effector

1. C. Sherrington term for a peripheral tissue that receives nerve impulses and reacts by contraction (muscle), secretion (gland), or a discharge of electricity (electric organ of certain bony fishes). 2. A small metabolic molecule that by combining with a repressor gene depresses the activity of an operon. 3. A small molecule that binds to a protein and, in so doing, alters the activity of that protein. 4. A substance, technique, procedure, or individual that causes an effect. [L. producer]

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ef·fec·tor i-'fek-tər, -.tȯ(ə)r n

1) a bodily organ (as a gland or muscle) that becomes active in response to stimulation

2) a molecule (as an inducer, a corepressor, or an enzyme) that activates, controls, or inactivates a process or action (as protein synthesis or the release of a second messenger)

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n.

any structure or agent that brings about activity in a muscle or gland, such as a motor nerve that causes muscular contraction or glandular secretion. The term is also used for the muscle or gland itself.

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ef·fec·tor (ə-fekґtər) 1. an agent that mediates a specific effect, e.g., an allosteric effector or an effector cell. 2. an organ that produces an effect, e.g., contraction or secretion, in response to nerve stimulation. Called also effector organ.