| First Author | Kim GH | Year | 2012 |
| Journal | Biochem J | Volume | 447 |
| Issue | 3 | Pages | 437-47 |
| PubMed ID | 22861055 | Mgi Jnum | J:191304 |
| Mgi Id | MGI:5461427 | Doi | 10.1042/BJ20120861 |
| Citation | Kim GH, et al. (2012) Regulation of hepatic insulin sensitivity by activating signal co-integrator-2. Biochem J 447(3):437-47 |
| abstractText | ASC-2 (activating signal co-integrator-2, also known as AIB3 and NCoA6) is a transcriptional co-activator and regulates insulin secretion and beta-cell survival. The present study was performed to elucidate the role of ASC-2 in the regulation of insulin sensitivity. Although islet cells from 10-week-old ASC-2+/- mice secreted less insulin than wild-type islets, there was no significant difference in glucose tolerance between ASC-2+/- and wild-type mice. However, ASC-2+/- mice did show increased insulin sensitivity compared with wild-type mice in insulin tolerance tests. Consistently, the levels of phosphorylated Akt were higher in ASC-2+/- hepatocytes than in wild-type hepatocytes after insulin treatment. Moreover, decreases in phosphoenol pyruvate carboxykinase mRNA in refed mice were more prominent in ASC-2+/- livers than in wild-type livers. Interestingly, the expression levels of SOCS1 (suppressor of cytokine signalling 1) and SOCS3, well-known insulin signalling inhibitors, were decreased in ASC-2+/- hepatocytes and increased in ASC-2-overexpressing hepatocytes. Furthermore, ASC-2 was recruited to the promoter region of SOCS1 and potentiated the transcription by SREBP-1c (sterol-regulatory-element-binding protein-1c). This transcription-activating function of ASC-2 was diminished by mutations of SREBP-1c-binding sites in the SOCS1 promoter. Taken together, these results suggest that ASC-2 negatively affects hepatic insulin sensitivity, at least in part, through induction of the insulin signalling inhibitors SOCS1 and SOCS3. |
