Casein Kinase 1 Regulates Sterol Regulatory Element-binding Protein (SREBP) to Control Sterol Homeostasis

[Sterol regulatory element binding protein (SREBP)].

Sterol regulatory element-binding protein (SREBP)-1-mediated lipogenesis is involved in cell senescence.

Increased cell mass is one of the characteristics of senescent cells, but this event has not been clearly defined. When subcellular organellar mass was estimated with organelle-specific fluorescence dyes, we observed that most membranous organelles progressively increase in mass during cell senescence. This increase was accompanied by an increase in membrane lipids and augmented expression of l...

Sterol regulatory element binding proteins (SREBP)-1a and SREBP-2 are linked to the MAP-kinase cascade.

The classic sterol regulatory cis element (sre-1) in the LDL receptor promoter mediates sterol regulatory element binding protein (SREBP)-binding and the effects of insulin and platelet derived growth factor (PDGF). To elucidate whether SREBP-1a and SREBP-2 play a direct role in insulin and PDGF action, stable cell lines of HepG2 deficient in either SREBP-1 or SREBP-2 were used. Transfection of...

Sterol Regulatory Element-Binding Protein 1 Is Negatively Modulated by Protein Kinase A Phosphorylation

Sterol regulatory element binding protein (SREBP) 1a and 1c are key transcription factors that regulate lipid biosynthesis in cells. We identified that Ser-338 located at the N-terminus of SREBP1a is a protein kinase A (PKA) phosphorylation site in vitro and in HepG2 cells. PKA phosphorylation of this site attenuated DNA occupancy, as revealed by ChIP assay, and the ensuing transactivation. In ...

Insulin effects on sterol regulatory-element-binding protein-1c (SREBP-1c) transcriptional activity in rat hepatocytes.

The transcription factor sterol regulatory-element-binding protein-1c (SREBP-1c) plays a major role in the effect of insulin on the transcription of hepatic genes such as glucokinase and fatty acid synthase. We show here in cultured rat hepatocytes that insulin, through activation of the phosphatidylinositol 3-kinase pathway increases the abundance of the precursor form of SREBP-1c in endoplasm...