typesreceptor

Types of receptor refers to the diverse proteins that bind signaling molecules and translate extracellular or intracellular cues into cellular responses. Receptors are essential components of cell signaling and vary in location, structure, and mechanism of action. Most are located on the cell surface, but others reside inside the cell and respond to ligands that cross the membrane.

Membrane-bound receptors detect extracellular signals and initiate rapid or cascaded responses. Major families include G protein-coupled receptors (GPCRs), which activate heterotrimeric G proteins and generate second messengers such as cyclic AMP and calcium; receptor tyrosine kinases (RTKs), which phosphorylate tyrosine residues and trigger downstream cascades like MAP kinase signaling; and ligand-gated ion channel receptors, which control ion flow across the membrane to alter membrane potential and signaling. Additional families include cytokine receptors, which transmit immune and growth signals, and Toll-like receptors, which detect microbial components and activate inflammatory pathways.

Intracellular receptors bind ligands that cross the cell membrane, such as steroid hormones and thyroid hormones. These receptors often function as transcription factors or regulate transcription indirectly, producing longer-term changes in gene expression.

Receptor signaling is modulated by processes such as desensitization, receptor internalization, and downregulation, which help control sensitivity and duration of responses. Receptors are key drug targets, enabling therapeutic modulation of processes ranging from cardiovascular regulation to immune function and neurological signaling.