Specific inhibition of insulin receptor dephosphorylation by a synthetic dodecapeptide containing sulfotyrosyl residues as phosphotyrosyl mimetic.
Indian J Biochem Biophys
;
1997 Feb-Apr; 34(1-2): 50-5
Article
in English
| IMSEAR
| ID: sea-26401
ABSTRACT
We have synthesized a tris-sulfotyrosyl dodecapeptide (3S-peptide-I) that corresponds to the major autophosphorylation domain within the insulin receptor beta-subunit and showed that it potently inhibited insulin receptor dephosphorylation by protein tyrosine phosphatases (PTPases) in vitro. 3S-peptide-I also inhibited tyrosine dephosphorylation of a synthetic peptide by the recombinant PTPase PTP-1B, indicating that 3S-peptide-I interacts directly with PTPase, causing its inactivation. The peptide had no effect on the activity of serine/threonine phosphatases, PP-1 and PP-2A, or alkaline phosphatase. Furthermore, we found that the introduction of a N-stearyl derivative of 3S-peptide-I in CHO/HIRc cells caused a significant increase in insulin-stimulated phosphorylation of the insulin receptor. In contrast, ligand-stimulated phosphorylation of epidermal growth factor (EGF) receptor in CHO cells overexpressing EGF receptors was not affected by the presence of N-stearyl-3S-peptide-I. These data suggest that by inhibiting dephosphorylation of the insulin receptor in intact cells, 3S-peptide-I may specifically enhance insulin signalling.
Full text:
Available
Index:
IMSEAR (South-East Asia)
Main subject:
Peptide Fragments
/
Phosphorylation
/
Recombinant Proteins
/
Humans
/
Receptor, Insulin
/
Signal Transduction
/
Amino Acid Sequence
/
Cricetinae
/
Protein Tyrosine Phosphatases
/
CHO Cells
Language:
English
Journal:
Indian J Biochem Biophys
Year:
1997
Type:
Article
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