title: LCK-phosphorylated human killer cell-inhibitory receptors recruit and activate phosphatidylinositol 3-kinase.
abstract: HLA-specific killer cell inhibitory receptors (KIR) are thought to impede natural killer (NK) and T cell activation programs through recruitment of the SH2 domain-containing tyrosine phosphatases, SHP-1 and SHP-2, to their cytoplasmic tails (CYT). To identify other SH2 domain-containing proteins that bind KIR CYT, we used the recently described yeast two-bait interaction trap and a modified version of this system, both of which permit tyrosine phosphorylation of bait proteins. Using these systems, we show that KIR CYT, once phosphorylated by the src-family tyrosine kinase LCK, additionally bind the p85alpha regulatory subunit of phosphatidylinositol (PI) 3-kinase. Furthermore, we show that in an NK cell line, NK3.3, cross-linking of KIR results in recruitment of p85alpha to KIR and activation of PI 3-kinase lipid kinase activity. One consequence of KIR coupling to PI 3-kinase is downstream activation of the antiapoptotic protein kinase AKT. Therefore, in addition to providing negative signals, KIR may also contribute positive signals for NK and T cell growth and/or survival.
authors.affiliation: The Immunology Program, Memorial Sloan-Kettering Cancer Center, Cornell University Medical Center, New York, NY 10021, USA.
authors.forename: F
authors.initials: F
authors.lastname: Marti
authors.forename: C W
authors.initials: CW
authors.lastname: Xu
authors.forename: A
authors.initials: A
authors.lastname: Selvakumar
authors.forename: R
authors.initials: R
authors.lastname: Brent
authors.forename: B
authors.initials: B
authors.lastname: Dupont
authors.forename: P D
authors.initials: PD
authors.lastname: King
mesh_terms: D002460:Cell Line; D004789:Enzyme Activation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism*; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism*; D054340:Receptors, KIR; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D018909:src Homology Domains
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011971:Receptors, Immunologic; D054340:Receptors, KIR; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; C494918:AKT1 protein, human; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human