Steroid Hormone Receptors Features Quiz
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Questions and Answers

What is the function of the Activation Function 1 (AF-1) surface?

  • Contains the core AF-2 domain
  • Binds to a specific ligand
  • Interacts with co-regulator proteins (correct)
  • Forms a zinc finger DBD

    • Which type of receptors have a very large ligand binding pocket, allowing binding of differently sized ligands?

  • Unspecified monomeric receptors
  • Unliganded receptors
  • Homo- or heterodimers
  • PPARg receptors (correct)

    • What is the difference in structure between liganded and unliganded receptors?

  • Liganded structures are more compact than the unliganded ones (correct)
  • Both have different levels of flexibility
  • Both have similar compactness
  • Unliganded structures are more compact than the liganded ones

    • How do most receptors bind to hormone response elements (HREs)?

    <p>As homo- or heterodimers to HREs composed typically of two core hexameric motifs</p> Signup and view all the answers

    What is the characteristic feature of ER binding?

    <p>Binds palindromic HSE</p> Signup and view all the answers

    What contributes to the specificity of binding of different steroid hormone nuclear receptors?

    <p>Specific base sequences interaction</p> Signup and view all the answers

    What happens to the receptor after it binds the hormone?

    <p>Changes shape, sheds HSP and migrates into nucleus</p> Signup and view all the answers

    Where are heterodimeric RXR NRs located under basal state?

    <p>Nucleus</p> Signup and view all the answers

    What is the function of the leucine residues within the hydrophobic groove of the AF-2 surface?

    <p>Promote coactivator binding</p> Signup and view all the answers

    Which motif is contained in the corepressors such as NCoR and interacts at the same hydrophobic AF2 surface with H12 in a different position?

    <p>LXXX(I/L)XXX(I/L)</p> Signup and view all the answers

    What is the result of ligand (agonist) binding to RXR heterodimers?

    <p>Shift in H12 that promotes coactivator binding</p> Signup and view all the answers

    What is the function of CBP/p300 in the context of histone modification?

    <p>Acetylate histones</p> Signup and view all the answers

    What is the characteristic feature of steroid receptors when binding palindromic HSE?

    <p>Binds 2x AGAACA</p> Signup and view all the answers

    What contributes to the specificity of binding of different Steroid hormone NRs?

    <p>Subdomain 1</p> Signup and view all the answers

    What leads to the induction of nuclear transport for GR?

    <p>Time-dependent nuclear translocation of GFP-GR</p> Signup and view all the answers

    Where are homodimeric NRs located under basal state?

    <p>Cytoplasm</p> Signup and view all the answers

    What is the role of heat shock proteins (HSP) in regulating steroid receptors?

    <p>Inhibit transcription</p> Signup and view all the answers

    What prevents heterodimeric RXR NRs from being active in the basal state?

    <p>Corepressor inhibition</p> Signup and view all the answers

    What is the common basic structure shared by steroid hormones?

    <p>Cholesterol</p> Signup and view all the answers

    What is the function of the peptide loop in the DNA binding Dimer formation region?

    <p>It participates in DBD dimerization and makes non-specific contacts with the DNA backbone</p> Signup and view all the answers

    Where are C-terminal extensions (CTEs) found in some nuclear receptors like LRH-1 and GCNF located?

    <p>They make contacts with the minor groove of the DNA</p> Signup and view all the answers

    In which part of the polypeptide chain are the highly conserved DNA-binding domains located?

    <p>Near the middle</p> Signup and view all the answers

    What is the role of the second subdomain helix in the DNA binding process?

    <p>It makes non-specific contacts with the DNA backbone</p> Signup and view all the answers

    What type of contacts do some nuclear receptors, like LRH-1 and GCNF, make with the minor groove of the DNA?

    <p>Base-specific contacts</p> Signup and view all the answers

    Which residues on genomic response elements do the first subdomain residues of NR DBDs interact with?

    <p>Interact with the major elements of genomic response elements</p> Signup and view all the answers

    What is represented as spheres in the Cartoon representation of folded GR DBD highlighting NR?

    <p>Zinc atoms</p> Signup and view all the answers

    What is the structure of the ligand-binding domain (LBD) mainly composed of?

    <p>A three-layered, antiparallel helical sandwich</p> Signup and view all the answers

    Which nuclear receptor contains an extra helix designed H29 in its overall structure?

    <p>PPARg</p> Signup and view all the answers

    What is the poorly structured insertion between helices H1 and H3 found in the VDR?

    <p>Conserved b-turn</p> Signup and view all the answers

    In which region of the LBD are the ligand-binding pockets located?

    <p>Buried within the bottom half of the LBD</p> Signup and view all the answers

    What are the contacts with the ligand within the LBD described as?

    <p>Extensive and include different structural elements through the LBD</p> Signup and view all the answers

    Which receptor has a very large ligand binding pocket, allowing binding of differently sized ligands?

    <p>PPARg</p> Signup and view all the answers

    What is a characteristic difference between liganded and unliganded structures of receptors?

    <p>Unliganded structures are more compact</p> Signup and view all the answers

    What is mainly hydrophobic and buried within the bottom half of the LBD?

    <p>Ligand-binding pocket</p> Signup and view all the answers

    Which element creates a cavity, the ligand-binding pocket, within the LBD?

    <p>Central core layer of three helices</p> Signup and view all the answers

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