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NKG2A complexed with CD94 defines a novel inhibitory natural killer cell receptor.

Brooks AG, Posch PE, Scorzelli CJ, Borrego F, Coligan JE - J. Exp. Med. (1997)

Bottom Line: CD94 has recently been shown to be a 26-kD protein covalently associated with an unidentified 43-kD protein(s).Cell surface expression of NKG2A is dependent on the association with CD94 as glycosylation patterns characteristic of mature proteins are found only in NKG2A that is associated with CD94.Similar motifs are found on Ly49 and killer cell inhibitory receptors, which also transmit negative signals to NK cells.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Structure, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA.

ABSTRACT
CD94 is a C-type lectin expressed by natural killer (NK) cells and a subset of T cells. Blocking studies using anti-CD94 mAbs have suggested that it is a receptor for human leukocyte antigen class I molecules. CD94 has recently been shown to be a 26-kD protein covalently associated with an unidentified 43-kD protein(s). This report shows that NKG2A, a 43-kD protein, is covalently associated with CD94 on the surface of NK cells. Cell surface expression of NKG2A is dependent on the association with CD94 as glycosylation patterns characteristic of mature proteins are found only in NKG2A that is associated with CD94. Analysis of NK cell clones showed that NKG2A was expressed in all NK cell clones whose CD16-dependent killing was inhibited by cross-linking CD94. The induction of an inhibitory signal is consistent with the presence of two immunoreceptor tyrosine-based inhibitory motifs (V/LXYXXL) on the cytoplasmic domain of NKG2A. Similar motifs are found on Ly49 and killer cell inhibitory receptors, which also transmit negative signals to NK cells.

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NKG2A is covalently associated with CD94. Lysates from either Jurkat, YT or NK-92 cells, together with anti-CD94 or control (antiLy49) immunoprecipitates (IP) from NK-92 were separated by SDS-PAGE  under reducing or non-reducing conditions and analyzed by Western blot  with anti-NKG2A peptide-specific Ab.
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Figure 1: NKG2A is covalently associated with CD94. Lysates from either Jurkat, YT or NK-92 cells, together with anti-CD94 or control (antiLy49) immunoprecipitates (IP) from NK-92 were separated by SDS-PAGE under reducing or non-reducing conditions and analyzed by Western blot with anti-NKG2A peptide-specific Ab.

Mentions: We wanted to determine whether NKG2A was associated with CD94. Initially, three cell lines NK-92, YT and Jurkat were assessed for NKG2A expression by Western blot. Analysis with anti-NKG2A peptide Ab showed that no NKG2A reactive proteins could be detected in Jurkat cells (Fig. 1). Under reducing conditions, proteins with molecular masses of 40–45 kD and ∼35 kD could be detected in NK-92 and ∼40 kD and ∼35 kD in YT. Under nonreducing conditions, the major species detected in YT cells had a molecular mass of ∼40 kD similar to that observed under reducing conditions whereas in NK-92 cell lysates the major species had a molecular mass of ∼70 kD. A 35-kD protein with similar mobility to that observed under reduced conditions was again detected in both NK-92 and YT cell lysates. These data indicate that NKG2A is covalently associated with another protein which is present in NK-92 but absent in YT. Unlike NK-92, YT does not express CD94, as assessed by flow cytometry (data not shown), which suggested that CD94 could be the heterodimer partner of NKG2A.


NKG2A complexed with CD94 defines a novel inhibitory natural killer cell receptor.

Brooks AG, Posch PE, Scorzelli CJ, Borrego F, Coligan JE - J. Exp. Med. (1997)

NKG2A is covalently associated with CD94. Lysates from either Jurkat, YT or NK-92 cells, together with anti-CD94 or control (antiLy49) immunoprecipitates (IP) from NK-92 were separated by SDS-PAGE  under reducing or non-reducing conditions and analyzed by Western blot  with anti-NKG2A peptide-specific Ab.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196137&req=5

Figure 1: NKG2A is covalently associated with CD94. Lysates from either Jurkat, YT or NK-92 cells, together with anti-CD94 or control (antiLy49) immunoprecipitates (IP) from NK-92 were separated by SDS-PAGE under reducing or non-reducing conditions and analyzed by Western blot with anti-NKG2A peptide-specific Ab.
Mentions: We wanted to determine whether NKG2A was associated with CD94. Initially, three cell lines NK-92, YT and Jurkat were assessed for NKG2A expression by Western blot. Analysis with anti-NKG2A peptide Ab showed that no NKG2A reactive proteins could be detected in Jurkat cells (Fig. 1). Under reducing conditions, proteins with molecular masses of 40–45 kD and ∼35 kD could be detected in NK-92 and ∼40 kD and ∼35 kD in YT. Under nonreducing conditions, the major species detected in YT cells had a molecular mass of ∼40 kD similar to that observed under reducing conditions whereas in NK-92 cell lysates the major species had a molecular mass of ∼70 kD. A 35-kD protein with similar mobility to that observed under reduced conditions was again detected in both NK-92 and YT cell lysates. These data indicate that NKG2A is covalently associated with another protein which is present in NK-92 but absent in YT. Unlike NK-92, YT does not express CD94, as assessed by flow cytometry (data not shown), which suggested that CD94 could be the heterodimer partner of NKG2A.

Bottom Line: CD94 has recently been shown to be a 26-kD protein covalently associated with an unidentified 43-kD protein(s).Cell surface expression of NKG2A is dependent on the association with CD94 as glycosylation patterns characteristic of mature proteins are found only in NKG2A that is associated with CD94.Similar motifs are found on Ly49 and killer cell inhibitory receptors, which also transmit negative signals to NK cells.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Molecular Structure, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland 20852, USA.

ABSTRACT
CD94 is a C-type lectin expressed by natural killer (NK) cells and a subset of T cells. Blocking studies using anti-CD94 mAbs have suggested that it is a receptor for human leukocyte antigen class I molecules. CD94 has recently been shown to be a 26-kD protein covalently associated with an unidentified 43-kD protein(s). This report shows that NKG2A, a 43-kD protein, is covalently associated with CD94 on the surface of NK cells. Cell surface expression of NKG2A is dependent on the association with CD94 as glycosylation patterns characteristic of mature proteins are found only in NKG2A that is associated with CD94. Analysis of NK cell clones showed that NKG2A was expressed in all NK cell clones whose CD16-dependent killing was inhibited by cross-linking CD94. The induction of an inhibitory signal is consistent with the presence of two immunoreceptor tyrosine-based inhibitory motifs (V/LXYXXL) on the cytoplasmic domain of NKG2A. Similar motifs are found on Ly49 and killer cell inhibitory receptors, which also transmit negative signals to NK cells.

Show MeSH
Related in: MedlinePlus