Disease relevance of NKTR

• Using immunoprecipitation and Western blotting, we found that at least three cytoplasmic host cell proteins, designated p80, p104, and p140, become tyrosine phosphorylated within 5-10 min after exposure to HSV-1 or HSV-2 [1].
• These results strongly suggest that p104 is an adhesion factor in L. monocytogenes and possibly in other Listeria species and is involved in adhesion to intestinal cells [2].

High impact information on NKTR

• Using short term culture of fresh human or mouse NK cells, antisense NK-TR-treated NK cells demonstrated strong selective reduction of NK cytotoxicity [3].
• The natural killer tumor recognition (NK-TR) protein has been shown to be a necessary component for the killing of NK-sensitive and virus-infected targets by the rat RNK-16 cell line [3].
• Expression of the NK-TR gene is required for NK-like activity in human T cells [4].
• The isomerase activity of the NK-TR cyclophilin homolog has been determined to be relatively insensitive to inhibition by the immunosuppressive drug cyclosporin A, with an IC50 value of 770 nM as compared to 19 nM for human cyclophilin [5].
• The boundaries of exons 6-8 and the alternate splicing events in this region are identical to those previously described for the human NKTR gene [6].

Biological context of NKTR

• We report here the discovery of two sites of alternate splicing in the 5' region of the NK-TR mRNA [7].
• IL-2 regulates the expression of the NK-TR gene via an alternate RNA splicing mechanism [7].
• One of these events caused a frameshift in the open reading frame by splicing in a 28 bp exon within the cyclophilin coding region, resulting in the premature termination of the NK-TR protein [7].
• On the other hand, nuclear localization and DNA binding activity were preserved in the mutated protein. p104 was immunoprecipitable with four separate polyclonal antibodies recognizing different epitopes of the RB polypeptide, suggesting the presence of most exons in their correct reading frame [8].
• This study investigated the role of a L. monocytogenes cell-surface protein of 104 kDa (p104) in adhesion to human intestinal enterocyte-like Caco-2 cell lines by transposon (Tn916) mutagenesis and a p104-specific monoclonal antibody (MAb-H7) [2].

Anatomical context of NKTR

• We have recently isolated and characterized human and mouse genes of a putative natural killer (NK) cell tumour-recognition protein (NK-TR) that is specifically expressed in NK cells [7].
• In this study, we used rabbit antibodies directed against synthetic peptides corresponding to amino acids 476-497 of the NK-TR protein, to examine the expression of the NK-TR antigen in freshly purified human lymphocytes [9].

Associations of NKTR with chemical compounds

• We have constructed a soluble bacterial fusion protein between the cyclophilin-homologous domain of the NK-TR molecule and glutathione S-transferase (GST) to test for the presence of peptidylprolyl cis-trans-isomerase and chaperone activities and for cyclosporin A binding [5].

Analytical, diagnostic and therapeutic context of NKTR

• The immunoreactivity of our peptide antibodies in immunoprecipitation showed that the NK-TR-related protein expressed in purified T cells is similar to that expressed in NK cells in terms of its electrophoretic mobility [9].
• Northern blot analysis of the mRNA species transcribed in human lymphocytes revealed abundant expression of NK-TR-specific mRNA species in purified T cells [9].

References