Inhibition of the activity of protein tyrosine phosphate 1C by its SH2 domains
- PMID: 7504950
- DOI: 10.1021/bi00212a006
Inhibition of the activity of protein tyrosine phosphate 1C by its SH2 domains
Abstract
Full-length protein tyrosine phosphatase 1C (PTP1C), the catalytic domain of PTP1C (delta PTP1C), and the N-terminal SH2 domain truncated PTP1C (delta NPTP1C) were overexpressed in Escherichia coli and purified to near homogeneity. Various phosphorylated states of the synthetic phosphotyrosyl peptide TRDIYETDYYRK (IRP), corresponding to the major insulin receptor autophosphorylation sites, were used as substrates for the PTPs. There was no indication for selective dephosphorylation of any of the three phosphotyrosyl residues from the triphosphotyrosyl IRP. Kinetic studies were carried out using all seven different phosphotyrosyl IRPs. Saturation kinetics were observed for PTP1C using the triphosphotyrosyl IRP only. In contrast, for delta PTP1C, saturation was achieved for all seven phosphotyrosyl IRPs. The best substrate for delta PTP1C was the triphosphotyrosyl IRP possessing a Km of approximately 1.6 microM, about 3-4-fold lower than either the mono- or diphosphotyrosyl IRPs. However, in contrast to delta PTP1C, PTP1C had a 22-fold lower affinity for triphosphotyrosyl IRP. Furthermore, deletion of a single N-terminal SH2 domain increased the affinity of the enzyme for the triphosphotyrosyl IRP to a value similar to that obtained with delta PTP1C. The pH optima for all three enzyme constructs were very similar and could not account for the observed change in substrate affinity between the three enzymes. These results suggest that the SH2 domain of PTP1C exerts an inhibitory effect on its PTP activity.
Similar articles
-
Regulation of protein tyrosine phosphatase 1C: opposing effects of the two src homology 2 domains.Protein Eng. 1995 Dec;8(12):1309-16. doi: 10.1093/protein/8.12.1309. Protein Eng. 1995. PMID: 8869644
-
Intramolecular regulation of protein tyrosine phosphatase SH-PTP1: a new function for Src homology 2 domains.Biochemistry. 1994 Dec 27;33(51):15483-93. doi: 10.1021/bi00255a030. Biochemistry. 1994. PMID: 7528537
-
Phosphorylation and identification of a major tyrosine phosphorylation site in protein tyrosine phosphatase 1C.J Biol Chem. 1994 Jul 29;269(30):19585-9. J Biol Chem. 1994. PMID: 7518460
-
Insulin stimulates the phosphorylation of Tyr538 and the catalytic activity of PTP1C, a protein tyrosine phosphatase with Src homology-2 domains.J Biol Chem. 1994 Apr 22;269(16):12220-8. J Biol Chem. 1994. PMID: 7512963
-
'Zip codes' direct intracellular protein tyrosine phosphatases to the correct cellular 'address'.Trends Biochem Sci. 1994 Apr;19(4):151-5. doi: 10.1016/0968-0004(94)90274-7. Trends Biochem Sci. 1994. PMID: 8016862 Review.
Cited by
-
SHP-1 and SHP-2 in T cells: two phosphatases functioning at many levels.Immunol Rev. 2009 Mar;228(1):342-59. doi: 10.1111/j.1600-065X.2008.00760.x. Immunol Rev. 2009. PMID: 19290938 Free PMC article. Review.
-
Identification of a cytoplasmic, phorbol ester-inducible isoform of protein tyrosine phosphatase epsilon.Proc Natl Acad Sci U S A. 1995 Dec 19;92(26):12235-9. doi: 10.1073/pnas.92.26.12235. Proc Natl Acad Sci U S A. 1995. PMID: 8618876 Free PMC article.
-
Differential functions of the two Src homology 2 domains in protein tyrosine phosphatase SH-PTP1.Proc Natl Acad Sci U S A. 1996 Feb 6;93(3):1141-5. doi: 10.1073/pnas.93.3.1141. Proc Natl Acad Sci U S A. 1996. PMID: 8577729 Free PMC article.
-
src homology 2 domain-containing tyrosine phosphatase SHP-1 controls the development of allergic airway inflammation.J Clin Invest. 2003 Jan;111(1):109-19. doi: 10.1172/JCI15719. J Clin Invest. 2003. PMID: 12511594 Free PMC article.
-
Tyrosine phosphorylation of an SH2-containing protein tyrosine phosphatase is coupled to platelet thrombin receptor via a pertussis toxin-sensitive heterotrimeric G-protein.EMBO J. 1995 Jun 1;14(11):2519-26. doi: 10.1002/j.1460-2075.1995.tb07249.x. EMBO J. 1995. PMID: 7781604 Free PMC article.