G proteins are called so because they bind guanine nucleotides, specifically GDP and GTP.
Here's a breakdown:
- G proteins are heterotrimers, meaning they consist of three different subunits.
- These proteins reside on the inner surface of the plasma membrane.
- They interact with transmembrane receptors called G protein-coupled receptors (GPCRs), which are activated by hormones and other signals.
- According to the provided reference, a crucial feature of G proteins is their ability to bind the guanine nucleotides GDP (guanosine diphosphate) and GTP (guanosine triphosphate).
In summary, the "G" in G protein stands for guanine nucleotide-binding protein, reflecting their essential function of interacting with GDP and GTP.
