%

Transcriptome analysis reveals potential function of long non-coding RNAs in 20-hydroxyecdysone regulated autophagy in Bombyx mori

Qiao

Wang

et al. 2021

BMC Genomics

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Background 20-hydroxyecdysone (20E) plays important roles in insect molting and metamorphosis. 20E-induced autophagy has been detected during the larval–pupal transition in different insects. In Bombyx mori, autophagy is induced by 20E in the larval fat body. Long non-coding RNAs (lncRNAs) function in various biological processes in many organisms, including insects. Many lncRNAs have been reported to be potential for autophagy occurrence in mammals, but it has not been investigated in insects. Results RNA libraries from the fat body of B. mori dissected at 2 and 6 h post-injection with 20E were constructed and sequenced, and comprehensive analysis of lncRNAs and mRNAs was performed. A total of 1035 lncRNAs were identified, including 905 lincRNAs and 130 antisense lncRNAs. Compared with mRNAs, lncRNAs had longer transcript length and fewer exons. 132 lncRNAs were found differentially expressed at 2 h post injection, compared with 64 lncRNAs at 6 h post injection. Thirty differentially expressed lncRNAs were common at 2 and 6 h post-injection, and were hypothesized to be associated with the 20E response. Target gene analysis predicted 6493 lncRNA-mRNA cis pairs and 42,797 lncRNA-mRNA trans pairs. The expression profiles of LNC_000560 were highly consistent with its potential target genes, Atg4B, and RNAi of LNC_000560 significantly decreased the expression of LNC_000560 and Atg4B. These results indicated that LNC_000560 was potentially involved in the 20E-induced autophagy of the fat body by regulating Atg4B. Conclusions This study provides the genome-wide identification and functional characterization of lncRNAs associated with 20E-induced autophagy in the fat body of B. mori. LNC_000560 and its potential target gene were identified to be related to 20-regulated autophagy in B. mori. These results will be helpful for further studying the regulatory mechanisms of lncRNAs in autophagy and other biological processes in this insect model.

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“…While TmAtg3 is an E2 ubiquitin-like enzyme responsible for covalent binding of PE to the C-terminus of Atg8, Atg5 is part of the Atg12-Atg5-Atg16 complex, which regulates the formation of the Atg8-PE complex. Downregulation of Atg8 transcript also downregulating Atg3 expression in insects is suggestive of an interconnection between the two genes (72). Subsequently, Relish regulates activation of autophagy by direct or indirect stimulation of nucleation step in hemocytes and AMP production in fat body.…”

Section: Autophagic Signatures Of T Molitor In Response To the Intracellular Bacterium Listeria Monocytogenesmentioning

confidence: 96%

Autophagy in Tenebrio molitor Immunity: Conserved Antimicrobial Functions in Insect Defenses

Lee

Patnaik

et al. 2021

Front. Immunol.

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The yellow mealworm beetle (Tenebrio molitor) has been exploited as an experimental model to unravel the intricacies of cellular and humoral immunity against pathogenic infections. Studies on this insect model have provided valuable insights into the phenotypic plasticity of immune defenses against parasites and pathogens. It has thus been possible to characterize the hemocoelic defenses of T. molitor that rely on the recognition of non-self-components of pathogens by pattern recognition receptors (PRRs). The subsequent signaling cascade activating pathways such as the NF-κB controlled by Toll and IMD pathways lead to the synthesis of antimicrobial peptides (AMPs), onset of hemocyte-driven phagocytosis, and activation of the prophenoloxidase cascade regulating the process of melanization. Nevertheless, the activation of autophagy-mediated defenses of T. molitor against the facultative intracellular gram-positive bacterium Listeria monocytogenes provides clear evidence of the existence of a cross-talk between autophagy and the IMD pathway. Moreover, the identification of several autophagy-related genes (Atgs) in T. molitor transcriptome and expressed sequence tag (EST) databases has contributed to the understanding of the autophagy-signaling cascade triggered by L. monocytogenes challenge. Providing further evidence of the cross-talk hypothesis, TmRelish has been shown to be required not only for regulating the synthesis of AMPs through the PGRP-LE/IMD pathway activation but also for the expression of Atgs in T. molitor larvae following L. monocytogenes challenge. Notably, L. monocytogenes can stimulate the T. molitor innate immune system by producing molecules recognized by the multifunctional PRR (TmPGRP-LE), which stimulates intracellular activation of the IMD pathway and autophagy. Considering the conservation of autophagy components involved in combating intracellular pathogens, it will be interesting to extrapolate a dynamic cross-talk model of immune activation. This review summarizes the most significant findings on the regulation of autophagy in T. molitor during L. monocytogenes infection and on the role of the innate immunity machinery, including the NF-κB pathway, in the control of pathogenic load.

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Functional identification of Bombyx mori Atg13 in autophagy

Cited by 10 publications

References 31 publications

Tip60 Phosphorylation at Ser 99 Is Essential for Autophagy Induction in Bombyx mori

Tip60 Phosphorylation at Ser 99 Is Essential for Autophagy Induction in Bombyx mori

Transcriptome analysis reveals potential function of long non-coding RNAs in 20-hydroxyecdysone regulated autophagy in Bombyx mori

Autophagy in Tenebrio molitor Immunity: Conserved Antimicrobial Functions in Insect Defenses

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