Requirement for 3-phosphoinositide-dependent kinase-1 (PDK-1) in insulin-induced glucose uptake in immortalized brown adipocytes

Hiroshi Sakaue, Akihiko Nishizawa, Wataru Ogawa, Kiyoshi Teshigawara, Toshiyuki Mori, Yasuhiro Takashima, Tetsuo Noda, Masato Kasuga

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24 Citations (Scopus)


To provide insight into the physiological importance of 3-phosphoinositide-dependent kinase-1 (PDK-1) in the metabolic actions of insulin, we have generated mice that harbor a PDK-1 gene containing LoxP sites (PDK-1lox/lox mice) and established immortalized brown preadipocyte cell lines both from these animals and from wild-type mice. Exposure to appropriate hormonal inducers resulted in the differentiation of >80% of the immortalized brown preadipocytes derived from both types of mice into mature adipocytes. Introduction of the Cre recombinase with the use of adenovirus-mediated gene transfer induced a dose-dependent decrease in the abundance of PDK-1 in PDK-1lox/lox adipocytes but not in the wild-type cells. In Cre-expressing PDK-1lox/lox adipocytes in which the abundance of PDK-1 was reduced by ∼85%, the insulin-induced phosphorylation both of Akt on threonine 308 and of p70 S6 kinase on threonine-389 was markedly inhibited. The phosphorylation both of Akt on serine 473 and of p42 and p44 isoforms of mitogen-activated protein kinase induced by insulin was not affected by Cre expression, indicating that the latter specifically inhibits PDK-1-dependent signaling. Both glucose uptake and the translocation of glucose transporter 4 to the plasma membrane induced by insulin as well as glucose uptake induced by a constitutively active form of phosphoinositide 3-kinase were also greatly inhibited by Cre expression in PDK1lox/lox adipocytes. Phosphorylation of AMP-activated protein kinase and glucose uptake induced by 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) were not affected by Cre expression in PDK-1 lox/lox adipocytes. These results indicate that PDK-1 is essential for insulin-induced glucose uptake in adipocytes.

Original languageEnglish
Pages (from-to)38870-38874
Number of pages5
JournalJournal of Biological Chemistry
Issue number40
Publication statusPublished - Oct 3 2003

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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