title: Recruitment of SH2-containing protein tyrosine phosphatase SHP-1 to the interleukin 2 receptor; loss of SHP-1 expression in human T-lymphotropic virus type I-transformed T cells.
abstract: Interleukin 2 (IL-2) rapidly induces tyrosine phosphorylation of intracellular substrates, including the IL-2 receptor beta chain (IL-2Rbeta), Janus kinase 1 (Jak1), Jak3, signal transducer/activator of transcription proteins, and Shc, but the mechanism underlying dephosphorylation of these proteins is not known. The src homology 2 (SH2) containing tyrosine phosphatase 1 (SHP-1) is recruited by several hematopoietic surface receptors indicating that this phosphatase plays an important role as a regulator of signaling. We have found that IL-2 induces association of SHP-1 with the IL-2 receptor complex, and that once SHP-1 is recruited to the activated receptor it is able to decrease tyrosine phosphorylation of IL-2Rbeta and the associated tyrosine kinases Jak1 and Jak3. This dephosphorylation is specific as expression of a catalytically inactive form of SHP-1, or expression of the related phosphatase SHP-2 did not result in dephosphorylation of the IL-2 receptor components. Furthermore, we have found that SHP-1 expression is greatly decreased or undetectable in a number of IL-2 independent HTLV-I transformed T cell lines that exhibit constitutive Jak/signal transducer/activator of transcription activation. In HTLV-I infected T cells, down-regulation of SHP-1 expression was also found to correlate with the acquisition of IL-2 independence. These observations suggest that SHP-1 normally functions to antagonize the IL-2 signal transduction pathway and that HTLV-I infection and oncogenic transformation can lead to loss of SHP-1 expression resulting in constitutive activation of IL-2 regulated T cell responses.
authors.affiliation: DNAX Research Institute, 901 California Avenue, Palo Alto, CA 94304, USA. migone@dnax.org
authors.forename: T S
authors.initials: TS
authors.lastname: Migone
authors.forename: N A
authors.initials: NA
authors.lastname: Cacalano
authors.forename: N
authors.initials: N
authors.lastname: Taylor
authors.forename: T
authors.initials: T
authors.lastname: Yi
authors.forename: T A
authors.initials: TA
authors.lastname: Waldmann
authors.forename: J A
authors.initials: JA
authors.lastname: Johnston
mesh_terms: D002472:Cell Transformation, Viral / Q000276:immunology*; D015536:Down-Regulation; D005786:Gene Expression Regulation / Q000276:immunology*; D015368:Human T-lymphotropic virus 1; D006801:Humans; D007376:Interleukin-2 / Q000276:immunology*; D047908:Intracellular Signaling Peptides and Proteins; D010766:Phosphorylation; D054645:Protein Phosphatase 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000096:biosynthesis / Q000276:immunology*; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis / Q000276:immunology*; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000821:virology; D018909:src Homology Domains
chemical_list: D007376:Interleukin-2; D047908:Intracellular Signaling Peptides and Proteins; D015375:Receptors, Interleukin-2; D054645:Protein Phosphatase 1; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases