Dephosphorylation by default, a potential mechanism for regulation of insulin receptor substrate-1/2, Akt, and ERK1/2

Rachel Zhande, Wenshuo Zhang, Yanbin Zheng, Elisha Pendleton, Yu Li, Roberto D. Polakiewicz, Jian Sun Xiao

Research output: Contribution to journalArticle

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Abstract

Protein phosphorylation is an important mechanism that controls many cellular activities. Phosphorylation of a given protein is precisely controlled by two opposing biochemical reactions catalyzed by protein kinases and protein phosphatases. How these two opposing processes are coordinated to achieve regulation of protein phosphorylation is unresolved. We have developed a novel experimental approach to directly study protein dephosphorylation in cells. We determined the kinetics of dephosphorylation of insulin receptor substrate-1/2, Akt, and ERK1/2, phosphoproteins involved in insulin receptor signaling. We found that insulin-induced ERK1/2 and Akt kinase activities were completely abolished 10 min after inhibition of the corresponding upstream kinases with PD98059 and LY294002, respectively. In parallel experiments, insulin-induced phosphorylation of Akt, ERK1/2, and insulin receptor substrate-1/2 was decreased and followed similar kinetics. Our findings suggest that these proteins are dephosphorylated by a default mechanism, presumably via constitutively active phosphatases. However, dephosphorylation of these proteins is overcome by activation of protein kinases following stimulation of the insulin receptor. We propose that, during acute insulin stimulation, the kinetics of protein phosphorylation is determined by the interplay between upstream kinase activity and dephosphorylation by default.

Original languageEnglish (US)
Pages (from-to)39071-39080
Number of pages10
JournalJournal of Biological Chemistry
Volume281
Issue number51
DOIs
StatePublished - Dec 22 2006

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Insulin Receptor Substrate Proteins
Phosphorylation
Proteins
Phosphotransferases
Insulin Receptor
Insulin
Protein Kinases
Kinetics
2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
Phosphoprotein Phosphatases
Phosphoproteins
Phosphoric Monoester Hydrolases
Chemical activation

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Dephosphorylation by default, a potential mechanism for regulation of insulin receptor substrate-1/2, Akt, and ERK1/2. / Zhande, Rachel; Zhang, Wenshuo; Zheng, Yanbin; Pendleton, Elisha; Li, Yu; Polakiewicz, Roberto D.; Xiao, Jian Sun.

In: Journal of Biological Chemistry, Vol. 281, No. 51, 22.12.2006, p. 39071-39080.

Research output: Contribution to journalArticle

Zhande, Rachel ; Zhang, Wenshuo ; Zheng, Yanbin ; Pendleton, Elisha ; Li, Yu ; Polakiewicz, Roberto D. ; Xiao, Jian Sun. / Dephosphorylation by default, a potential mechanism for regulation of insulin receptor substrate-1/2, Akt, and ERK1/2. In: Journal of Biological Chemistry. 2006 ; Vol. 281, No. 51. pp. 39071-39080.
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