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Your search keyword '"leucine deprivation"' showing total 3 results
Start Over Descriptor "leucine deprivation" Topic biochemistry
3 results on '"leucine deprivation"'

1. FGF21 mediates the lipid metabolism response to amino acid starvation

Author

Ana Luísa De Sousa-Coelho, Joana Relat, Elayne Hondares, Albert Pérez-Martí, Francesc Ribas, Francesc Villarroya, Pedro F. Marrero, and Diego Haro

Subjects
brown adipose tissue, fibroblast growth factor 21, leucine deprivation, liver, white adipose tissue, Biochemistry, QD415-436
Abstract

Lipogenic gene expression in liver is repressed in mice upon leucine deprivation. The hormone fibroblast growth factor 21 (FGF21), which is critical to the adaptive metabolic response to starvation, is also induced under amino acid deprivation. Upon leucine deprivation, we found that FGF21 is needed to repress expression of lipogenic genes in liver and white adipose tissue, and stimulate phosphorylation of hormone-sensitive lipase in white adipose tissue. The increased expression of Ucp1 in brown adipose tissue under these circumstances is also impaired in FGF21-deficient mice. Our results demonstrate the important role of FGF21 in the regulation of lipid metabolism during amino acid starvation.

Published
2013
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2. IGFBP-1 hyperphosphorylation in response to leucine deprivation is mediated by the AAR pathway

Author

Thomas Jansson, Niyati Malkani, and Madhulika B. Gupta

Subjects
MAPK/ERK pathway, Hyperphosphorylation, Leucine deprivation, DEPTOR, Biochemistry, Article, Endocrinology, Leucine, Humans, Phosphorylation, Molecular Biology, Mechanistic target of rapamycin, HepG2 cells, PI3K/AKT/mTOR pathway, Adaptor Proteins, Signal Transducing, Sirolimus, biology, TOR Serine-Threonine Kinases, MTOR, RPTOR, Hep G2 Cells, Regulatory-Associated Protein of mTOR, AAR, Cell biology, Insulin-Like Growth Factor Binding Protein 1, Rapamycin-Insensitive Companion of mTOR Protein, biology.protein, Cancer research, IGFBP-1 phosphorylation, Carrier Proteins, Protein Processing, Post-Translational, Signal Transduction
Abstract

Insulin-like growth factor-1 (IGF-I) is the key regulator of fetal growth. IGF-I bioavailability is markedly diminished by IGF binding protein-1 (IGFBP-1) phosphorylation. Leucine deprivation strongly induces IGFBP-1 hyperphosphorylation, and plays an important role in fetal growth restriction (FGR). FGR is characterized by decreased amino acid availability, which activates the amino acid response (AAR) and inhibits the mechanistic target of rapamycin (mTOR) pathway. We investigated the role of AAR and mTOR in mediating IGFBP-1 secretion and phosphorylation in HepG2 cells in leucine deprivation. mTOR inhibition (rapamycin or raptor + rictor siRNA), or activation (DEPTOR siRNA) demonstrated a role of mTOR in leucine deprivation-induced IGFBP-1 secretion but not phosphorylation. When the AAR was blocked (U0126, or ERK/GCN2 siRNA), both IGFBP-1 secretion and hyperphosphorylation (pSer101/pSer119/pSer169) due to leucine deprivation were prevented. CK2 inhibition by TBB also attenuated IGFBP-1 phosphorylation in leucine deprivation. These results suggest that the AAR and mTOR independently regulate IGFBP-1 secretion and phosphorylation in response to decreased amino acid availability.

Published
2015

3. FGF21 mediates the lipid metabolism response to amino acid starvation

Author

Joana Relat, Ana Luísa De Sousa-Coelho, Francesc Villarroya, Diego Haro, Elayne Hondares, Albert Pérez-Martí, Pedro F. Marrero, and Francesc Ribas

Subjects
medicine.medical_specialty, FGF21, fibroblast growth factor 21, White adipose tissue, QD415-436, liver, Biochemistry, Factors de creixement, Mice, Endocrinology, white adipose tissue, Internal medicine, Brown adipose tissue, Gene expression, medicine, Animals, Humans, Ratolins, Amino Acids, leucine deprivation, Research Articles, chemistry.chemical_classification, Mice, Knockout, Lipid metabolism, brown adipose tissue, Adipose tissues, Cell Biology, Hep G2 Cells, Lipid Metabolism, Metabolisme dels lípids, Amino acid, Fibroblast Growth Factors, Teixit adipós, medicine.anatomical_structure, chemistry, Amino acids, Aminoàcids, Leucine, Growth factors, Hormone
Abstract

Lipogenic gene expression in liver is repressed in mice upon leucine deprivation. The hormone fi broblast growth factor 21 (FGF21), which is critical to the adaptive metabolic response to starvation, is also induced under amino acid deprivation. Upon leucine deprivation, we found that FGF21 is needed to repress expression of lipogenic genes in liver and white adipose tissue, and stimulate phosphorylation of hormone-sensitive lipase in white adipose tissue. The increased expression of Ucp1 in brown adipose tissue under these circumstances is also impaired in FGF21- defi cient mice. Our results demonstrate the important role of FGF21 in the regulation of lipid metabolism during amino acid starvation. ¿De Sousa-Coelho, A. L., J. Relat, E. Hondares, A. Pérez-Martí, F. Ribas, F. Villarroya, P. F. Marrero, and D. Haro. FGF21 mediates the lipid metabolism response to amino acid starvation.

Published
2013

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