Smith K M, Wu J, Bakker A B, Phillips J H, Lanier L L
DNAX Research Institute, Palo Alto, CA 94304, USA.
J Immunol. 1998 Jul 1;161(1):7-10.
Several members of the Ly-49 receptor family inhibit NK cell-mediated lysis of targets expressing appropriate MHC class I molecules. Ly-49D and Ly-49H, two Ly-49 molecules that lack immunoreceptor tyrosine-based inhibitory motifs (ITIM) in their cytoplasmic domains, associate with mouse DAP12, a molecule that possesses an immunoreceptor tyrosine-based activation motif (ITAM). Cotransfection of either Ly-49D or Ly-49H with DAP12 induces surface expression of both Ly-49 and DAP12. The Ly-49/DAP12 complex was coimmunoprecipitated from the transfected cells, demonstrating a physical association of DAP12 with Ly-49D or Ly-49H in the plasma membrane. Stimulation of transfectants with Abs recognizing either Ly-49D or Ly-49H results in cellular activation, as assessed by induction of tyrosine phosphorylation of multiple cellular substrates.
Ly-49受体家族的几个成员可抑制自然杀伤（NK）细胞介导的对表达适当MHC I类分子的靶标的裂解作用。Ly-49D和Ly-49H是两种Ly-49分子，其胞质结构域缺乏基于免疫受体酪氨酸的抑制基序（ITIM），它们与小鼠DAP12相关联，DAP12是一种具有基于免疫受体酪氨酸的激活基序（ITAM）的分子。将Ly-49D或Ly-49H与DAP12共转染可诱导Ly-49和DAP12的表面表达。Ly-49/DAP12复合物从转染细胞中共免疫沉淀，证明DAP12与质膜中的Ly-49D或Ly-49H存在物理关联。用识别Ly-49D或Ly-49H的抗体刺激转染细胞会导致细胞活化，这可通过多种细胞底物酪氨酸磷酸化的诱导来评估。
