Term
| signal transduction pathway |
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Definition
| A series of steps linking a mechanical or chemical stimulus to a specific cellular 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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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 to change their functioning. |
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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 |
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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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Definition
| A receptor protein in 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 portion 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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Term
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Definition
| A protein pore in cellular membranes that opens or closes in response to a signaling chemical (its ligand), allowing or blocking the flow of specific ions. |
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Definition
| An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein. |
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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 (Ca) 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
| Cyclic 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
| adenylyl cyclase (uh-den′-uh-lil) |
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Definition
| An enzyme that converts ATP to cyclic AMP in response to a signal. |
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Term
| inositol trisphosphate (IP3) (in-ō′-suh-tol) |
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Definition
| A second messenger that functions as an intermediate between certain nonsteroid hormones and a third messenger, a rise in cytoplasmic Ca2+ concentration. |
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Term
| diacylglycerol (DAG) (dī′-a-sil-glis′-er-ol) |
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Definition
| A second messenger produced by the cleavage of a certain kind of phospholipid in the plasma membrane. |
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Term
| Apoptosis (ā-puh-tō′-sus) |
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Definition
| A program of controlled cell suicide, which is brought about by signals that trigger the activation of a cascade of suicide proteins in the cell destined to die. |
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