Defective T cell receptor signaling and CD8+ thymic selection in humans lacking Zap-70 kinase

Arpaia, Enrico; Shahar, Michal; Dadi, Harjit; Cohen, Amos; Roifman, Chaim M.

doi:10.1016/0092-8674(94)90368-9

Cited by 519 publications

(332 citation statements)

References 45 publications

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“…ZAP-70 appears to be essential for both differentiation and maturation of pre-T cells and activation of mature T lymphocytes. Humans lacking ZAP-70 were found to have no CD8 ϩ T cells in their thymus, and their mature peripheral blood T cells were nonresponsive to antigenic stimulation (27)(28)(29). Mice genetically engineered to be deficient in ZAP-70 are even more impaired.…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies of a rare human disease provide further support for the importance of ZAP-70 in T cell differentiation and activation. Mutations within the ZAP-70 gene that result in a lack of ZAP-70 protein give rise to a severe T cell immunodeficiency reflected by failure of the T cells to proliferate and become activated following antigen or mitogen stimulation (27)(28)(29). Thus, absence of ZAP-70 results in an inability of the TCR to couple to downstream signaling pathways.…”

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confidence: 99%

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Purification and Characterization of Human ZAP-70 Protein-tyrosine Kinase from a Baculovirus Expression System

Isakov

Wange

Watts

et al. 1996

Journal of Biological Chemistry

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The ZAP-70 protein tyrosine kinase is essential for T cell antigen receptor (TCR)-mediated signaling. The absence of ZAP-70 results in impaired differentiation of T cells and a lack of responsiveness to antigenic stimulation. In order to study the characteristics of ZAP-70 in vitro, we overexpressed an epitopically tagged human ZAP-70 in a recombinant baculovirus expression system and purified it by column chromatography. The kinase activity of purified, recombinant ZAP-70 required cation and exhibited a strong preference for Mn 2؉ over Mg 2؉ . The apparent K m of ZAP-70 for ATP was ϳ3.0 M. The activity of the recombinant ZAP-70, unlike that of the homologous protein tyrosine kinase, Syk, was not affected by binding of TCR-derived tyrosine phosphorylated immunoreceptor tyrosine-based activation motif peptides. Several proteins were tested as potential in vitro substrates of ZAP-70. Only ␣-tubulin and the cytoplasmic fragment of human erythrocyte band 3 (cfb3), which have a region of sequence identity at the phosphorylation site, proved to be good substrates, exhibiting K m values of ϳ3.3 and ϳ2.5 M, respectively ([ATP] ‫؍‬ 50 M). ␣-and ␤-Casein were poor substrates for ZAP-70, and no activity toward enolase, myelin basic protein, calmodulin, histone proteins, or angiotensin could be detected. In contrast to the T cell protein tyrosine kinase, Lck, ZAP-70 did not phosphorylate the cytoplasmic portion of the TCR chain or short peptides corresponding to the CD3⑀ or the TCR immunoreceptor tyrosinebased activation motifs. Our studies suggest that ZAP-70 exhibits a high degree of substrate specificity.Stimulation of the antigen-specific receptor on T cells (TCR) 1 initiates a cascade of biochemical events leading to activation of the mature T cell. Among the earliest biochemical events that follows TCR triggering is the activation of protein-tyrosine kinases (PTKs) resulting in a transient tyrosine phosphorylation of multiple intracellular protein substrates (reviewed in Refs. 1 and 2) including the TCR/CD3 subunits (3-5). These multiple TCR subunits lack intrinsic PTK activity; instead, they interact with and activate cytoplasmic PTKs that couple the receptor to the signaling apparatus.PTKs that have been implicated in TCR signaling include the Src family members, Fyn and Lck, and the TCR -associated-protein (ZAP-70) (reviewed in Refs. 1 and 2). Although Fyn is constitutively associated with nonpolymorphic components of TCR/CD3 subunits (6, 7), Lck is noncovalently associated with the cytoplasmic domain of the CD4 and CD8 co-receptor molecules (8, 9). Both Fyn and Lck can also directly associate with the inner leaflet of the plasma membrane via their Nterminal myristylation/palmitylation signals (10), whereas ZAP-70, which lacks this sequence, is thought to reside in the cytosol in resting cells and then becomes rapidly recruited to the TCR upon its activation and phosphorylation (11,12). Following interaction of the TCR with peptide-bound MHC molecules on the surface of antigen presenting cells, CD4 or CD8 interact ...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Purification and Characterization of Human ZAP-70 Protein-tyrosine Kinase from a Baculovirus Expression System

Isakov

Wange

Watts

et al. 1996

Journal of Biological Chemistry

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“…With the exception of one child who lacked ZAP-70 mRNA by Northern blot in whom the underlying mutation is not known (19) and another child with temperature-sensitive P80Q and M572L mutations (28), ZAP-70-deficient patients have inherited mutations within a small region of the ZAP-70 kinase domain that significantly affect both protein stability and catalytic activity. These included a 13-bp deletion resulting in a frame-shift after residue 503 and premature termination at amino acid 538 (16), two amino acid conversions, S518R (17) and A507V (27), and a splicing error that inserts LEQ into the protein after residue 541 (17,18).…”

Section: Novel Human Zap-70 Mutationmentioning

confidence: 99%

Distinct T Cell Developmental Consequences in Humans and Mice Expressing Identical Mutations in the DLAARN Motif of ZAP-70

Elder

Skoda-Smith

Kadlecek

et al. 2001

The Journal of Immunology

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The protein tyrosine kinase, ZAP-70, is pivotally involved in transduction of Ag-binding signals from the TCR required for T cell activation and development. Defects in ZAP-70 result in SCID in humans and mice. We describe an infant with SCID due to a novel ZAP-70 mutation, comparable with that which arose spontaneously in an inbred mouse colony. The patient inherited a homozygous missense mutation within the highly conserved DLAARN motif in the ZAP-70 kinase domain. Although the mutation only modestly affected protein stability, catalytic function was absent. Despite identical changes in the amino acid sequence of ZAP-70, the peripheral T cell phenotypes of our patient and affected mice are distinct. ZAP-70 deficiency in this patient, as in other humans, is characterized by abundant nonfunctional CD4+ T cells and absent CD8+ T cells. In contrast, ZAP-70-deficient mice lack both major T cell subsets. Although levels of the ZAP-70-related protein tyrosine kinase, Syk, may be sufficiently increased in human thymocytes to rescue CD4 development, survival of ZAP-70-deficient T cells in the periphery does not appear to be dependent on persistent up-regulation of Syk expression.

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“…In addition, SYK is required for the B-cell antigen receptor-mediated positive selection of immature B cells into the recirculating B-cell pool (Turner et al, 1997). Although SYK has not been linked to a human disease, defective expression of the closely related T-cell tyrosine kinase ZAP-70 has been associated with severe combined immunode®ciency (Arpaia et al, 1994;Chan et al, 1994;Elder et al, 1994;Perlmutter, 1994).…”

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confidence: 99%

Spleen tyrosine kinase (Syk) deficiency in childhood pro-B cell acute lymphoblastic leukemia

et al. 2001

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The cytoplasmic spleen tyrosine kinase (SYK) is a key regulator of signal transduction events, apoptosis and orderly cell cycle progression in B-lineage lymphoid cells. Although SYK has not been linked to a human disease, defective expression of the closely related T-cell tyrosine kinase ZAP-70 has been associated with severe combined immunode®ciency. Childhood CD19 + CD10 7 pro-B cell acute lymphoblastic leukemia (ALL) is thought to originate from B-cell precursors with a maturational arrest at the pro-B cell stage and it is associated with poor prognosis. Since lethally irradiated mice reconstituted with SYK-de®cient fetal liver-derived lymphohematopoietic progenitor cells show a block in B-cell ontogeny at the pro-B to pre-B cell transition, we examined the SYK expression pro®les of primary leukemic cells from children with pro-B cell ALL. Here we report that leukemic cells from pediatric CD19 + CD10 7 pro-B cell ALL patients (but not leukemic cells from patients with CD19 + CD10 + common pre-pre-B cell ALL) have markedly reduced SYK activity. Sequencing of the reverse transcriptase-polymerase chain reaction (RT ± PCR) products of the Syk mRNA in these pro-B leukemia cells revealed profoundly aberrant coding sequences with deletions or insertions. These mRNA species encode abnormal SYK proteins with a missing or truncated catalytic kinase domain. In contrast to pro-B leukemia cells, pre-pre-B leukemia cells from children with CD19 + CD10 + common Blineage ALL and EBV-transformed B-cell lines from healthy volunteers expressed wild-type Syk coding sequences. Examination of the genomic structure of the Syk gene by inter-exonic PCR and genomic cloning demonstrated that the deletions and insertions in the abnormal mRNA species of pro-B leukemia cells are caused by aberrant splicing resulting in either missplicing, exon skipping or inclusion of alternative exons, consistent with an abnormal posttranscriptional regulation of alternative splicing of Syk pre-mRNA. Our ®ndings link for the ®rst time speci®c molecular defects involving the Syk gene to an immunophenotypically distinct category of childhood ALL. To our knowledge, this is the ®rst discovery of a speci®c tyrosine kinase de®ciency in a human hematologic malignancy. Oncogene (2001) 20, 3969 ± 3978.

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Defective T cell receptor signaling and CD8+ thymic selection in humans lacking Zap-70 kinase

Cited by 519 publications

References 45 publications

Purification and Characterization of Human ZAP-70 Protein-tyrosine Kinase from a Baculovirus Expression System

Purification and Characterization of Human ZAP-70 Protein-tyrosine Kinase from a Baculovirus Expression System

Distinct T Cell Developmental Consequences in Humans and Mice Expressing Identical Mutations in the DLAARN Motif of ZAP-70

Spleen tyrosine kinase (Syk) deficiency in childhood pro-B cell acute lymphoblastic leukemia

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