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Suppression of gluconeogenic gene transcription by SIK1-induced ubiquitination and degradation of CRTC1
- Source :
- Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms. 1861:211-223
- Publication Year :
- 2018
- Publisher :
- Elsevier BV, 2018.
-
Abstract
- CRTCs are a group of three transcriptional coactivators required for CREB-dependent transcription. CREB and CRTCs are critically involved in the regulation of various biological processes such as cell proliferation, metabolism, learning and memory. However, whether CRTC1 efficiently induces gluconeogenic gene expression and how CRTC1 is regulated by upstream kinase SIK1 remain to be understood. In this work, we demonstrated SIK1-induced phosphorylation, ubiquitination and degradation of CRTC1 in the context of the regulation of gluconeogenesis. CRTC1 protein was destabilized by SIK1 but not SIK2 or SIK3. This effect was likely mediated by phosphorylation at S155, S167, S188 and S346 residues of CRTC1 followed by K48-linked polyubiquitination and proteasomal degradation. Expression of gluconeogenic genes such as that coding for phosphoenolpyruvate carboxykinase was stimulated by CRTC1, but suppressed by SIK1. Depletion of CRTC1 protein also blocked forskolin-induced gluconeogenic gene expression, knockdown or pharmaceutical inhibition of SIK1 had the opposite effect. Finally, SIK1-induced ubiquitination of CRTC1 was mediated by RFWD2 ubiquitin ligase at a site not equivalent to K628 in CRTC2. Taken together, our work reveals a regulatory circuit in which SIK1 suppresses gluconeogenic gene transcription by inducing ubiquitination and degradation of CRTC1. Our findings have implications in the development of new antihyperglycemic agents.
- Subjects :
- 0301 basic medicine
Proteasome Endopeptidase Complex
Transcription, Genetic
Ubiquitin-Protein Ligases
Biophysics
Protein Serine-Threonine Kinases
CREB
Biochemistry
03 medical and health sciences
Ubiquitin
Structural Biology
Transcription (biology)
Gene expression
Serine
Genetics
Humans
Protein Kinase Inhibitors
Molecular Biology
Gene knockdown
biology
Kinase
Chemistry
Gluconeogenesis
Ubiquitination
Hep G2 Cells
Ubiquitin ligase
CRTC2
Cell biology
HEK293 Cells
030104 developmental biology
Gene Knockdown Techniques
Mutation
Proteolysis
biology.protein
Phosphoenolpyruvate Carboxykinase (ATP)
Transcription Factors
Subjects
Details
- ISSN :
- 18749399
- Volume :
- 1861
- Database :
- OpenAIRE
- Journal :
- Biochimica et Biophysica Acta (BBA) - Gene Regulatory Mechanisms
- Accession number :
- edsair.doi.dedup.....a8670466aac7f862471e60828424f593