5 Questions
Explain the process of how G protein-coupled receptors (GPCRs) become activated and signal inside the cell.
When a GPCR encounters an activated receptor, the α subunit exchanges GDP for GTP, dissociates from the β and γ subunits, and becomes active. This activation triggers intracellular signaling.
Where are the receptors for polar signaling molecules such as neurotransmitters and growth factors located? And where are the receptors for nonpolar signaling molecules such as steroid hormones located?
Receptors for polar signaling molecules are located on the plasma membrane, while receptors for nonpolar signaling molecules, such as steroid hormones, are located in the cytosol or in the nucleus.
What are G proteins composed of and how do they become active?
Heterotrimeric G proteins are composed of three subunits, denoted α, β, and γ. G proteins become active when the α subunit exchanges GDP for GTP.
How are G protein signals amplified in the cytosol?
G protein signals are amplified in the cytosol by cAMP synthesis and Protein kinase A activation.
What does the cellular response depend on in terms of signaling pathways?
The cellular response depends on the integration of multiple signaling pathways in a single cell.
Test your knowledge of GPCR/G-protein signaling, adrenalin signaling, smell, and opioid receptor signaling with this quiz. Explore how signaling molecules bind to and activate cell-surface and intracellular receptors, causing conformational changes and signaling inside the cell.
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