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Tol-like receptors (TLRs) are a class of proteins that play a key role in the in

ID: 99562 • Letter: T

Question

Tol-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. They are non-catalytic receptors typically expressed in sentinel cells, such as macrophages and dendritic cells. TLRs recognize structurally conserved molecules derived from microbes. Once these microbes have breached physical barriers (such as the skin or intestinal tract mucosa) they are recognized by TLRs, which activate immune system responses. There is a large family of TLRs, each having different recognition abilities and many working together to recognize foreign molecules. Consider this overview of TLRs for the following questions.

Explanation / Answer

Fluorescence resonance energy transfer (FRET) is a mechanism describing eneegy transfer between two light sensitive molecules or chromophores. The efficiency of this energy transfer is inversely proportional to the sixth power of the distance between the donor and acceptor molecule. Thus effectively, FRET measures the distance between two flurophore molecules.