Untitled Quiz

<p>They can alter the receptor's functional activity. (C)</p> Signup and view all the answers

<p>Phosphorylation (D)</p> Signup and view all the answers

<p>It has three extracellular and three intracellular loops. (A)</p> Signup and view all the answers

<p>GPCRs and G-proteins. (A)</p> Signup and view all the answers

<p>They have a conserved structure across different GPCRs. (C)</p> Signup and view all the answers

<p>It regulates the isomerization of receptors between inactive and active conformations. (B)</p> Signup and view all the answers

<p>They are the target of the majority of prescribed drugs. (A)</p> Signup and view all the answers

<p>A diverse array, including neurotransmitters and lipids. (D)</p> Signup and view all the answers

<p>According to their sequence homology. (B)</p> Signup and view all the answers

<p>They are constitutively active. (C)</p> Signup and view all the answers

<p>Within the hydrophobic core of the receptor. (B)</p> Signup and view all the answers

<p>Class A - Rhodopsin-like group. (D)</p> Signup and view all the answers

<p>They undergo separation and twisting during receptor activation. (D)</p> Signup and view all the answers

<p>PARs are auto-ligands that initiate receptor activation. (C)</p> Signup and view all the answers

<p>It maintains activation of β arrestin-dependent effects. (C)</p> Signup and view all the answers

<p>Specific LOF mutations. (A)</p> Signup and view all the answers

<p>Trapping the receptor in the RER. (A)</p> Signup and view all the answers

<p>They prevent the receptor from reaching the plasma membrane. (B)</p> Signup and view all the answers

<p>They interfere with agonist binding. (B)</p> Signup and view all the answers

<p>They require interaction with another protein to be routed to the plasma membrane. (D)</p> Signup and view all the answers

<p>G protein-dependent effects. (D)</p> Signup and view all the answers

<p>Phosphorylation (D)</p> Signup and view all the answers

<p>Alters protein targeting (C)</p> Signup and view all the answers

<p>Labels proteins for degradation (D)</p> Signup and view all the answers

<p>Regulation of protein interactions (B)</p> Signup and view all the answers

<p>Lipidation (D)</p> Signup and view all the answers

<p>They interfere with the ability to bind G proteins. (B)</p> Signup and view all the answers

<p>Both wild-type and mutated GPCRs (A)</p> Signup and view all the answers

<p>They make GPCRs sensitive to inert positive allosteric modulators. (B)</p> Signup and view all the answers

<p>Their structure changes based on the bound nucleotide. (D)</p> Signup and view all the answers

<p>Biased activation affecting specific protein interactions. (C)</p> Signup and view all the answers

<p>They may have altered responses to normal agonists. (B)</p> Signup and view all the answers

<p>They act as molecular switches that interact with downstream proteins. (D)</p> Signup and view all the answers

<p>It participates in reversible interactions with higher affinity. (D)</p> Signup and view all the answers

<p>They couple GPCRs to various effector proteins. (D)</p> Signup and view all the answers

<p>It causes ADP-ribosylation, leading to loss of GTPase activity. (A)</p> Signup and view all the answers

<p>Phospholipase C (PLC) (C)</p> Signup and view all the answers

<p>Inhibition of adenylyl cyclase (AC) activity. (C)</p> Signup and view all the answers

<p>Myristoylation and palmitoylation (A)</p> Signup and view all the answers

<p>They promote the dissociation of GTP from G-proteins. (A)</p> Signup and view all the answers

<p>They facilitate the dissociation of GDP and promote GTP binding. (B)</p> Signup and view all the answers

<p>Phosphorylation of various proteins affecting multiple cellular processes. (B)</p> Signup and view all the answers

G-protein coupled receptors are a large family of cell surface receptors that are involved in signal transduction pathways. They are characterized by their seven transmembrane domains, which form a serpentine structure.

Another name for GPCRs. Stands for 'seven transmembrane receptors.'

A descriptive term for GPCRs because of their snake-like, coiled structure within the cell membrane.

The parts of the GPCR that stick outside of the cell membrane. They are responsible for binding signaling molecules (like hormones, neurotransmitters, etc.).

The parts of the GPCR that are inside the cell membrane. They interact with G proteins, which relay the signal inside the cell.

A conserved amino acid sequence (Aspartate-Arginine-Tyrosine) found in the second intracellular loop (IL2) of GPCRs. Essential for GPCR function.

Specific amino acid residues on the GPCR that can be modified by the addition of a phosphate group. This modification can regulate the activity of the receptor.

A well-studied GPCR that binds to adrenaline (epinephrine). It is involved in various physiological processes, including heart rate regulation.

GPCRs undergo a conformational change upon ligand binding, transitioning from an inactive to an active state. This involves a separation of transmembrane domains (TM-III and TM-VI) and a twist in TM-VI, pulling the third cytoplasmic loop (IL3) into the cell.

The largest known receptor family, constituting over 1% of the human genome. It includes over 800-950 genes and comprises receptors for various molecules: neurotransmitters, odorants, lipids, neuropeptides, and large glycoprotein hormones.

GPCRs are grouped into six main subfamilies or classes based on sequence homology. Class A is the rhodopsin-like group, encompassing most GPCRs.

Low-molecular-mass ligands (amines, nucleotides, eicosanoids) bind to sites within the hydrophobic core of GPCRs. Peptide and glycoprotein hormones bind to sites on the exterior face of the receptor.

The process starts with a ligand binding to a GPCR, activating the receptor, which then interacts with a G protein. The activated G protein triggers the activation of downstream effectors, leading to a cellular response.

GPCRs are crucial for transmitting signals from various stimuli in the body. They are targeted by a significant proportion of approved drugs, playing a major role in drug development.

These GPCRs include receptors for calcium ions (Ca2+), glutamate, and GABAB. They have large N-terminal extensions where ligands bind.

Some GPCRs exhibit a low level of activity even in the absence of an agonist. This is called basal activity.

The process by which GPCRs become less responsive to stimulation after prolonged exposure to an agonist. This can occur through internalization of the receptor or by phosphorylation of the receptor.

Loss-of-function mutations are genetic changes that impair the normal function of a protein, including GPCRs.

Some LOF mutations specifically affect the basal activity of GPCRs, either reducing or eliminating it.

Some LOF mutations affect the overall structure of the GPCR, preventing it from reaching the cell membrane.

Some LOF mutations disrupt the function of interacting proteins that are necessary for GPCR trafficking to the cell membrane.

Adding a phosphate group to a protein. This happens primarily on serine, threonine, or tyrosine residues. It's crucial for various cellular processes like cell growth and signal transduction.

Adding a sugar molecule (carbohydrate) to a protein. This occurs mainly on asparagine, hydroxylysine, serine, or threonine residues. It influences protein folding, stability, and activity.

Adding a lipid molecule to a protein. This process helps anchor proteins to membranes, allowing them to be localized to specific cellular compartments.

Adding a small protein called ubiquitin to a protein. This acts like a 'death tag' for the protein, marking it for destruction.

The level of signaling activity a GPCR exhibits even when its ligand (the signal molecule) isn't bound. It's like the receptor's internal 'chatter'.

Mutations in GPCRs that prevent them from functioning properly. They may interfere with G-protein binding or signaling.

Mutations that enhance GPCR activity, making them either more sensitive to their natural ligand or activated by other molecules.

When a ligand (signaling molecule) activates one pathway but not another within GPCRs. It's like a 'selective' signal, affecting specific parts.

Proteins that act as molecular switches, turning on or off signaling pathways within the cell. They bind to GTP or GDP, changing their shape and activity.

G-proteins bind to either GTP (active form) or GDP (inactive form). This binding cycle regulates their activity.

G-proteins are composed of three subunits (alpha, beta, and gamma) that work together.

A specific combination of a G-protein-coupled receptor (GPCR) and the stimulatory alpha subunit (Gαs). This complex activates adenylyl cyclase, leading to the production of cAMP.

A specific combination of a GPCR and the alpha subunit (Gαq). This complex activates phospholipase C (PLC), leading to the production of IP3 and DAG.

Regulators of G-protein Signaling. These proteins promote the hydrolysis of GTP into GDP, turning off the activity of the G-protein.

A bacterial toxin that modifies the alpha subunit (Gαs) of the G-protein, leading to its permanent activation, resulting in high levels of cAMP.