Cell Communication 2

<p>Beta-adrenergic receptor (B)</p> Signup and view all the answers

<p>Role of G proteins in cell signaling (A)</p> Signup and view all the answers

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

<p>Allosterically activates PKA (D)</p> Signup and view all the answers

<p>Epinephrine (B)</p> Signup and view all the answers

<p>Phosphorylates cellular proteins (A)</p> Signup and view all the answers

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

<p>Gs is activated (B)</p> Signup and view all the answers

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

<p>Generating an intracellular second messenger (D)</p> Signup and view all the answers

<p>Exchanges bound GDP for GTP (B)</p> Signup and view all the answers

<p>Activation by the ligand/GPCR complex (B)</p> Signup and view all the answers

<p>GTPase Activator Proteins (GAPs) (A)</p> Signup and view all the answers

<p>Phosphodiesterase (PDE) (B)</p> Signup and view all the answers

<p>G protein α-subunit (D)</p> Signup and view all the answers

<p>Speed up the intrinsic GTPase activity of G protein (C)</p> Signup and view all the answers

<p>Draws to the receptor and phosphorylates it (C)</p> Signup and view all the answers

<p>Removal of receptors from the membrane through endocytosis (C)</p> Signup and view all the answers

<p>Dissociates from receptors in endocytic vesicles (B)</p> Signup and view all the answers

<p>Dissociation of epinephrine from its receptor (D)</p> Signup and view all the answers

<p>β-adrenergic receptor kinase (βARK) (C)</p> Signup and view all the answers

<p>Mediate responses to signals from other cells (A)</p> Signup and view all the answers

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

<p>350 (A)</p> Signup and view all the answers

<p>Act as molecular binary switches with built-in timers (A)</p> Signup and view all the answers

<p>β-adrenergic receptor (D)</p> Signup and view all the answers

<p>Role of G proteins in signal transduction in cells (C)</p> Signup and view all the answers

<p>It has GDP bound and is inactive (C)</p> Signup and view all the answers

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

<p>GTPase Activator Proteins (GAPs) (B)</p> Signup and view all the answers

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

<p>Activates Protein Kinase A (C)</p> Signup and view all the answers

<p>Stimulates effector enzymes/enzymes (B)</p> Signup and view all the answers

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

<p>Phosphorylates cellular proteins resulting in a cellular response (D)</p> Signup and view all the answers

<p>Epinephrine (B)</p> Signup and view all the answers

<p>Amplification of the hormone signal (D)</p> Signup and view all the answers

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

<p>Inhibition (B)</p> Signup and view all the answers

<p>Speed up signal termination by increasing G protein's GTP hydrolysis rate (B)</p> Signup and view all the answers

<p>β-adrenergic receptor kinase (βARK) (D)</p> Signup and view all the answers

<p>Promote re-sensitization by stopping the interaction between receptor and G protein (C)</p> Signup and view all the answers

<p>They dephosphorylate, allowing them to return to the membrane (C)</p> Signup and view all the answers

<p>Desensitization (B)</p> Signup and view all the answers

<p>Hydrolyze bound GTP to GDP, leading to pathway inactivation (D)</p> Signup and view all the answers

<p>Mediate most responses to signals from the external world and other cells (C)</p> Signup and view all the answers

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

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

<p>Discovery of G-proteins and their role in signal transduction in cells (D)</p> Signup and view all the answers

<p>Adenylate Cyclase (B)</p> Signup and view all the answers

<p>It activates adenylyl cyclase (D)</p> Signup and view all the answers

<p>Catalyze the hydrolysis of GTP to GDP (D)</p> Signup and view all the answers

<p>Beta-adrenergic receptor kinase (βARK) (D)</p> Signup and view all the answers

<p>Reduced cellular response (D)</p> Signup and view all the answers

<p>Dissociates from receptors in endocytic vesicles (D)</p> Signup and view all the answers

<p>Beta-adrenergic receptor kinase (βARK) (C)</p> Signup and view all the answers

<p>Deactivation of the pathway (A)</p> Signup and view all the answers

<p>It exchanges GDP for GTP (B)</p> Signup and view all the answers

<p>GTPase Activator Protein (GAP) (D)</p> Signup and view all the answers

<p>Generating cAMP from ATP (C)</p> Signup and view all the answers

<p>They activate effector proteins/enzymes (B)</p> Signup and view all the answers

<p>[cAMP] phosphodiesterase (PDE) (D)</p> Signup and view all the answers

<p>Activation by ligand/GPCR complex (D)</p> Signup and view all the answers

<p>Activation of Adenylyl Cyclase (AC) (B)</p> Signup and view all the answers

<p>Activating Adenylate Cyclase (D)</p> Signup and view all the answers

<p>Insulin (B)</p> Signup and view all the answers

<p>Inhibition of Adenylyl Cyclase (D)</p> Signup and view all the answers

<p>Amplification of the hormone signal (C)</p> Signup and view all the answers

<p>By becoming less sensitive through desensitization (C)</p> Signup and view all the answers

G proteins can self-inactivate which means they can turn themselves off after they have been activated.

Gs is a type of G protein that stimulates the production of cAMP in the cell.

There are approximately 900 different G protein-coupled receptors (GPCRs) found in humans.

The beta-adrenergic receptor is a well-studied GPCR that binds to adrenaline (epinephrine) and is a model for understanding GPCRs.

The scientists who discovered the role of G proteins in cell signaling were awarded the Nobel Prize in Physiology and Medicine in 1994.

G protein-coupled receptors (GPCRs) are a large family of receptors that include metabotropic receptors which bind to G proteins, triggering intracellular signaling cascades.

cAMP acts as a second messenger in the signal transduction pathway, binding to and activating Protein Kinase A (PKA).

Epinephrine is a hormone that boosts glycogenolysis, breaking down glycogen into glucose, while suppressing glycogenesis, the production of glycogen.

Protein Kinase A (PKA) is a key enzyme in the signal cascade. It phosphorylates (adds a phosphate group) to cellular proteins, triggering a specific cellular response.

Desensitization is a process that gradually decreases the sensitivity of a receptor to its ligand, effectively shutting down the signal pathway.

When Gs exchanges GDP for GTP, it becomes activated and can stimulate Adenylyl Cyclase to produce cAMP.

Somatostatin is a hormone that inhibits Adenylyl Cyclase activity, lowering the levels of cAMP.

GPCRs are like antennae on the cell surface, detecting signals from the outside world and converting them into intracellular signals.

The G protein alpha subunit (Gα) becomes activated when it exchanges bound GDP for GTP.

The β/γ complex dissociates from the G protein α-subunit when the G protein is activated by the ligand/GPCR complex.

GTPase Activator Proteins (GAPs) increase the intrinsic GTPase activity of G proteins, promoting the hydrolysis of GTP back to GDP, which inactivates the protein.

Phosphodiesterase (PDE) is responsible for breaking down cAMP, reducing the levels of cAMP, and ultimately ending the signal.

The G protein α-subunit hydrolyzes GTP to GDP and becomes inactive after a certain time, ensuring the signal is not perpetuated.

GAPs speed up the intrinsic GTPase activity of G protein, which in turn hydrolyzes GTP to GDP, causing the signal to be terminated.

β-adrenergic receptor kinase (βARK) phosphorylates the receptor, adding phosphate groups, which creates a binding site for β-arrestin and initiates desensitization.

Receptor sequestration is the process of removing receptors from the membrane into the cytoplasm through endocytosis. This reduces the number of receptors available for binding ligands, further contributing to desensitization.

β-arrestin dissociates from receptors in endocytic vesicles, allowing the receptors to re-sensitize and return to the cell membrane.

When the concentration of epinephrine falls, it dissociates from its receptor, leading to the deactivation of the pathway.

β-adrenergic receptor kinase (βARK) initiates receptor sequestration by phosphorylating the receptor, making it a target for β-arrestin, which triggers endocytosis and removes the receptor from the cell surface.

GPCRs act as mediators for responses to signals from other cells, allowing communication between cells and enabling complex cellular responses.

Gi is a type of G protein that inhibits the production of cAMP in the cell.

There are around 350 types of GPCRs in humans that are involved in detecting hormones and other endogenous ligands. These receptors are critical for a wide range of physiological processes.

G proteins act like molecular switches, cycling between an active state (GTP bound) and an inactive state (GDP bound), allowing for controlled and timed responses to signals.

The β-adrenergic receptor is a prototype for all GPCRs, known for its involvement in the 'fight or flight' response and commonly targeted by beta blockers to manage heart health.

The scientists who discovered the role of G proteins in signal transduction within cells were awarded the Nobel Prize in Physiology and Medicine in 1994.

Prior to activation, the G protein α subunit (Gα) has GDP bound and is in its inactive state, unable to trigger the signaling cascade.

Phosphodiesterase, an enzyme, is responsible for breaking down cAMP, reducing its levels and effectively reducing the signal.

The GTPase Activator Proteins (GAPs) determine how long the G protein remains 'on,' by accelerating the hydrolysis of GTP to GDP, leading to inactivation.

Upon activation by the GPCR, GTP replaces GDP on the G protein α subunit (Gα), switching it to an active state and initiating the signaling cascade.

Adenylyl Cyclase is an enzyme activated by the activated G protein (Gs) to convert ATP into cAMP, acting as a crucial link in the signal transduction pathway that ultimately leads to the downstream processes.