Arrange following the boxed information in sequence regarding the dissociation and reassociation of G proteins following the activation of a G protein coupled receptor. GTP-bound Ga, dissociates from B and y cıhunits Ga, exchanges GTP for GDP Gas reassociates with By subunits and the rorentor reforms Binding of the ligand to a G-protein counled rerentor GTP-bound Ga, binds and activates ardenvlul rurlace GTP is hydrolyzed and GDP bound Gs suhınit diccoriates Conformational change Increased synthesis of CAMP from ATP

Item21       Item 21   Neurons have a _______ membrane potential of –70mV. In other words, this is their stable membrane potential under normal conditions.   Fill in the blank Fill in the blank Item22       Item 22 When a skin wound is healing, cell contact on all sides is a strong stimulus for cell division. Group startsTrue or False   Item23       Item 23 Which choice describes the activation steps of a G protein-coupled receptor properly (and in correct order)? Multiple Choice   Ligand binds to receptor, G protein activated, effector protein activated, second messenger made available   Ligand binds to receptor, second messenger activated, G protein turned on, protein kinase activated   Protein kinase activated, ion channel opened, ions enter and activate second messenger, G protein turned on   Ion channel opened, G protein activated, second messenger synthesized, phosphatase ends signal

Hormone H regulates these effects via its receptors which are found at both the cell surface (csRH) and within the cell (içRH). The signalling pathways that become activated in the presence of hormone H are depicted and described below. hormone H. H H extracellular fluid inactive GTP inactive RAS Lyn cell-surface receptor for H (csR») icR GDP RAS-GTP hexose metabolism cell survival H icR G, phase (resting) Raf HK GSK-3P MEK M G2 icR - hexose kinase ERK promoter HRE CDK1 Cyclin A nucleus cyclin A Fos A promoter Created in BioRender.com bio Signalling via the cell surface receptor Hormone H mediates its cell cycle stimulatory and pro-survival effects by binding to and activating the cell surface hormone H receptor (csRH). The activated CSRH activates Lyn, which activates RAS and ultimately the Raf/MEK/ERK kinase cascade. Active ERK: o phosphorylates and inactivates GSK-3B. Inhibition of GSK-3ß promotes cell survival. inhibits p27, preventing it from inhibiting cell cycle progression.…

Continuous exposure of a G protein-coupled receptor to its ligand leads to a phenomenon known as desensitization. Describe several molecule mechanisms for receptor desensitization

What is meant by intrinsic GTPase activity? Exchange of GDP for GTP on the a-subunit of the G protein Inhibition of GBCR receptor activity Activation of Adenylyl Cyclades Breakdown of cAMP by phosphodiesterase Spontaneous hydrolysis of GTP on the a-subunit of the G-protein

RGS proteins accelerate the GAP activity of Gα subunits.  What is the direct result of this GAP activity?  - hydrolysis of GTP, resulting in a GDP-bound Gα - phosphorylation of GDP to GTP, resulting in a GTP-bound Gα - an exchange of GTP for GDP bound to Gα - an exchange of GDP for GTP bound to Gα

You decide to investigate cell signaling of a pair of newly identified GPCRs, GPCR-W and GPCR-Z. Each binds the same ligand, but activates different downstream heterotrimeric G-proteins that act on adenylyl cyclase. You discover that ligand binding has opposite effects on adenylyl cyclase activity for each receptor. GPCR-W causes an increase in adenylyl cyclase activity, while GPCR-Z causes a decrease in adenylyl cyclase activity. You obtain a cell line expressing GPCR-W, GPCR-Z, the relevant G-proteins, and adenylyl cyclase. There is baseline adenylyl cyclase activity producing a baseline amount of cAMP. You embark on a research project to characterize the following mutations in the components of the signaling pathway. 2. Will each of the following mutations increase or decrease the levels of cAMP inside the cell upon adding the ligand to the cell culture? A mutation in Gi that prevents release of bound GDP. A mutation in Gs that prevents GTP hydrolysis. A mutation in Gi that…

From the Hill Plot below, the of the first binding event for the receptor-ligand system under study is: Q1 4nM Ο 10 μΜ -2 nM 2 nM Calculate the Hill Coefficient from the receptor-ligand binding data below: Q2 4 100 2 3 (0-1) 60 log 10 8 6 4 2 0 -2 -4 -6 -6 -4 -2 0 2 4 log [L] (nM) 6 8 10

Which of the following will bind (directly or indirectly) to the phosphate groups on a tyrosine kinase receptor? Ras-GEF Ran-GEF Rab-GEF Sar-GEF O Raf-GEF

2+ Activation of 5-HT2A Increases cytosolic free Ca²+ Concentration ([Ca²+]) Via a Signaling cascade. At rest, neurons have a cytosolic Ca Concentration of 100nM. The ex- Tra cellular free calcium concentration is typically 1.2m M. Calculate the resting potential (at equilibrium) produced by the neuron as a result of the calcium ion concentration gradient. (Report your answer in mV ).