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Mechanism of inhibition of PP2A activity and abnormal hyperphosphorylation of tau by I2(PP2A)/SET.

ABSTRACT: Protein phosphatase-2A (PP2A) activity, which is compromised in Alzheimer disease brain, is regulated by two endogenous inhibitors, one of them being I(2)(PP2A), a 277 amino acid long protein also known as SET. Here we report that both the amino terminal fragment (I(2NTF); aa 1-175) and the carboxy terminal fragment (I(2CTF); aa 176-277) of I(2)(PP2A) inhibit PP2A by binding to its catalytic subunit PP2Ac and cause hyperphosphorylation of tau. The C-terminal acidic region in I(2CTF) and Val 92 in I(2NTF) are essential for their association with PP2Ac and inhibition of the phosphatase activity.

SUBMITTER: Arnaud L

PROVIDER: S-EPMC3181127 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature

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Mechanism of inhibition of PP2A activity and abnormal hyperphosphorylation of tau by I2(PP2A)/SET.

Arnaud Lisette L Chen She S Liu Fei F Li Bin B Khatoon Sabiha S Grundke-Iqbal Inge I Iqbal Khalid K

FEBS letters 20110728 17

Protein phosphatase-2A (PP2A) activity, which is compromised in Alzheimer disease brain, is regulated by two endogenous inhibitors, one of them being I(2)(PP2A), a 277 amino acid long protein also known as SET. Here we report that both the amino terminal fragment (I(2NTF); aa 1-175) and the carboxy terminal fragment (I(2CTF); aa 176-277) of I(2)(PP2A) inhibit PP2A by binding to its catalytic subunit PP2Ac and cause hyperphosphorylation of tau. The C-terminal acidic region in I(2CTF) and Val 92 i ...[more]

PMID: 21806989

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