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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
16
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pubmed:dateCreated |
1996-6-6
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pubmed:databankReference |
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pubmed:abstractText |
The cDNA encoding human brain protein phosphatase inhibitor-1 (I-1) was expressed in Escherichia coli. Following PKA phosphorylation at a threonine, recombinant human I-1 was indistinguishable from rabbit skeletal muscle I-1 as a potent and specific inhibitor of the type-1 protein serine/threonine phosphatase (PP1). N-Terminal phosphopeptides of I-1 that retained the selectivity of intact human I-1 highlighted a functional domain that mediates PP1 inhibition. Substituting alanine in place of threonine-36 eliminated I-1 phosphorylation by PKA and its phosphatase inhibitor activity. An acidic residue was substituted in place of the phosphoacceptor to produce I-1(T35D), a constitutive phosphate inhibitor. I-1(T35D) was an equally effective inhibitor of PP1 and the type-2 phosphatase, PP2A. However, CNbr digestion of I-1(T35D) yielded an N-terminal peptide that showed 100-fold increased specificity as a PP1 inhibitor. This provided new insight into a unique conformation of the phosphorylated I-1 that accounts for selective inhibition of PP1 activity. Truncation of an active I-1 phosphopeptide identified an N-terminal sequence that was reduced in addition to threonine-35 phosphorylation to inhibit PP1 activity. Biosensor studies demonstrated that PP1 bound to both Phosphorylated and dephosphorylated I-1 and suggested that distinct elements of I-1 structure accounted for PP1 binding and inhibition. Our data point to multiple interactions between the I-1 functional domain. and the PP1 catalytic subunit that define this phosphoprotein as a physiological regulator of the type-1 protein phosphatase.
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Endoribonucleases,
http://linkedlifedata.com/resource/pubmed/chemical/Enzyme Inhibitors,
http://linkedlifedata.com/resource/pubmed/chemical/Intracellular Signaling Peptides...,
http://linkedlifedata.com/resource/pubmed/chemical/Muscle Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Nerve Tissue Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/PPP1R8 protein, human,
http://linkedlifedata.com/resource/pubmed/chemical/Phosphoprotein Phosphatases,
http://linkedlifedata.com/resource/pubmed/chemical/Protein Phosphatase 1,
http://linkedlifedata.com/resource/pubmed/chemical/Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/RNA-Binding Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Recombinant Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/protein phosphatase inhibitor-1
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0006-2960
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
23
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pubmed:volume |
35
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
5220-8
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pubmed:dateRevised |
2007-11-15
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pubmed:meshHeading |
pubmed-meshheading:8611507-Amino Acid Sequence,
pubmed-meshheading:8611507-Animals,
pubmed-meshheading:8611507-Base Sequence,
pubmed-meshheading:8611507-Binding Sites,
pubmed-meshheading:8611507-Brain Chemistry,
pubmed-meshheading:8611507-Carrier Proteins,
pubmed-meshheading:8611507-Circular Dichroism,
pubmed-meshheading:8611507-Cloning, Molecular,
pubmed-meshheading:8611507-Endoribonucleases,
pubmed-meshheading:8611507-Enzyme Inhibitors,
pubmed-meshheading:8611507-Escherichia coli,
pubmed-meshheading:8611507-Humans,
pubmed-meshheading:8611507-Intracellular Signaling Peptides and Proteins,
pubmed-meshheading:8611507-Molecular Sequence Data,
pubmed-meshheading:8611507-Muscle Proteins,
pubmed-meshheading:8611507-Mutagenesis, Site-Directed,
pubmed-meshheading:8611507-Nerve Tissue Proteins,
pubmed-meshheading:8611507-Phosphoprotein Phosphatases,
pubmed-meshheading:8611507-Protein Conformation,
pubmed-meshheading:8611507-Protein Phosphatase 1,
pubmed-meshheading:8611507-Proteins,
pubmed-meshheading:8611507-RNA-Binding Proteins,
pubmed-meshheading:8611507-Rabbits,
pubmed-meshheading:8611507-Recombinant Proteins,
pubmed-meshheading:8611507-Sequence Deletion,
pubmed-meshheading:8611507-Species Specificity
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pubmed:year |
1996
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pubmed:articleTitle |
Multiple structural elements define the specificity of recombinant human inhibitor-1 as a protein phosphatase-1 inhibitor.
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pubmed:affiliation |
Department of Pharmacology, Duke University Medical Center, Durham, North Carolina 27708, USA.
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pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, Non-U.S. Gov't
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