Insulin signaling through Akt/protein kinase B analyzed by small interfering RNA-mediated gene silencing
UMass Chan Affiliations
Program in Molecular MedicineDocument Type
Journal ArticlePublication Date
2003-06-17Keywords
1-Phosphatidylinositol 3-Kinase3T3 Cells
Adipocytes
Animals
Biological Transport
Blotting, Western
Cells, Cultured
Deoxyglucose
Electroporation
Fibroblasts
*Gene Silencing
Glucose
Humans
Insulin
Mice
Microscopy, Fluorescence
Phosphorylation
Plasmids
Protein-Serine-Threonine Kinases
Proto-Oncogene Proteins
Proto-Oncogene Proteins c-akt
RNA, Small Interfering
*Signal Transduction
Time Factors
Life Sciences
Medicine and Health Sciences
Metadata
Show full item recordAbstract
Glucose homeostasis is controlled by insulin in part through the translocation of intracellular glucose transporter 4 to the plasma membrane in muscle and fat cells. Akt/protein kinase B downstream of phosphatidylinositol 3-kinase has been implicated in this insulin-signaling pathway, but results with a variety of reagents including Akt1-/- and Akt2-/- mice have been equivocal. Here we report the application of small interfering RNA-directed gene silencing to deplete both Akt1 and Akt2 in cultured 3T3-L1 adipocytes. Loss of Akt1 alone slightly impaired insulin-mediated hexose transport activity but had no detectable effect on glycogen synthase kinase (GSK)-3 phosphorylation. In contrast, depletion of Akt2 alone by 70% inhibited approximately half of the insulin responsiveness. Combined depletions of Akt1 plus Akt2 in these cells even more markedly attenuated insulin action on glucose transporter 4 movements, hexose transport activity, and GSK-3 phosphorylation. These data demonstrate a primary role of Akt2 in insulin signaling, significant functional redundancy of Akt1 and Akt2 isoforms in this pathway, and an absolute requirement of Akt protein kinases for regulation of glucose transport and GSK-3 in cultured adipocytes.Source
Proc Natl Acad Sci U S A. 2003 Jun 24;100(13):7569-74. Epub 2003 Jun 13. Link to article on publisher's site
DOI
10.1073/pnas.1332633100Permanent Link to this Item
http://hdl.handle.net/20.500.14038/38940PubMed ID
12808134Related Resources
ae974a485f413a2113503eed53cd6c53
10.1073/pnas.1332633100