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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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Tissue and subcellular localization of NTAL. (A) Paraffin section of lymphoid tissue immunoperoxidase stained for NTAL; the major positive structures are germinal centers. (B) Localization of NTAL in buoyant detergent-resistant microdomains (GEMs). THP-1 cells were solubilized in the presence of 3% nonionic detergent Brij-58 or 1% laurylmaltoside (LM; a detergent known to disrupt GEMs) and subjected to sucrose density gradient ultracentrifugation; the fractions (numbered from top to bottom) were analyzed by Western blotting. (C) Biosynthetic labeling of NTAL with [3H]palmitate; NTAL immunoprecipitate was analyzed by SDS-PAGE followed by fluorography of the gel. (D) Plasma membrane localization of NTAL (green) as determined by confocal microscopy in THP-1 cells and J.CaM2.5-NTAL transfectants; nuclei are shown in red.
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fig5: Tissue and subcellular localization of NTAL. (A) Paraffin section of lymphoid tissue immunoperoxidase stained for NTAL; the major positive structures are germinal centers. (B) Localization of NTAL in buoyant detergent-resistant microdomains (GEMs). THP-1 cells were solubilized in the presence of 3% nonionic detergent Brij-58 or 1% laurylmaltoside (LM; a detergent known to disrupt GEMs) and subjected to sucrose density gradient ultracentrifugation; the fractions (numbered from top to bottom) were analyzed by Western blotting. (C) Biosynthetic labeling of NTAL with [3H]palmitate; NTAL immunoprecipitate was analyzed by SDS-PAGE followed by fluorography of the gel. (D) Plasma membrane localization of NTAL (green) as determined by confocal microscopy in THP-1 cells and J.CaM2.5-NTAL transfectants; nuclei are shown in red.

Mentions: Western blotting further demonstrated absence of NTAL in peripheral blood T cells, moderate expression in monocytes, and strong expression in peripheral blood B lymphocytes and NK cells (Fig. 4 B); NTAL is also strongly expressed in B cell lines Raji and Ramos and myeloid lines THP-1 and HL-60 but not in T cell lines HPB-ALL and Jurkat (unpublished data). Immunohistochemical staining of paraffin tissue sections revealed a particularly strong expression in germinal centers of human lymph nodes (Fig. 5 A). As expected, NTAL is mostly present in buoyant GEMs (Fig. 5 B), it can be biosynthetically labeled by 3H-palmitate (Fig. 5 C), and clearly localizes to the plasma membrane (Fig. 5 D).


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)

Tissue and subcellular localization of NTAL. (A) Paraffin section of lymphoid tissue immunoperoxidase stained for NTAL; the major positive structures are germinal centers. (B) Localization of NTAL in buoyant detergent-resistant microdomains (GEMs). THP-1 cells were solubilized in the presence of 3% nonionic detergent Brij-58 or 1% laurylmaltoside (LM; a detergent known to disrupt GEMs) and subjected to sucrose density gradient ultracentrifugation; the fractions (numbered from top to bottom) were analyzed by Western blotting. (C) Biosynthetic labeling of NTAL with [3H]palmitate; NTAL immunoprecipitate was analyzed by SDS-PAGE followed by fluorography of the gel. (D) Plasma membrane localization of NTAL (green) as determined by confocal microscopy in THP-1 cells and J.CaM2.5-NTAL transfectants; nuclei are shown in red.
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Related In: Results  -  Collection

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fig5: Tissue and subcellular localization of NTAL. (A) Paraffin section of lymphoid tissue immunoperoxidase stained for NTAL; the major positive structures are germinal centers. (B) Localization of NTAL in buoyant detergent-resistant microdomains (GEMs). THP-1 cells were solubilized in the presence of 3% nonionic detergent Brij-58 or 1% laurylmaltoside (LM; a detergent known to disrupt GEMs) and subjected to sucrose density gradient ultracentrifugation; the fractions (numbered from top to bottom) were analyzed by Western blotting. (C) Biosynthetic labeling of NTAL with [3H]palmitate; NTAL immunoprecipitate was analyzed by SDS-PAGE followed by fluorography of the gel. (D) Plasma membrane localization of NTAL (green) as determined by confocal microscopy in THP-1 cells and J.CaM2.5-NTAL transfectants; nuclei are shown in red.
Mentions: Western blotting further demonstrated absence of NTAL in peripheral blood T cells, moderate expression in monocytes, and strong expression in peripheral blood B lymphocytes and NK cells (Fig. 4 B); NTAL is also strongly expressed in B cell lines Raji and Ramos and myeloid lines THP-1 and HL-60 but not in T cell lines HPB-ALL and Jurkat (unpublished data). Immunohistochemical staining of paraffin tissue sections revealed a particularly strong expression in germinal centers of human lymph nodes (Fig. 5 A). As expected, NTAL is mostly present in buoyant GEMs (Fig. 5 B), it can be biosynthetically labeled by 3H-palmitate (Fig. 5 C), and clearly localizes to the plasma membrane (Fig. 5 D).

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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