Pten (phosphatase and tensin homologue gene) haploinsufficiency promotes insulin hypersensitivity
Open Access
- 29 December 2006
- journal article
- Published by Springer Science and Business Media LLC in Diabetologia
- Vol. 50 (2), 395-403
- https://doi.org/10.1007/s00125-006-0531-x
Abstract
Insulin controls glucose metabolism via multiple signalling pathways, including the phosphatidylinositol 3-kinase (PI3K) pathway in muscle and adipose tissue. The protein/lipid phosphatase Pten (phosphatase and tensin homologue deleted on chromosome 10) attenuates PI3K signalling by dephosphorylating the phosphatidylinositol 3,4,5-trisphosphate generated by PI3K. The current study was aimed at investigating the effect of haploinsufficiency for Pten on insulin-stimulated glucose uptake. Insulin sensitivity in Pten heterozygous (Pten +/−) mice was investigated in i.p. insulin challenge and glucose tolerance tests. Glucose uptake was monitored in vitro in primary cultures of myocytes from Pten +/− mice, and in vivo by positron emission tomography. The phosphorylation status of protein kinase B (PKB/Akt), a downstream signalling protein in the PI3K pathway, and glycogen synthase kinase 3β (GSK3β), a substrate of PKB/Akt, was determined by western immunoblotting. Following i.p. insulin challenge, blood glucose levels in Pten +/− mice remained depressed for up to 120 min, whereas glucose levels in wild-type mice began to recover after approximately 30 min. After glucose challenge, blood glucose returned to normal about twice as rapidly in Pten +/− mice. Enhanced glucose uptake was observed both in Pten +/− myocytes and in skeletal muscle of Pten +/− mice by PET. PKB and GSK3β phosphorylation was enhanced and prolonged in Pten +/− myocytes. Pten is a key negative regulator of insulin-stimulated glucose uptake in vitro and in vivo. The partial reduction of Pten due to Pten haploinsufficiency is enough to elicit enhanced insulin sensitivity and glucose tolerance in Pten +/− mice.This publication has 54 references indexed in Scilit:
- Turning Signals On and Off: GLUT4 Traffic in the Insulin-Signaling HighwayPhysiology, 2005
- PTEN, but Not SHIP2, Suppresses Insulin Signaling through the Phosphatidylinositol 3-Kinase/Akt Pathway in 3T3-L1 AdipocytesJournal of Biological Chemistry, 2005
- Pten Dose Dictates Cancer Progression in the ProstatePLoS Biology, 2003
- Gene Delivery to MuscleCurrent Protocols in Human Genetics, 2001
- Dependence of Insulin-Stimulated Glucose Transporter 4 Translocation on 3-Phosphoinositide-Dependent Protein Kinase-1 and Its Target Threonine-410 in the Activation Loop of Protein Kinase C-Molecular Endocrinology, 1999
- Mutation ofPten/Mmac1in mice causes neoplasia in multiple organ systemsProceedings of the National Academy of Sciences, 1999
- Effects of transiently expressed atypical (ζ, λ), conventional (α, β) and novel (δ, ε) protein kinase C isoforms on insulin-stimulated translocation of epitope-tagged GLUT4 glucose transporters in rat adipocytes: specific interchangeable effects of protein kinases C-ζ and C-λBiochemical Journal, 1999
- Negative Regulation of PKB/Akt-Dependent Cell Survival by the Tumor Suppressor PTENCell, 1998
- Identification of a candidate tumour suppressor gene, MMAC1, at chromosome 10q23.3 that is mutated in multiple advanced cancersNature Genetics, 1997
- PTEN , a Putative Protein Tyrosine Phosphatase Gene Mutated in Human Brain, Breast, and Prostate CancerScience, 1997