Term
| Signal Transduction Pathway |
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Definition
| A series of steps linking a mechanical, chemical, or electrical stimulus to a specific response. |
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Term
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Definition
| A secreted molecule that influences cells near where it is secreted. |
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Term
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Definition
| In multicellular organisms, one of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the body, changing the target cells' functioning. Horomones are thus important in long-distance signaling. |
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Term
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Definition
| A molecule that binds specifically to another molecule, usually a larger one. |
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Term
| G Protein-Coupled Receptor (GPCR) |
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Definition
| A signal receptor protein in the plasma membrane that responds to the binding of a signaling molecule by activating a G protein. Also called a G protein-linked receptor. |
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Definition
| A GTP-binding protein that relays signals from a plasma membrane signal receptor, known as a G-protein coupled receptor, to other signal transduction proteins inside the cell. |
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Term
| Receptor Tyrosine Kinases (RTK) |
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Definition
| A receptor protein spanning the plasma membrane, the cytoplasmic (intracellular) part of which can catalyze the transfer of a phosphate group from ATP to a tyrosine on another protein. Receptor tyrosine kinases often respond to the binding of a signaling molecule by dimerizing and then phosphorylating a tyrosine on the cytoplasmic receptor of the other receptor in the dimer. The phosphorylated tyrosines on the receptors then activate other signal transduction proteins within the cell. |
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Definition
| A transmembrane protein containing a pore that opens or closes as it changes shape in response to a signaling molecule (ligand), allowing or blocking the flow of specific ions; also called an ionotropic receptor. |
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Definition
| An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein. |
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Term
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Definition
| An enzyme that removes phosphate groups from (dephosphorylates) proteins, often functioning to reverse the effect of a protein kinase. |
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Term
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Definition
| A small, nonprotein, water-soluble molecule or ion, such as a calcium ion (Ca2+) or cyclic AMP, that relays a signal to a cell's interior in response to a signaling molecule bound by a signal receptor protein. |
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Term
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Definition
| Cycline adenosine monophosphate, a ring-shaped molecule made from ATP that is a common intracellular signaling molecule (second messenger) in eukaryotic cells. It is also a regulator of some bacterial operons. |
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Term
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Definition
| An enzyme that converts ATP to cyclic AMP in response to an extracelluar signal. |
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Term
| Inositol Triphosphate (IP3) |
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Definition
| A second messenger that functions as an intermediate between certain signaling molecules and a subsequent second messenger, Ca2+, by causing a rise in cytoplasmic Ca2+ concentration. |
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Definition
| A second messenger produced by the cleavage of the phosphoipid PIP2 in the plasma membrane. |
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Term
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Definition
| A type of large relay protein to which several other relay proteins are simultaneously attached, increasing the efficiency of signal transduction. |
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Term
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Definition
| A type of programmed cell death, which is brought about by activation of enzymes that break down many chemical components in the cell. |
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