Toll-like receptor

Toll-like receptors (TLRs) are type I transmembrane proteins that serve as a key part of the innate immune system. In vertebrates, they are also able to stimulate activation of the adaptive immune system, linking innate and acquired immune responses. TLR are considered pattern recognition receptors (PRRs), binding to pathogen-associated molecular patterns (PAMPs), small molecular sequences consistently found on pathogens. Their function is the recognition of pathogens and the activation of immune cell responses directed against those pathogens.

Related Topics:
Transmembrane protein - Innate immune system - Vertebrates - Receptors - PRR - Pathogen - PAMP - Cell

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First discovered in the fruit fly Drosophila melanogaster, TLRs are present in mammalian immune cells as well as in numerous other animals (including goldfish and chickens). They have even been found in plants and are thus believed to have an ancient evolutionary origin; after the defensins, they may be the oldest components of the immune system.

Related Topics:
Fruit fly - Drosophila melanogaster - Mammal - Goldfish - Chicken - Plant - Defensins

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Their name derives from sequence homology to the Drosophila melanogaster gene Toll. ("Toll" is German for "amazing" or "mad".) In flies, Toll was first identified as a gene important in embryogenesis in establishing the dorsal-ventral axis. In 1996, Toll was found to have a role in the fly's immunity to fungal infections. Toll-like receptors in mammals were identified in 1997.

Related Topics:
Sequence homology - Toll - German - Embryogenesis - Dorsal - Ventral - 1996 - Immunity - Fungal - Infection - 1997

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