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Non-T cell activation linker (NTAL): a transmembrane adaptor protein involved in immunoreceptor signaling.

Brdicka T, Imrich M, Angelisová P, Brdicková N, Horváth O, Spicka J, Hilgert I, Lusková P, Dráber P, Novák P, Engels N, Wienands J, Simeoni L, Osterreicher J, Aguado E, Malissen M, Schraven B, Horejsí V - J. Exp. Med. (2002)

Bottom Line: NTAL becomes rapidly tyrosine-phosphorylated upon cross-linking of the B cell receptor (BCR) or of high-affinity Fcgamma- and Fc epsilon -receptors of myeloid cells and then associates with the cytoplasmic signaling molecules Grb2, Sos1, Gab1, and c-Cbl.NTAL expressed in the LAT-deficient T cell line J.CaM2.5 becomes tyrosine phosphorylated and rescues activation of Erk1/2 and minimal transient elevation of cytoplasmic calcium level upon TCR/CD3 cross-linking.Thus, NTAL appears to be a structural and possibly also functional homologue of LAT in non-T cells.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic.

ABSTRACT
A key molecule necessary for activation of T lymphocytes through their antigen-specific T cell receptor (TCR) is the transmembrane adaptor protein LAT (linker for activation of T cells). Upon TCR engagement, LAT becomes rapidly tyrosine phosphorylated and then serves as a scaffold organizing a multicomponent complex that is indispensable for induction of further downstream steps of the signaling cascade. Here we describe the identification and preliminary characterization of a novel transmembrane adaptor protein that is structurally and evolutionarily related to LAT and is expressed in B lymphocytes, natural killer (NK) cells, monocytes, and mast cells but not in resting T lymphocytes. This novel transmembrane adaptor protein, termed NTAL (non-T cell activation linker) is the product of a previously identified WBSCR5 gene of so far unknown function. NTAL becomes rapidly tyrosine-phosphorylated upon cross-linking of the B cell receptor (BCR) or of high-affinity Fcgamma- and Fc epsilon -receptors of myeloid cells and then associates with the cytoplasmic signaling molecules Grb2, Sos1, Gab1, and c-Cbl. NTAL expressed in the LAT-deficient T cell line J.CaM2.5 becomes tyrosine phosphorylated and rescues activation of Erk1/2 and minimal transient elevation of cytoplasmic calcium level upon TCR/CD3 cross-linking. Thus, NTAL appears to be a structural and possibly also functional homologue of LAT in non-T cells.

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Expression of NTAL. (A) cDNA encoding human NTAL was expressed in J.CaM2.5 cells and the protein product was visualized by Western blotting of the transfectants detergent lysate as compared with Ramos cells (expressing endogenous NTAL). (B) Western blotting of the indicated subpopulations of human peripheral blood cells (immunostaining for NTAL or Erk; the latter was used as a loading control).
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fig4: Expression of NTAL. (A) cDNA encoding human NTAL was expressed in J.CaM2.5 cells and the protein product was visualized by Western blotting of the transfectants detergent lysate as compared with Ramos cells (expressing endogenous NTAL). (B) Western blotting of the indicated subpopulations of human peripheral blood cells (immunostaining for NTAL or Erk; the latter was used as a loading control).

Mentions: Based on the published cDNA sequence of human WBSCR5, a full length NTAL cDNA was obtained by PCR from human leukocyte cDNA library and subcloned into bacterial (pET-15b) or eukaryotic (pEFIRES-N) expression vectors. Rabbit polyclonal and mouse monoclonal antibodies raised to the bacterially produced major part of the cytoplasmic domain of NTAL detected a band of the appropriate size in the LAT-deficient Jurkat variant JCaM2.5 following expression of NTAL (Fig. 4 A).


Non-T cell activation linker (NTAL): a transmembrane adaptor protein involved in immunoreceptor signaling.

Brdicka T, Imrich M, Angelisová P, Brdicková N, Horváth O, Spicka J, Hilgert I, Lusková P, Dráber P, Novák P, Engels N, Wienands J, Simeoni L, Osterreicher J, Aguado E, Malissen M, Schraven B, Horejsí V - J. Exp. Med. (2002)

Expression of NTAL. (A) cDNA encoding human NTAL was expressed in J.CaM2.5 cells and the protein product was visualized by Western blotting of the transfectants detergent lysate as compared with Ramos cells (expressing endogenous NTAL). (B) Western blotting of the indicated subpopulations of human peripheral blood cells (immunostaining for NTAL or Erk; the latter was used as a loading control).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196071&req=5

fig4: Expression of NTAL. (A) cDNA encoding human NTAL was expressed in J.CaM2.5 cells and the protein product was visualized by Western blotting of the transfectants detergent lysate as compared with Ramos cells (expressing endogenous NTAL). (B) Western blotting of the indicated subpopulations of human peripheral blood cells (immunostaining for NTAL or Erk; the latter was used as a loading control).
Mentions: Based on the published cDNA sequence of human WBSCR5, a full length NTAL cDNA was obtained by PCR from human leukocyte cDNA library and subcloned into bacterial (pET-15b) or eukaryotic (pEFIRES-N) expression vectors. Rabbit polyclonal and mouse monoclonal antibodies raised to the bacterially produced major part of the cytoplasmic domain of NTAL detected a band of the appropriate size in the LAT-deficient Jurkat variant JCaM2.5 following expression of NTAL (Fig. 4 A).

Bottom Line: NTAL becomes rapidly tyrosine-phosphorylated upon cross-linking of the B cell receptor (BCR) or of high-affinity Fcgamma- and Fc epsilon -receptors of myeloid cells and then associates with the cytoplasmic signaling molecules Grb2, Sos1, Gab1, and c-Cbl.NTAL expressed in the LAT-deficient T cell line J.CaM2.5 becomes tyrosine phosphorylated and rescues activation of Erk1/2 and minimal transient elevation of cytoplasmic calcium level upon TCR/CD3 cross-linking.Thus, NTAL appears to be a structural and possibly also functional homologue of LAT in non-T cells.

View Article: PubMed Central - PubMed

Affiliation: Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic.

ABSTRACT
A key molecule necessary for activation of T lymphocytes through their antigen-specific T cell receptor (TCR) is the transmembrane adaptor protein LAT (linker for activation of T cells). Upon TCR engagement, LAT becomes rapidly tyrosine phosphorylated and then serves as a scaffold organizing a multicomponent complex that is indispensable for induction of further downstream steps of the signaling cascade. Here we describe the identification and preliminary characterization of a novel transmembrane adaptor protein that is structurally and evolutionarily related to LAT and is expressed in B lymphocytes, natural killer (NK) cells, monocytes, and mast cells but not in resting T lymphocytes. This novel transmembrane adaptor protein, termed NTAL (non-T cell activation linker) is the product of a previously identified WBSCR5 gene of so far unknown function. NTAL becomes rapidly tyrosine-phosphorylated upon cross-linking of the B cell receptor (BCR) or of high-affinity Fcgamma- and Fc epsilon -receptors of myeloid cells and then associates with the cytoplasmic signaling molecules Grb2, Sos1, Gab1, and c-Cbl. NTAL expressed in the LAT-deficient T cell line J.CaM2.5 becomes tyrosine phosphorylated and rescues activation of Erk1/2 and minimal transient elevation of cytoplasmic calcium level upon TCR/CD3 cross-linking. Thus, NTAL appears to be a structural and possibly also functional homologue of LAT in non-T cells.

Show MeSH