Question

How do the molecules that activate the vertebrate TLR signal transduction pathway differ from the ligands in most other signaling pathways (see Concept 11.2)?

Short answer

Since the ligand for the TLR receptor is a foreign molecule, unlike the ligand for many other signaling routes, the chemicals that activate the vertebrate TLR signal transduction pathway differ from the ligands for most other signaling pathways.

Step-by-step solution

Signaling pathway

Signaling pathways transport information from the outside to the inside of a cell, such as biological information. In most signaling pathways, transcription factor activity regulates gene expression (the amount of mRNA produced).

Ligands

Cells have signals that trigger certain processes to start or stop. These signals are called ligands. The molecules known as ligands help cells communicate with one another and internally. Ligands bind to receptors, which are biological proteins.

TLR

Innate immune cells, such as macrophages, have toll-like receptors on their surfaces. Toll-like receptors are unique because they detect pathogens (bacteria and viruses) and trigger the immune system's response to destroy them.

Cells often use a protein called a Toll-like receptor (TLR), which is related to the Toll protein present in insects. TLR proteins detect infections and trigger reactions specific to the invading microbe based on the signals they create.