Steroid Hormone Receptors Features Quiz

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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)?

As homo- or heterodimers to HREs composed typically of two core hexameric motifs (A) Signup and view all the answers

What is the characteristic feature of ER binding?

Binds palindromic HSE (C) Signup and view all the answers

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

Specific base sequences interaction (B) Signup and view all the answers

What happens to the receptor after it binds the hormone?

Changes shape, sheds HSP and migrates into nucleus (A) Signup and view all the answers

Where are heterodimeric RXR NRs located under basal state?

Nucleus (A) Signup and view all the answers

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

Promote coactivator binding (D) 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?

LXXX(I/L)XXX(I/L) (B) Signup and view all the answers

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

Shift in H12 that promotes coactivator binding (C) Signup and view all the answers

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

Acetylate histones (D) Signup and view all the answers

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

Binds 2x AGAACA (A) Signup and view all the answers

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

Subdomain 1 (D) Signup and view all the answers

What leads to the induction of nuclear transport for GR?

Time-dependent nuclear translocation of GFP-GR (C) Signup and view all the answers

Where are homodimeric NRs located under basal state?

Cytoplasm (D) Signup and view all the answers

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

Inhibit transcription (A) Signup and view all the answers

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

Corepressor inhibition (A) Signup and view all the answers

What is the common basic structure shared by steroid hormones?

Cholesterol (C) Signup and view all the answers

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

It participates in DBD dimerization and makes non-specific contacts with the DNA backbone (A) Signup and view all the answers

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

They make contacts with the minor groove of the DNA (A) Signup and view all the answers

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

Near the middle (C) Signup and view all the answers

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

It makes non-specific contacts with the DNA backbone (C) 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?

Base-specific contacts (C) Signup and view all the answers

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

Interact with the major elements of genomic response elements (C) Signup and view all the answers

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

Zinc atoms (A) Signup and view all the answers

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

A three-layered, antiparallel helical sandwich (B) Signup and view all the answers

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

PPARg (D) Signup and view all the answers

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

Conserved b-turn (A) Signup and view all the answers

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

Buried within the bottom half of the LBD (C) Signup and view all the answers

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

Extensive and include different structural elements through the LBD (D) Signup and view all the answers

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

PPARg (A) Signup and view all the answers

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

Unliganded structures are more compact (D) Signup and view all the answers

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

Ligand-binding pocket (A) Signup and view all the answers

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

Central core layer of three helices (B) Signup and view all the answers