NCR2

• OMIM: 604 531
• UniProt: O95944

NKp44 ( gene: NCR2 ), synonym CD336, is a receptor protein which is localized in the plasma membrane of activated NK cells. It belongs to the family of natural cytotoxic receptors ( NCR) and acts in the activating ligand binding to the function of NK cell.

Physiology

NK cells recognize different target structures with this receptor and thereby activated. In the sequence are recognized cells destroyed, the NK cell forms cytokines and initiates an adaptive immune response.

Molecular structure

Structurally, the protein consists of an extracellular V- type immunoglobulin -like domain, a transmembrane region with a characteristic lysine and a cytoplasmic domain with a functionally inactive ITIM ( immunoreceptor tyrosine -based motif activated ).

Target structures and target structures expressing cells

The endogenous ligand has not yet been characterized. NKp44 but recognizes mycobacteria (M. tuberculosis, M. avium, M. smegmatis, BCG, Nocardia foranicia ) and Pseudomonas aeruginosa, the detected structures are not known. NKp44 recognizes H5 influenza hemagglutinin. The endogenous ligand - NKp44L - is expressed on T cells; by gp41 of HIV, this expression is increased. In HIV infection, there is an increased NK cell activity; about the putative NKp44 ligand T cells are recognized and eliminated by NK cells.

Signal transduction

NKp44 binds via the transmembrane region (lysine ) non-covalently in the ITAM of DAP12 Signaltransduktionsadapters ( Karap ).

Expressing cells

NKp44 is expressed only on activated NK cells, but not on resting NK cells. A subset of γδ T cells express NKp44.