enzyme coupled receptors

What are enzyme-coupled receptors (ECRs)?

Cell surface receptors with an extracellular ligand-binding domain, a single transmembrane domain, and an intracellular domain that has intrinsic enzymatic activity or associates with intracellular enzymes

What are the key steps in ECR signal transduction?

1. Ligand binding triggering confirmational changes and oligomerisation.

2. Activation of enzymatic activity (intrinsic or associated enzymes)

3. Autophosphorylation or cross-phosphorylation.

4. Recruitment of signalling proteins.

5. Activation of downstream signalling cascades.

6. Cellular response.

7. Signal termination.

What happens during ECR autophosphorylation?

Specific tyrosine residues on the receptor's intracellular domain are phosphorylated, creating docking sites for adaptor proteins

What are examples of downstream signaling cascades activated by ECRs?

RAS-MAPK Pathway: Regulates gene expression and cell proliferation.

How is ECR signalling terminated?

receptor dephosphorylation, internalization, or degradation to prevent overstimulation

Why are receptor tyrosine kinases (RTKs) significant drug targets?

• Overactivation of RTKs promote tumour growth and metastasis.

• Drugs targeting RTKs include monoclonal antibodies (e.g., trastuzumab for HER2) and tyrosine kinase inhibitors (e.g., erlotinib for EGFR).