CD69-triggered ERK activation and functions are negatively regulated by CD94/NKG2-A inhibitory receptor

Alessandra Zingoni, Gabriella Palmieri, Stefania Morrone, Marta Carretero, Miguel Lopez-Botel, Mario Piccoli, Luigi Frati, Angela Santoni

Research output: Contribution to journalArticlepeer-review


CD69 represents a functional triggering molecule on activated NK and T cells, capable of inducing cytotoxic activity and costimulating cytokine production. It belongs to the C-lectin type superfamily, and its gene maps in the NK gene complex, close to other genes coding for NK receptors. CD94/NKG2-A complex is the inhibitory receptor for the non classical MHC class I molecule HLA-E on human NK cells. To investigate CD69-initiated signal transduction pathways, and to evaluate CD94/NKG2-A interference on CD69 triggering ability, we have generated transfectants expressing both receptors in the RBL eel line. Here we report that CD69 engagement leads to the activation of extracellular signal-regulated kinase (ERK) enzymes belonging to the MAPK family, and that this event is required for CD69-mediated cell degranulation. Moreover, we show that the co-engagement of CD94/NKG2-A inhibitory receptor effectively suppresses both CD69-triggered cell degranulation in RBL transfectants, through the inhibition of ERK activation, and CD69-induced cytotoxicity in human NK cells. Thus, here we provide new information on the molecular mechanisms initiated by CD69 activation receptor, and show that CD69-initiated signaling pathways and functional activity are negatively regulated by CD94/NKG2-A inhibitory complex.

Original languageEnglish
Pages (from-to)644-651
Number of pages8
JournalEuropean Journal of Immunology
Issue number2
Publication statusPublished - 2000


  • CD69
  • Inhibitory receptor
  • NK cell
  • Signal transduction

ASJC Scopus subject areas

  • Immunology


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