NCR3

NKp30 ( gene: NCR3 ), synonym CD337, is a receptor protein which is localized in the cell membrane of natural killer cells in all higher mammals. NKp30 contributes to the ability of the killer cells to distinguish friend from foe ( cell ) and corresponding to curb or ramp up the activity of the killer cell. People with a specific change in NCR3 gene show increased susceptibility to malaria.

NKp30 is one of three known natural cytotoxic receptors.

Physiology

NK cells recognize with this receptor different (see above) target cells, are activated and destroy target cells. This will, for example, Cancer cells and eliminates intracellular pathogens infected cells.

Interestingly, the interaction of NK cells with Dendritzellen; latter secrete exosomes with the target structure BAT3 and BAT3 expressing on their cell surface; Result is an activation of NK cells which produce cytokine by the differentiation of iDCs to mDCs Dendritzellen of direct cytotoxicity and by reducing the number of non- differentiated iDC. The so- differentiated mDC are now induce TH1 - typical adaptive immune responses.

Molecular structure

Extracellular ( 120 aa, V -type immunoglobulin domain like ), transmembrane region (19 AS, an arginine, cf ITAM binding ), cytoplasmic (33 AS).

Target structures

  • A first target antigen is BAT3, this is an essential for the regulation of apoptosis protein whose function is still largely unknown.
  • Malaria -infected red blood cells, recognizes DBL- 1alpha peptide of the malaria protein PfEMP1 ..
  • PP65 cytomegalovirus binds ( blocking) NKp30.

Targets expressing cells

  • Almost all of the tested cells and cell lines express NKp30 -binding structures, both in a cellular compartment which ae corresponds to early endosomes, as well as on the plasma membrane.
  • Dendritzellen ( immature and mature mDCs iDC ) secrete exosomes, which is on BAT3 bound.

Signal transduction

NKp30 binds CD3ζ, via its ITAM motif, the activation of the small tyrosine kinase syk, including by the activation of the NFkB system via NIK. Consequences are NK proliferation, NK cytotoxicity and cytokine production, eg TNF and IFN.

Expressing cells

Almost exclusively NK cells in all stages of activation.

Protein isoform Human Genome Organisation Exosome (vesicle) CD3 (immunology) Interferon Blood (journal) Immunity (journal)
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