Abstract FK506, a neutral macrolide with immunosuppressive properties, was shown to selectively and rapidly inhibit the accumulation of IL-2 mRNA, as well mRNAs other early (E) phase T cell activation genes such IL-3, IL-4, GM-CSF, TNF alpha, IFN-gamma, c-myc in activated human peripheral blood cells. The activity when compared Cyclosporin A, another immunosuppressant, 10 100x more potent its ability mRNA synthesis. FK506 inhibited Con A plus PMA, Ionomycin anti-CD3, anti-CD3 PMA Transcripts...

FK-506 inhibits Ca(2+)-dependent transcription of lymphokine genes in T cells, and thereby acts as a powerful immunosuppressant. However, its potential therapeutic applications may be seriously limited by several side effects, including nephrotoxicity neurotoxicity. At present, it is unclear whether these immunosuppressive toxic effects result from interference with related biochemical processes. known to interact FK-binding protein-12 (FKBP-12), an abundant cytosolic protein cis-trans...

In this report we have approached two questions relating to the mechanism of action cyclosporin A (CsA). First, address whether major cytosolic protein for CsA, cyclophilin, is directly involved in mediating immunosuppressive activity drug, and, particular, inhibition protein's peptidyl-prolyl cis-trans isomerase (PPIase) results murine T cell activation. Second, ask nephrotoxicity observed with CsA related PPIase-dependent pathways cells other than lymphocytes. Using a series 61 analogues,...

Interleukin (IL)-1 is a proinflammatory cytokine with pleiotropic effects in inflammation. IL-1 binding to its receptor triggers cascade of signaling events, including activation the stress-activated mitogen-activated protein (MAP) kinases, c-Jun NH2-terminal kinase (JNK) and p38 MAP kinase, as well transcription factor nuclear kappaB (NF-kappaB). results cellular responses through induction inflammatory gene products such IL-6. One earliest events rapid interaction receptor-associated IRAK...

The macrolide rapamycin (RAP) is a potent inhibitor of interleukin-2 (IL-2)-induced T-cell proliferation. Current models suggest that RAP, when complexed to its intracellular receptor, FK506-binding protein, interferes with an IL-2 receptor-coupled signaling pathway required for cell-cycle progression from G1- S-phase. Here we show RAP treatment inhibits the growth IL-2-dependent cytotoxic line, CTLL-2, in late G1-phase, just prior entry cells into In contrast, RAP-treated CTLL-2 retained...

Interleukin (IL)-18 is functionally similar to IL-12 in mediating T helper cell type 1 (Th1) response and natural killer (NK) activity but related IL-1 protein structure signaling, including recruitment of receptor–associated kinase (IRAK) the receptor activation c-Jun NH2-terminal (JNK) nuclear factor (NF)-κB. The role IRAK IL-18–induced responses was studied IRAK-deficient mice. Significant defects JNK induction partial impairment NF-κB were found Th1 cells, resulting a dramatic decrease...

Tumor necrosis factor-alpha (TNF-alpha), a cytokine secreted by activated monocytes/macrophages and T lymphocytes, has been implicated in several disease states, including rheumatoid arthritis, inflammatory bowel disease, septic shock, osteoporosis. Monocyte/macrophage production of TNF-alpha is dependent on the mitogen-activated protein kinase p38. RWJ 67657 (4-[4-(4-fluorophenyl)-1-(3-phenylpropyl)-5-(4-pyridinyl)-1H-imidazol -2-yl]-3-butyn-1-ol) inhibited release lipopolysaccharide (a...

The immunosuppressant rapamycin (RAP) is a potent inhibitor of the entry interleukin (IL)-2-stimulated T cells into S-phase. Earlier results indicated that RAP treatment arrested growth murine IL-2-dependent cell line CTLL-2 in late G1-phase. To explore further interactions with cycle control machinery cells, we examined effects on activation cyclin-dependent kinases p34cdc2 and p33cdk2 G1-phase cells. Stimulation factor-deprived IL-2 led to assembly high molecular weight complexes...

A novel macrolide antibiotic, FK-506, isolated from Streptomyces tsukubaensis, has been shown to be a potent immunosuppressive agent in vivo and vitro. FK-506 shares number of properties with the cyclic peptide, cyclosporin (CsA), although 10 100 times more this regard. These similarities suggest that both agents may share similar mechanism(s) action at biochemical level. We have identified cytoplasmic binding protein for human T cell line, JURKAT, using [3H]FK-506. The mr 12 kDa (as...

We have recently isolated an abundant cytosolic protein from human T-cells which specifically binds the immunosuppressive agent, FK-506. The FK-506-binding (FKBP) is a member of novel class proteins possessing peptidyl-prolyl cis-trans isomerase activity. These are believed to play important role in accelerating rate at fold into their native conformations. In present study, we demonstrate that FKBP not lymphoid-specific protein, but widely distributed and phylogenically conserved. FKBP,...

Earlier, we isolated eukaryotic initiation factor 2 (eIF-2)-stimulating protein (SP) as a homogeneous complex with eIF-2 (eIF-2-SP) and showed that, in the presence of Mg2+, eIF-2-SP promotes formation ternary GTP initiator methionyl tRNA (Met-tRNAi) (eIF-2-GTP-Met-tRNAi) catalytically. We now show that SP-bound exchanges (eIF-2 exchange). Furthermore, catalyzes exchange eIF-2-bound [3H]GDP unlabeled GDP or (GDP exchange) release when is formed from eIF-2-[3H]GDP, GTP, [35S]Met-tRNAi. All...

The dl331 mutant of adenovirus serotype 5 fails to produce virus-associated (VA) RNAI, and cells infected with this do not synthesize proteins efficiently at late times in infection. translational defect occurs the level polypeptide chain initiation, cell-free extracts prepared from dl331-infected exhibit observed vivo. Addition either eukaryotic initiation factor 2 (eIF-2) or guanine nucleotide exchange (GEF) these restores activity, GEF functioning more regard. These results suggest that...

The immunoregulant FK-506 potently inhibits particular calcium-associated signal transduction events that occur early during T-lymphocyte activation and IgE receptor-mediated exocytosis in mast cells. binds to a growing family of receptors termed FK-506-binding proteins (FKBPs), the most abundant being 12-kDa cytosolic receptor, FKBP12. To date, there is no formal evidence proving FKBP12 sole receptor mediating immunosuppressive effects or toxic side FK-506. Using gel filtration...

Thymopoietin (TP) was originally isolated as a 5-kDa 49-aa protein from bovine thymus in studies of the effects thymic extracts on neuromuscular transmission and subsequently observed to affect T-cell differentiation function. We now report isolation cDNA clones for three alternatively spliced mRNAs that encode distinct human TPs. Proteins encoded by these mRNAs, which we have named TP alpha (75 kDa), beta (51 gamma (39 contain identical N-terminal regions, including sequences nearly...

FK 506, a powerful immunosuppressant that blocks allograft rejection by preventing T-cell activation, binds to an 11-kDa protein called the 506-binding (FKBP). Like cyclophilin, cytosolic another immunosuppressant, cyclosporin A, FKBP possesses peptidylprolyl cis-trans isomerase activity. We have isolated genomic clone encoding yeast (FKB1). The gene encodes of 114 amino acids having calculated Mr 12,158. Disruption shows FKB1 is not essential for growth. A search translated nucleic acid...

Catalysis of ternary complex formation by the GDP exchange factor (GEF), in presence Mg2+, is blocked phosphorylation alpha subunit eukaryotic initiation 2 (eIF-2). We proposed earlier that this interferes with interaction between eIF-2 and GEF (then termed ESP). If so, inhibition should be related to extent phosphorylation. However, work other laboratories indicated fully inhibited, heme-deficient lysates only 20-40% phosphorylated. To understand nature molecular lesion eIF-2-alpha we used...