Reaction participants Show >> << Hide
- Name help_outline GTP Identifier CHEBI:37565 (Beilstein: 5211792) help_outline Charge -4 Formula C10H12N5O14P3 InChIKeyhelp_outline XKMLYUALXHKNFT-UUOKFMHZSA-J SMILEShelp_outline Nc1nc2n(cnc2c(=O)[nH]1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])(=O)OP([O-])([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 85 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
L-seryl-[protein]
Identifier
RHEA-COMP:9863
Reactive part
help_outline
- Name help_outline L-serine residue Identifier CHEBI:29999 Charge 0 Formula C3H5NO2 SMILEShelp_outline C([C@H](CO)N*)(=O)* 2D coordinates Mol file for the small molecule Search links Involved in 73 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline GDP Identifier CHEBI:58189 Charge -3 Formula C10H12N5O11P2 InChIKeyhelp_outline QGWNDRXFNXRZMB-UUOKFMHZSA-K SMILEShelp_outline Nc1nc2n(cnc2c(=O)[nH]1)[C@@H]1O[C@H](COP([O-])(=O)OP([O-])([O-])=O)[C@@H](O)[C@H]1O 2D coordinates Mol file for the small molecule Search links Involved in 169 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,176 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
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Namehelp_outline
O-phospho-L-seryl-[protein]
Identifier
RHEA-COMP:11604
Reactive part
help_outline
- Name help_outline O-phospho-L-serine residue Identifier CHEBI:83421 Charge -2 Formula C3H4NO5P SMILEShelp_outline [O-]P([O-])(=O)OC[C@H](N-*)C(-*)=O 2D coordinates Mol file for the small molecule Search links Involved in 25 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
| RHEA:64020 | RHEA:64021 | RHEA:64022 | RHEA:64023 | |
|---|---|---|---|---|
| Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
| UniProtKB help_outline |
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| Gene Ontology help_outline |
Publications
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The gluconeogenic enzyme PCK1 phosphorylates INSIG1/2 for lipogenesis.
Xu D., Wang Z., Xia Y., Shao F., Xia W., Wei Y., Li X., Qian X., Lee J.H., Du L., Zheng Y., Lv G., Leu J.S., Wang H., Xing D., Liang T., Hung M.C., Lu Z.
Cancer cells increase lipogenesis for their proliferation and the activation of sterol regulatory element-binding proteins (SREBPs) has a central role in this process. SREBPs are inhibited by a complex composed of INSIG proteins, SREBP cleavage-activating protein (SCAP) and sterols in the endoplas ... >> More
Cancer cells increase lipogenesis for their proliferation and the activation of sterol regulatory element-binding proteins (SREBPs) has a central role in this process. SREBPs are inhibited by a complex composed of INSIG proteins, SREBP cleavage-activating protein (SCAP) and sterols in the endoplasmic reticulum. Regulation of the interaction between INSIG proteins and SCAP by sterol levels is critical for the dissociation of the SCAP-SREBP complex from the endoplasmic reticulum and the activation of SREBPs<sup>1,2</sup>. However, whether this protein interaction is regulated by a mechanism other than the abundance of sterol-and in particular, whether oncogenic signalling has a role-is unclear. Here we show that activated AKT in human hepatocellular carcinoma (HCC) cells phosphorylates cytosolic phosphoenolpyruvate carboxykinase 1 (PCK1), the rate-limiting enzyme in gluconeogenesis, at Ser90. Phosphorylated PCK1 translocates to the endoplasmic reticulum, where it uses GTP as a phosphate donor to phosphorylate INSIG1 at Ser207 and INSIG2 at Ser151. This phosphorylation reduces the binding of sterols to INSIG1 and INSIG2 and disrupts the interaction between INSIG proteins and SCAP, leading to the translocation of the SCAP-SREBP complex to the Golgi apparatus, the activation of SREBP proteins (SREBP1 or SREBP2) and the transcription of downstream lipogenesis-related genes, proliferation of tumour cells, and tumorigenesis in mice. In addition, phosphorylation of PCK1 at Ser90, INSIG1 at Ser207 and INSIG2 at Ser151 is not only positively correlated with the nuclear accumulation of SREBP1 in samples from patients with HCC, but also associated with poor HCC prognosis. Our findings highlight the importance of the protein kinase activity of PCK1 in the activation of SREBPs, lipogenesis and the development of HCC. << Less