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Novel mechanisms of the regulation of Protein kinase B in adipocytes; implications for Protein kinase A, Epac, Phosphodiesterases 3 and 4.

Zmuda-Trzebiatowska, Emilia LU ; Manganiello, Vincent and Degerman, Eva LU (2007) In Cellular Signalling 19(1). p.81-86
Abstract
Crosstalk between insulin and cAMP signalling pathways has a great impact on adipocyte metabolism. Whilst Protein kinase B (PKB) is a pivotal mediator of insulin action, in some cells regulation of PKB by cAMP has also been demonstrated. Here we provide evidence that, in a phosphatidyl inositol 3-kinase dependent manner, beta 3-adrenergic stimulation (using CL316243) in adipocytes induces PKB phosphorylation in the absence of insulin and also potentiates insulin-induced phosphorylation of PKB. Interestingly, insulin- and CL316243-induced PKB phosphorylation was found to be inhibited by pools of cAMP controlled by PDE3B and PDE4 (mainly in the context of insulin), whereas a cAMP pool controlling protein kinase A appeared to mediate... (More)
Crosstalk between insulin and cAMP signalling pathways has a great impact on adipocyte metabolism. Whilst Protein kinase B (PKB) is a pivotal mediator of insulin action, in some cells regulation of PKB by cAMP has also been demonstrated. Here we provide evidence that, in a phosphatidyl inositol 3-kinase dependent manner, beta 3-adrenergic stimulation (using CL316243) in adipocytes induces PKB phosphorylation in the absence of insulin and also potentiates insulin-induced phosphorylation of PKB. Interestingly, insulin- and CL316243-induced PKB phosphorylation was found to be inhibited by pools of cAMP controlled by PDE3B and PDE4 (mainly in the context of insulin), whereas a cAMP pool controlling protein kinase A appeared to mediate stimulation of PKB phosphorylation (mainly in the context of CL316243). Furthermore, an Epac (exchange protein directly activated by cAMP) agonist (8-pCPT-2'-O-Me-cAMP) mimicked the effect of the PDE inhibitors, giving evidence that Epac has an inhibitory effect on PKB phosphorylation in adipocytes. Further, we put the results obtained at the level of PKB in the context of possible downstream signalling components in the regulation of adipocyte metabolism. Thus, we found that overexpression of PKB induced lipogenesis in a PDE3B-dependent manner. Furthermore, overexpression or inhibition of PDE3B was associated with reduced or increased phosphorylation of the key lipogenic enzyme acetyl-CoA carboxylase (ACC), respectively. These PDE3B-dependent effects on ACC correlated with changes in lipogenesis. The Epac agonist, 8-pCPT-2'-O-Me-cAMP, mimicked the effect of PDE3B inhibition on ACC phosphorylation and lipogenesis. (c) 2006 Elsevier Inc. All rights reserved. (Less)
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keywords
CAMP, CROSS-TALK, GLUCOSE-UPTAKE, RAT ADIPOCYTES, ADIPOSE-TISSUE, ADENOSINE MONOPHOSPHATE, FAT-CELLS, INSULIN-INDUCED PHOSPHORYLATION, CYCLIC-NUCLEOTIDE PHOSPHODIESTERASE, ACC, lipogenesis, adipocyte, cAMP, phosphodiesterase inhibitor, insulin, PI3K, ACTIVATION
in
Cellular Signalling
volume
19
issue
1
pages
81 - 86
publisher
Elsevier
external identifiers
  • wos:000243628600009
  • scopus:33845460303
ISSN
1873-3913
DOI
10.1016/j.cellsig.2006.05.024
language
English
LU publication?
yes
id
fa574daf-cb7d-436c-a763-5443e1956e04 (old id 158984)
alternative location
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=16839743&dopt=Abstract
date added to LUP
2007-07-20 11:06:39
date last changed
2017-08-20 03:43:37
@article{fa574daf-cb7d-436c-a763-5443e1956e04,
  abstract     = {Crosstalk between insulin and cAMP signalling pathways has a great impact on adipocyte metabolism. Whilst Protein kinase B (PKB) is a pivotal mediator of insulin action, in some cells regulation of PKB by cAMP has also been demonstrated. Here we provide evidence that, in a phosphatidyl inositol 3-kinase dependent manner, beta 3-adrenergic stimulation (using CL316243) in adipocytes induces PKB phosphorylation in the absence of insulin and also potentiates insulin-induced phosphorylation of PKB. Interestingly, insulin- and CL316243-induced PKB phosphorylation was found to be inhibited by pools of cAMP controlled by PDE3B and PDE4 (mainly in the context of insulin), whereas a cAMP pool controlling protein kinase A appeared to mediate stimulation of PKB phosphorylation (mainly in the context of CL316243). Furthermore, an Epac (exchange protein directly activated by cAMP) agonist (8-pCPT-2'-O-Me-cAMP) mimicked the effect of the PDE inhibitors, giving evidence that Epac has an inhibitory effect on PKB phosphorylation in adipocytes. Further, we put the results obtained at the level of PKB in the context of possible downstream signalling components in the regulation of adipocyte metabolism. Thus, we found that overexpression of PKB induced lipogenesis in a PDE3B-dependent manner. Furthermore, overexpression or inhibition of PDE3B was associated with reduced or increased phosphorylation of the key lipogenic enzyme acetyl-CoA carboxylase (ACC), respectively. These PDE3B-dependent effects on ACC correlated with changes in lipogenesis. The Epac agonist, 8-pCPT-2'-O-Me-cAMP, mimicked the effect of PDE3B inhibition on ACC phosphorylation and lipogenesis. (c) 2006 Elsevier Inc. All rights reserved.},
  author       = {Zmuda-Trzebiatowska, Emilia and Manganiello, Vincent and Degerman, Eva},
  issn         = {1873-3913},
  keyword      = {CAMP,CROSS-TALK,GLUCOSE-UPTAKE,RAT ADIPOCYTES,ADIPOSE-TISSUE,ADENOSINE MONOPHOSPHATE,FAT-CELLS,INSULIN-INDUCED PHOSPHORYLATION,CYCLIC-NUCLEOTIDE PHOSPHODIESTERASE,ACC,lipogenesis,adipocyte,cAMP,phosphodiesterase inhibitor,insulin,PI3K,ACTIVATION},
  language     = {eng},
  number       = {1},
  pages        = {81--86},
  publisher    = {Elsevier},
  series       = {Cellular Signalling},
  title        = {Novel mechanisms of the regulation of Protein kinase B in adipocytes; implications for Protein kinase A, Epac, Phosphodiesterases 3 and 4.},
  url          = {http://dx.doi.org/10.1016/j.cellsig.2006.05.024},
  volume       = {19},
  year         = {2007},
}