What is the Difference Between G Protein Coupled Receptors and Receptor Tyrosine Kinases?

G Protein Coupled Receptors (GPCRs) and Receptor Tyrosine Kinases (RTKs) are two types of cell surface receptors involved in cell signaling. They have distinct structures and mechanisms of action:

• GPCRs:
• Contain seven transmembrane domains.
• Use GTP as their energy source.
• Typically activate intracellular signaling pathways via G proteins and second messengers.
• Single ligand binding induces only one cell response.
• RTKs:
• Have two similar monomers, consisting of a single peptide chain.
• Use ATP as their energy source.
• Normally activate intracellular signaling pathways via phosphorylation (when adaptor proteins bind).
• Ligand binding induces multiple cell responses.

Cross-talk between GPCRs and RTKs can occur at several levels, including the receptor-to-receptor level and at crucial downstream points, such as phosphatidylinositol-3-kinase, Akt/protein kinase B, and the mitogen-activated protein kinase cascade. Regulation of GPCRs by non-receptor tyrosine kinases, such as Src family members, also operates in signaling.

Comparative Table: G Protein Coupled Receptors vs Receptor Tyrosine Kinases

G protein-coupled receptors (GPCRs) and receptor tyrosine kinases (RTKs) are both cell surface receptors involved in cell signaling processes. Here is a table highlighting the key differences between them:

GPCRs are characterized by their seven transmembrane domains and activate a G protein when a ligand binds to them. They associate with G proteins and GTP in the cell signaling process. On the other hand, RTKs have a single transmembrane domain and form and phosphorylate a tyrosine dimer when a ligand binds to them. They are enzyme-linked receptors associated with tyrosine and ATP. Single ligand binding triggers multiple cell responses in RTKs, while only one cell response is triggered in GPCRs.