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Andrzej Galat

Bio: Andrzej Galat is an academic researcher from Yale University. The author has contributed to research in topics: FKBP & Cyclophilin. The author has an hindex of 1, co-authored 1 publications receiving 1257 citations.

Papers
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Journal ArticleDOI
26 Oct 1989-Nature
TL;DR: The FKBP and cyclophilin appear to be members of an emerging class of novel proteins that regulate T cell activation and other metabolic processes, perhaps by the recognition (and possibly the isomerization) of proline-containing epitopes in target proteins.
Abstract: THE structurally novel macrolide FK506 (refs 1,2) has recently been demonstrated to have potent immunosuppressive activity3–7 at concentrations several hundredfold lower than cyclosporin A (CsA). Cyclosporin A, a cyclic peptide, has found widespread clinical use in the prevention of graft rejection following bone marrow and organ transplantation8. The mechanisms of immunosuppression mediated by FK506 and CsA appear to be remarkably similar, suggesting that these unrelated structures act on a common receptor or on similar molecular targets, perhaps the CsA receptor, cyclophilin9–11, which has recently been shown by Fischer etal.12 and Takahashi etal.13 to have cis–trans peptidyl-prolyl isomerase activity. We have prepared an FK506 affinity matrix and purified a binding protein for FK506 from bovine thymus and from human spleen. This FK506-binding protein (FKBP) has a relative molecular mass (Mr) of ∼14,000(14K), a pi of 8.8–8.9, and does not cross-react with antisera against cyclophilin. The first 40 N-terminal residues of the bovine and 16 residues of the human FKBP were determined; the 16-residue fragments are identical to each other and unrelated to any known sequences. This protein catalyses the cis–trans isomerization of the proline amide in a tetrapeptide substrate and FK506 inhibits the action of this new isomerase. The FKBP and cyclophilin appear to be members of an emerging class of novel proteins that regulate T cell activation and other metabolic processes, perhaps by the recognition (and possibly the isomerization) of proline-containing epitopes in target proteins.

1,295 citations


Cited by
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Journal ArticleDOI
23 Aug 1991-Cell
TL;DR: The results suggest that calcineurin is involved in a common step associated with T cell receptor and IgE receptor signaling pathways and that cyclophilin and FKBP mediate the actions of CsA and Fk506 by forming drug-dependent complexes with and altering the activity of calcineURin-calmodulin.

3,968 citations

Journal ArticleDOI
TL;DR: Recent findings that indicate CsA and FK506 operate as prodrugs are reviewed: they bind endogenous intracellular receptors, the immunophilins, and the resulting complex targets the protein phosphatase, calcineurin, to exert the immunosuppressive effect.

2,032 citations

Journal ArticleDOI
23 Aug 1991-Science
TL;DR: Nonallelic noncomplementation between FPR1, TOR1, and TOR2 alleles suggests that the products of these genes may interact as subunits of a protein complex that may mediate nuclear entry of signals required for progression through the cell cycle.
Abstract: FK506 and rapamycin are related immunosuppressive compounds that block helper T cell activation by interfering with signal transduction. In vitro, both drugs bind and inhibit the FK506-binding protein (FKBP) proline rotamase. Saccharomyces cerevisiae cells treated with rapamycin irreversibly arrested in the G1 phase of the cell cycle. An FKBP-rapamycin complex is concluded to be the toxic agent because (i) strains that lack FKBP proline rotamase, encoded by FPR1, were viable and fully resistant to rapamycin and (ii) FK506 antagonized rapamycin toxicity in vivo. Mutations that conferred rapamycin resistance altered conserved residues in FKBP that are critical for drug binding. Two genes other than FPR1, named TOR1 and TOR2, that participate in rapamycin toxicity were identified. Nonallelic noncomplementation between FPR1, TOR1, and TOR2 alleles suggests that the products of these genes may interact as subunits of a protein complex. Such a complex may mediate nuclear entry of signals required for progression through the cell cycle.

1,887 citations

Journal ArticleDOI
15 Jul 1994-Cell
TL;DR: It is proposed that RAFT1 is the direct target of FKBP12-rapamycin and a mammalian homolog of the TOR proteins, which were originally identified by mutations that confer rapamycin resistance in yeast.

1,472 citations