Signaling activity of G proteins is controlled by GTPase activating proteins (GAPs) and Guanine exchange factors (GEFs). What are the mechanisms by which GAPS and GEFs control G protein functions? GEFS inhibit G protein functions by stimulating GTP hydrolysis; GAPs activate G protein functions by stimulating GDP-GTP exchange. GAPS inhibit G protein functions by stimulating GTP hydrolysis; GEFs activate G protein functions by stimulating GDP-GTP exchange. GEFS inhibit G protein functions by stimulating GTP hydrolysis; GAPS activate G protein functions by inhibiting GDP-GTP exchange. GAPs stimulate G protein functions by blocking GTP hydrolysis; GEFs inhibit G protein functions by stimulating GTP-GDP exchange. GAPS inhibit G protein functions by stimulating GDP-GTP exchange; GEFS activate G protein functions by stimulating GTR budu

You are studying a drug that affects a cAMP signalling pathway that is normally initiated when a signalling molecule binds to a G-protein coupled receptor. You determine that the drug prevents the hydrolysis of GTP bound to G-proteins in this pathway.  Describe the impact, if any, that this drug would have on the G-protein coupled receptor (GPCR), assuming that the pathway has been activated by the presence of the signalling molecule (first messenger).  Include an explanation for your response.

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.…

GTP is an important high-energy molecule that facilitates the activation of many cellular sig- nal transduction pathways. Certain genetic dysfunctions can inhibit the ability of a cell to synthesize GTP. Which of the following describes the most direct result of GTP synthesis inhibition? A B с D The cell would be able to carry out reception and transduction but would not be able to produce the cellular response in the relevant signal transduction pathway. The G protein-coupled receptor will not be able to bind corresponding ligands, inhibiting the reception components of the relevant signal transduction pathway. The cell will use ATP instead of GTP to activate the G protein on the intracellular region of the G protein-coupled receptor. The cell would not be able to activate G proteins on the intracellular regions of G pro- tein-coupled receptors.