What is the Difference Between Heteromeric G Protein and Monomeric G Protein?

The main difference between heteromeric G proteins and monomeric G proteins lies in their structure and composition.

Heteromeric G proteins, also known as heterotrimeric G proteins, are large membrane-associated proteins composed of three subunits: alpha (α), beta (β), and gamma (γ). These proteins are activated by G protein-coupled receptors (GPCRs) and play a crucial role in transmitting signals from various stimuli outside a cell to the interior. When a ligand binds to a GPCR, the GPCR acquires GEF (guanine nucleotide exchange factor) ability, which activates the G protein by exchanging the GDP on the alpha subunit to GTP.

On the other hand, monomeric G proteins are small membrane-associated proteins made up of only an alpha subunit. They function as monomeric small GTPases and belong to the Ras superfamily of small GTPases. Like heterotrimeric G proteins, monomeric G proteins also bind GTP and GDP and are involved in signal transduction.

In summary, the key differences between heteromeric G proteins and monomeric G proteins are:

• Heteromeric G proteins are large, membrane-associated proteins composed of three subunits (α, β, and γ), while monomeric G proteins are small, membrane-associated proteins composed of only an alpha subunit.
• Heteromeric G proteins are activated by G protein-coupled receptors, whereas monomeric G proteins function as monomeric small GTPases.

Comparative Table: Heteromeric G Protein vs Monomeric G Protein

Heteromeric G proteins and monomeric G proteins differ in size, structure, and composition. Here is a table summarizing their differences:

Both heteromeric and monomeric G proteins are involved in signal transduction and play crucial roles in various cellular pathways. Heteromeric G proteins are large proteins made up of alpha (α), beta (β), and gamma (γ) subunits, while monomeric G proteins are small proteins made up of only an alpha subunit.