TFEB, a basic helix-loop-helix transcription factor, is a master regulator of autophagy, lysosome biogenesis and lipid catabolism. Compared to posttranslational regulation of TFEB, the regulation of mRNA stability remains relatively uncharacterized. In this study, we identified the mRNA-binding protein THOC4 as a novel regulator of TFEB. In mammalian cells, siRNA-mediated knockdown of THOC4 decreased the level of TFEB protein to a greater extent than other bHLH transcription factors. THOC4 bound to mRNA and stabilized it after transcription by maintaining poly(A) tail length. We further found that this mode of regulation was conserved in and was essential for TFEB-mediated lipid breakdown, which becomes over-represented during prolonged starvation. Taken together, our findings reveal the presence of an additional layer of TFEB regulation by THOC4 and provide novel insights into the function of TFEB in mediating autophagy and lipid metabolism.
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http://dx.doi.org/10.1242/jcs.248203 | DOI Listing |
Curr Opin Gastroenterol
January 2025
Department of Nutrition Sciences.
Purpose Of Review: Metabolic dysfunction-associated steatotic liver disease (MASLD) is present in 25-35% of individuals in the United States. The purpose of this review is to provide the contextual framework for hepatic ketogenesis in MASLD and to spotlight recent advances that have improved our understanding of the mechanisms that drive its development and progression.
Recent Findings: Traditionally, hepatic ketogenesis has only been considered metabolically during prolonged fasting/starvation or with carbohydrate deplete ketogenic diets where ketones provide important alternative energy sources.
Insect Sci
January 2025
Guizhou Provincial Key Laboratory for Agricultural Pest Management of the Mountainous Region, Institute of Entomology, Guizhou University, Guiyang, China.
Feeding and molting are particularly important physiological processes for insects, and it has been reported that neuropeptides are involved in the nervous regulation of these 2 processes. Sulfakinin (SK) is an important neuropeptide that is widely distributed among insects and plays a pivotal role in regulating feeding, courtship, aggression, and locomotion. In this study, we investigated the involvement of SK in feeding and molting on a highly notorious pest insect, the fall armyworm, Spodoptera frugiperda.
View Article and Find Full Text PDFRes Sq
December 2024
Nephrogenetics unit, Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany.
Similar to the mammalian hepatocytes, oenocytes accumulate fat during fasting, but it is unclear how they communicate with the fat body, the major lipid source. Using a modified protocol for prolonged starvation, we show that knockdown (KD) of the sole delta 9 desaturase, Desat1 (SCD in mammals), specifically in oenocytes leads to more saturated lipids in the hemolymph and reduced triacylglycerol (TAG) storage in the fat body. Additionally, oenocytes with KD exhibited an accumulation of lipoproteins and actin filaments at the cortex, which decreased lipoproteins in the hemolymph.
View Article and Find Full Text PDFInsect Mol Biol
December 2024
School of Life Sciences, Suzhou Medical College of Soochow University, Suzhou, China.
Starvation can induce autophagy and apoptosis in intestinal cells. To elucidate the underlying mechanisms, we investigated autophagy and apoptosis in the midgut of the model insect, silkworm (Bombyx mori), focusing on calcium homeostasis. The results indicated that the body weight of silkworms decreased, along with damage to the morphology of their digestive tracts and midguts after starvation treatment.
View Article and Find Full Text PDFPLoS Biol
December 2024
Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.
Starvation, which is associated with inactivation of the growth-promoting TOR complex 1 (TORC1), is a strong environmental signal for cell differentiation. In the fission yeast Schizosaccharomyces pombe, nitrogen starvation has distinct physiological consequences depending on the presence of mating partners. In their absence, cells enter quiescence, and TORC1 inactivation prolongs their life.
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