Various cell surface receptors

Cell surface receptors, also called transmembrane receptors, are specialized proteins embedded in the plasma membrane that bind extracellular ligands (such as hormones, neurotransmitters, and growth factors) to transmit signals into the cell, triggering intracellular signaling cascades and cellular responses. There are three principal families of cell surface receptors: G protein-coupled receptors (GPCRs), ion channel receptors, and enzyme-linked receptors (such as receptor tyrosine kinases); each plays a critical role in regulating processes like metabolism, proliferation, and immune defense and is a key target class in drug development

Other names

Transmembrane receptorCell-surface receptorMembrane receptorSurface antigen

Agonism (activating ligand binds receptor) Antagonism (inhibitory ligand blocks receptor) Allosteric modulation (modifies receptor response) Enzyme inhibition (for enzyme-linked receptors) Channel blocking/opening (for ion channel receptors)