Analysis of insulin signalling by RNAi-based gene silencing

Q. I. Zhou, J. G. Park, Z. Y. Jiang, J. J. Holik, P. Mitra, S. Semiz, A. Guilherme, A. M. Powelka, X. Tang, J. Virbasius, M. P. Czech

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Using siRNA-mediated gene silencing in cultured adipocytes, we have dissected the insulin-signalling pathway leading to translocation of GLUT4 glucose transporters to the plasma membrane. RNAi (RNA interference)-based depletion of components in the putative TC10 pathway (CAP, CrkII and c-Cbl plus Cbl-b) or the phospholipase Cγ pathway failed to diminish insulin signalling to GLUT4. Within the phosphoinositide 3-kinase pathway, loss of the 5′-phosphatidylinositol 3,4,5-trisphosphate phosphatase SHIP2 was also without effect, whereas depletion of the 3′-phosphatase PTEN significantly enhanced insulin action. Downstream of phosphatidylinositol 3,4,5-trisphosphate and PDK1, silencing the genes encoding the protein kinases Akt1/PKBα, or CISK(SGK3) or protein kinases Cλ/ζ had little or no effect, but loss of Akt2/PKBβ significantly attenuated GLUT4 regulation by insulin. These results show that Akt2/PKBβ is the key downstream intermediate within the phosphoinositide 3-kinase pathway linked to insulin action on GLUT4 in cultured adipocytes, whereas PTEN is a potent negative regulator of this pathway.

Original languageBritish English
Pages (from-to)817-821
Number of pages5
JournalBiochemical Society Transactions
Issue number5
StatePublished - Nov 2004


  • Gene silencing
  • Glucose
  • Insulin signalling
  • Phosphoinositide 3-kinase (PI3K)
  • Phospholipase Cγ
  • Protien kinase Cλ/ζ siRNA


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