reseptorien

Reseptorien are biomolecules that detect signals and convert them into cellular responses. They can be proteins located on the cell surface, within the cytoplasm, or in the nucleus. By binding specific ligands—such as hormones, neurotransmitters, odorants, photons, or temperature changes—reseptorien initiate signal transduction pathways that alter cellular activity or gene expression.

Major classes include cell-surface receptors such as G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs), and ligand-gated ion channels; enzyme-linked receptors; and intracellular receptors like nuclear receptors that bind lipophilic ligands. Sensory receptors, including photoreceptors in the retina and olfactory and taste receptors, detect environmental stimuli directly. Mechanosensitive channels also act as reseptorien by responding to physical forces.

Mechanisms of action typically involve conformational changes upon ligand binding, leading to second messenger signaling (for example, cyclic AMP, Ca2+, IP3, DAG) or direct regulation of transcription. The specificity of ligand–receptor interactions underpins precision in signaling networks and enables amplification, feedback, and integration of multiple signals.

Reseptorien play essential roles in development, homeostasis, perception, immune responses, and physiology. They are central to pharmacology, as many drugs act as agonists or antagonists at specific receptors, producing therapeutic effects or side effects. Research on reseptorien uses binding assays, structural biology, and functional studies to understand signaling pathways and to develop targeted therapies.