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Insulin activates protein kinase B, inhibits glycogen synthase kinase‐3 and activates glycogen synthase by rapamycin‐insensitive pathways in skeletal muscle and adipose tissue
Author(s) -
Cross Darren A.E.,
Watt Peter W.,
Shaw Morag,
van der Kaay Jeroen,
Downes C.Peter,
Holder Julie C.,
Cohen Philip
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00240-8
Subject(s) - glycogen synthase , gsk 3 , protein kinase b , medicine , endocrinology , insulin , glycogen , gsk3b , glycogenesis , chemistry , insulin receptor , phosphorylase kinase , glycogen branching enzyme , glycogen phosphorylase , biology , kinase , signal transduction , biochemistry , insulin resistance
Insulin stimulated protein kinase Bα (PKBα) more than 10‐fold and decreased glycogen synthase kinase‐3 (GSK3) activity by 50±10% in skeletal muscle and adipocytes. Rapamycin did not prevent the activation of PKB, inhibition of GSK3 or stimulation of glycogen synthase up to 5 min. Thus rapamycin‐insensitive pathways mediate the acute effect of insulin on glycogen synthase in the major insulin‐responsive tissues. The small and very transient effects of EGF on phosphatidylinositol (3,4,5)P 3 PKBα and GSK3 in adipocytes, compared to the strong and sustained effects of insulin, explains why EGF does not stimulate glucose uptake or glycogen synthesis in adipocytes