Targeting Src homology 2 domain-containing tyrosine phosphatase (SHP-1) into lipid rafts inhibits CD3-induced T cell activation.
To study the mechanism by which protein tyrosine phosphatases (PTPs) regulate CD3-induced tyrosine phosphorylation, we investigated the distribution of PTPs in subdomains of plasma membrane. We report here that the bulk PTP activity associated with T cell membrane is present outside the lipid rafts, as determined by sucrose density gradient sedimentation. In Jurkat T cells, approximately 5--10% of Src homology 2 domain-containing tyrosine phosphatase (SHP-1) is constitutively associated with plasma membrane, and nearly 50% of SHP-2 is translocated to plasma membrane after vanadate treatment. Similar to transmembrane PTP, CD45, the membrane-associated populations of SHP-1 and SHP-2 are essentially excluded from lipid rafts, where other signaling molecules such as Lck, linker for activation of T cells, and CD3 zeta are enriched. We further demonstrated that CD3-induced tyrosine phosphorylation of these substrates is largely restricted to lipid rafts, unless PTPs are inhibited. It suggests that a restricted partition of PTPs among membrane subdomains may regulate protein tyrosine phosphorylation in T cell membrane. To test this hypothesis, we targeted SHP-1 into lipid rafts by using the N-terminal region of Lck (residues 1--14). The results indicate that the expression of Lck/SHP-1 chimera inside lipid rafts profoundly inhibits CD3-induced tyrosine phosphorylation of CD3 zeta/epsilon, IL-2 generation, and nuclear mobilization of NF-AT. Collectively, these results suggest that the exclusion of PTPs from lipid rafts may be a mechanism that potentiates TCR/CD3 activation.
Su
M W
MW
Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
Yu
C L
CL
Burakoff
S J
SJ
Jin
Y J
YJ
D017252:CD3 Complex / Q000378:metabolism / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D015536:Down-Regulation / Q000276:immunology*; D018390:Gene Targeting; D006801:Humans; D007376:Interleukin-2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D047908:Intracellular Signaling Peptides and Proteins; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000235:genetics; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000235:genetics / Q000502:physiology; D021962:Membrane Microdomains / Q000201:enzymology* / Q000276:immunology / Q000378:metabolism; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D017830:Octoxynol / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000502:physiology; D010766:Phosphorylation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000502:physiology*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D012995:Solubility; D013347:Subcellular Fractions / Q000201:enzymology / Q000378:metabolism; D013601:T-Lymphocytes / Q000201:enzymology* / Q000276:immunology* / Q000378:metabolism; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000378:metabolism; D014443:Tyrosine / Q000037:antagonists & inhibitors / Q000378:metabolism; D018909:src Homology Domains / Q000235:genetics / Q000276:immunology*
D017252:CD3 Complex; C121704:CD3 antigen, zeta chain; C115335:CD3E protein, human; D004268:DNA-Binding Proteins; D007376:Interleukin-2; D047908:Intracellular Signaling Peptides and Proteins; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010446:Peptide Fragments; D011948:Receptors, Antigen, T-Cell; D014157:Transcription Factors; D014443:Tyrosine; D017830:Octoxynol; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); 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