Protein phosphatase 2A is the main phosphatase involved in the regulation of protein kinase B in rat adipocytes.
Författare
Summary, in English
In adipocytes, protein kinase B (PKB) has been suggested to be the enzyme that phosphorylates phosphodiesterase 3B (PDE3B), a key enzyme in insulin's antilipolytic signalling pathway. In order to screen for PKB phosphatases, adipocyte homogenates were fractionated using ion-exchange chromatography and analysed for PKB phosphatase activities. PKB phosphatase activity eluted as one main peak, which coeluted with serine/threonine phosphatases (PP)2A. In addition, adipocytes were incubated with inhibitors of PP. Incubation of adipocytes with 1 microM okadaic acid inhibited PP2A by 75% and PP1 activity by only 17%, while 1 microM tautomycin inhibited PP1 activity by 54% and PP2A by only 7%. Okadaic acid, but not tautomycin, induced the activation of both PKBalpha and PKBbeta. Finally, PP2A subunits were found in several subcellular compartments, including plasma membranes (PM) where the phosphorylation of PKB is thought to occur. In summary, our results suggest that PP2A is the principal phosphatase that dephosphorylates PKB in adipocytes.
Publiceringsår
2002
Språk
Engelska
Sidor
231-238
Publikation/Tidskrift/Serie
Cellular Signalling
Volym
14
Issue
3
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
Elsevier
Ämne
- Microbiology
Nyckelord
- Animal
- Phosphorylation
- Adipocytes/cytology/drug effects/enzymology
- Antibiotics
- Antifungal/pharmacology
- Cells
- Cultured
- Enzyme Inhibitors/pharmacology
- Phosphoprotein Phosphatase/antagonists & inhibitors/*metabolism
- Okadaic Acid/pharmacology
- Rats
- Subcellular Fractions
- Support
- Non-U.S. Gov't
- Proto-Oncogene Proteins/*metabolism
Status
Published
Forskningsgrupp
- Insulin Signal Transduction
ISBN/ISSN/Övrigt
- ISSN: 1873-3913