1b5l
OVINE INTERFERON TAUOVINE INTERFERON TAU
Structural highlights
FunctionIFNT1_SHEEP Paracrine hormone primarily responsible for maternal recognition of pregnancy. Interacts with endometrial receptors, probably type I interferon receptors, and blocks estrogen receptor expression, preventing the estrogen-induced increase in oxytocin receptor expression in the endometrium. This results in the suppression of the pulsatile endometrial release of the luteolytic hormone prostaglandin F2-alpha, hindering the regression of the corpus luteum (luteolysis) and therefore a return to ovarian cyclicity. This, and a possible direct effect of IFN-tau on prostaglandin synthesis, leads in turn to continued ovarian progesterone secretion, which stimulates the secretion by the endometrium of the nutrients required for the growth of the conceptus. In summary, displays particularly high antiviral and antiproliferative potency concurrently with particular weak cytotoxicity, high antiluteolytic activity and immunomodulatory properties. In contrast with other IFNs, IFN-tau is not virally inducible.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedOvine interferon-tau (ovIFN-tau) is a pregnancy recognition hormone required for normal embryonic development in sheep. In addition to its novel role in reproductive physiology, ovIFN-tau displays antiviral and antiproliferative activities similar to the IFN-alpha subtypes. To probe the structural basis for its unique activity profile, the crystal structure of ovIFN-tau has been determined at 2.1 A resolution. The fold of ovIFN-tau is similar to the previously determined crystal structures of human IFN-alpha2b and human and murine IFN-beta, which each contain five alpha-helices. Comparison of ovIFN-tau with huIFN-alpha2b, huIFN-beta, and muIFN-beta reveals unexpected structural differences that occur in regions of considerable sequence identity. Specifically, main-chain differences up to 11 A occur for residues in helix A, the AB loop, helix B, and the BC loop. Furthermore, these regions are known to be important for receptor binding and biological activity. Of particular interest, a buried ion pair is observed in ovIFN-tau between Glu71 and Arg145 which displaces a conserved tryptophan residue (Trp77) from the helical bundle core. This ion pair represents a major change in the core of ovIFN-tau compared to huIFN-alpha2b. Based on amino acid sequence comparisons, these ovIFN-tau structural features may be conserved in several human IFN-alpha subtypes and IFN-omega. The structure identifies potential problems in interpreting site-directed mutagenesis data on the human IFN-alpha family that consists of 12 proteins. Crystal structure of ovine interferon-tau at 2.1 A resolution.,Radhakrishnan R, Walter LJ, Subramaniam PS, Johnson HM, Walter MR J Mol Biol. 1999 Feb 12;286(1):151-62. PMID:9931256[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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