Which of the following is the best description of how a G protein coupled receptor responds to a ligand binding? Binding of ligand to the receptor causes the G protein to swap out GTP for GDP Binding of ligand to the receptor causes the G proteins to dimerize and trigger cross-phosphorylation Binding of ligand to the receptor causes the G protein to become activated, then the G protein travels through the plasma membrane to activate an enzyme Binding of ligand to the G protein triggers it to swap out GDP for GTP, causing it to become activated

Which of the following is the best description of how a G protein coupled receptor responds to a ligand binding? Binding of ligand to the receptor causes the G protein to swap out GTP for GDP Binding of ligand to the receptor causes the G proteins to dimerize and trigger cross-phosphorylation Binding of ligand to the receptor causes the G protein to become activated, then the G protein travels through the plasma membrane to activate an enzyme Binding of ligand to the G protein triggers it to swap out GDP for GTP, causing it to become activated

Human Physiology: From Cells to Systems (MindTap Course List)

9th Edition

ISBN:9781285866932

Author:Lauralee Sherwood

Publisher:Lauralee Sherwood

Chapter4: Principles Of Neural And Hormonal Communication

Section4.5: Intercellular Communication And Signal Transduction

Problem 3CYU: Outline the three general means by which binding of a water soluble extracellular chemical messenger...

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Put the following steps for the outline of the growth factor signaling pathway in order: Map Kinase Kinase is Phosphorylated Proteins involved in gene transcription are activated Growth factor binds to its receptor in the cytoplasmic membrane Receptor recruits adaptor protein and GEF Autophosphorylation of tyrosine residues on the receptor Structural change of the receptor activates Tyrosine Kinase Map Kinase Kinase Kinase is phosphorylated Ras, a small GTPase, is activated by the exchange of GTP for GDP Map Kinase is Phosphorylated Map Kinase enters the nucleus
Which of the following is true of signal transduction mediated by protein tyrosine kinases production of cAMP phosphoinositides are activated arrestins compete with G-proteins phosphorylation of tyrosine residues
You perform a competition study on a GPCR. You have isolated the plasma membrane from cells which contains the GPCR of interest. If an agonist and an inverse agonist are at equal concentrations in your study but the inverse agonist has a 10 x higher affinity for the receptor than the agonist, what would you expect to be the overall outcome to be? More of the agonist is bound and so most of the receptor is in its active conformation and is stimulated More of the inverse agonist is bound and so most of the receptor is in its inactive conformation and is unstimulated.
Cytokine receptors and tyrosine kinase receptors are similar in all of the following ways EXCEPT one. Which one is the exception? O They are both down-regulated by lysosomal degradation They both involve receptor exoplasmic domain dimerization They both result in an effector protein entering the nucleus O They both involve cytosolic domain phosphorylation
The G protein coupled receptor (GPCR) pathway elicits diverse intracellular responses in different cells. The basic steps of GPCR signaling are outlined in this diagram. Which of the following statements correctly describes the process of GPCR signaling? The GPCR activation is reversible after the signal of the ligand diminishes. The membrane-embedded enzyme uses GTP as a secondary messenger to initiate gene expression. The ligand attaches to both the GPCR and the membrane-embedded enzyme to activate the GPCR pathway. The ligand-bound GPCR sends a GTP molecule to an enzyme in the membrane and switches it into an active state.
Which of the following is most likely an example of signaling through a transmembrane receptor? The influenza virus recognizes specific proteins on the surface of host cells, causing the entrance of genetic materials into the cytoplasm of the host cells. Low-density lipoproteins (LDL) bind to receptor proteins found on the membrane of receiving cells, triggering its internalization into the receiving cells. The binding of interleukin-6 (IL-6) to the interleukin-6 receptor causes the activation of protein kinases in the cytoplasm, activating the transcription factor NF-κB. The binding of aldosterone to the aldosterone receptor activates its transcription activity, leading to the transcription of genes that promote the uptake of ions and water.
The figure below illustrates a model of a signal transduction cascade, initiated by the bind- ing of a ligand to a membrane-bound receptor. ligand A partial model of a signal transduction pathway A inactivated molecules B -receptor protein A D activated molecule 1 Based on the figure, which of the following describes the most likely outcome of a mutation that changes the intracellular region of receptor protein A? activated molecule 2 activated molecule 3 The receptor will not activate molecule 1, but the activation of molecules 2 and 3 will continue at lower rates. Molecule 1 will not become activated, preventing the activation of molecules 2 and 3 and the subsequent cellular response. с The ligand will not be able to bind the membrane-bound receptor, preventing the signal transduction pathway from initiating. The ligand that binds to protein A will not enter the cell, preventing the cellular response from occurring.
In this mechanim of receptor regulation, there is uncoupling of the signaling pathway. Even though the ligand is bound to the receptor located in the plasma membrane, downstream signaling is not occuring. This is best described as: Answers A-D A receptor internalization B receptor desensitization C receptor sensitization 5 D receptor downregulation
Histamine is a chemical substance released in inflammatory and allergic response. The histamine H1 receptor is a G protein-coupled receptor that activates phospholipase C in response to the binding of histamine. Arrange the data below showing the process of histamine signal transduction from the H1 receptor. Calcium ions flow through ligand-gated ion channel. Phosphorylation cascade leads to the activation of a cellular response. Calcioum ions activate a protein, leading to a cellular response. Enzyme cleaves PIP2, forming DAG and IP3. Calcium iom concentration increases in the cytosol. IP3 binds to a ligand-gated ion channel in thw ER membrane.
An SH2-containing protein contains a mutation that changes its binding pocket such that tyrosine and phosphotyrosine bind with equal afﬁnity. As a result, MEK activity: does not change with receptor dimerization and transautophosphorylation decreases due to changes in Raf activation increases with ligand binding-induced dimerization decreases due to allosteric inhibition of SH2-domain binding
TGF-B Receptor I (RI) phosphorylation of Smad2/3 does all of the following EXCEPT: activate Smad2/3 binding to the Co-Smad Smad4 dissociate intramolecular binding of Smad2/3 MH1 and MH2 domains. RI phosphorylation of Smad2/3 does all of these things. release Smad2/3 from the nucleus into the cytoplasm unmask the Smad2/3 nuclear localization signal (NLS).
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