Reconstitution of a ligand-binding competent murine NKp30 receptor

Abstract

The activating natural cytotoxicity receptors on natural killer (NK) cells play a fundamental role in immunosurveillance of infections and cancer. Phylogenetic analyses showed that NKp30 is highly conserved in almost all jawed vertebrates and thus, represents one of the most ancient NK cell receptors. However, in contrast to other higher vertebrates, NKp30 is only a pseudogene in mouse, which contains two premature stop codons. To decipher the evolutionary role and biological function of NKp30 in mouse, we removed these premature stop codons and expressed the putative mouse NKp30 (mNKp30) protein as soluble Fc fusion construct and as full-length receptor on A5-GFP reporter cells. Interestingly, even though both NKp30 variants were expressed, maturation and targeting to the plasma membrane were impaired. Previous studies implicated that N-linked glycosylation is crucial for plasma membrane targeting and ligand binding of human NKp30. However, even though present in all other jawed vertebrates analyzed so far, these three N-linked glycosylation sites are missing in mouse NKp30. Interestingly, reconstitution of N-linked glycosylation enabled secretion of a mNKp30-Fc fusion protein which recognized a yet unknown ligand on the plasma membrane of mastocytoma cells. Based on these data, our study is the first to show expression and functional analysis of a mNKp30 protein suggesting that the mouse NKp30 pseudogene is the result of a species-specific loss of function.

ITAM‐based receptors in natural killer cells

“…Of these, only the NKp46 receptor has a homolog in mice while NKp30 is a pseudogene, and no gene has been identified for NKp44. 62,63 Unlike NKp46 and NKp30, NKp44 (NCR2) associates with DAP12 (see below). 64 NKp46 contains two extracellular immunoglobulin domains while NKp30 and NKp44 have a single Ig domain followed by a singlepass TM domain and a short cytoplasmic tail.…”

“…Humans express three NCRs, but only NKp46 ( NCR1 ) and NKp30 ( NCR3 ) associate with CD3ζ and FcRγ. Of these, only the NKp46 receptor has a homolog in mice while NKp30 is a pseudo‐gene, and no gene has been identified for NKp44 62,63 . Unlike NKp46 and NKp30, NKp44 ( NCR2 ) associates with DAP12 (see below) 64 .…”

Das neue Patientenverfügungs-Gesetz — Schadenersatzrechtliche Folgen

“…Abgesehen von der Aufklärung speziell über die medizinischen Folgen der Patientenverfügung bestehen keine zusätzlichen Verpflichtungen des Arztes im Vergleich zu einem "aktuellen" Aufklärungsgespräch. 28 Mangels zeitlicher oder sachlicher Dringlichkeit ist "Totalaufklärung" geboten, 29 was vom PatVG in § 5 Abs 1 mit "umfassender ärztlicher Aufklärung" umschrieben wird. Das Gesetz spricht nur von ärztlicher Aufklärung, ohne dass eine Spezifizierung nach ärztlichen Fachgebieten vorgenommen wird.…”