Cell Communication

The strengthening of stimulus energy during transduction.

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.

water soluble ligand molecule; A catecholamine that, when secreted by the adrenal medulla, mediates "fight-or-flight" responses to short-term stresses; also released by some neurons as a neurotransmitter; also known as adrenaline.

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.

A type of intercellular junction in animals that allows the passage of materials between cells.

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

A molecule that binds specifically to another molecule; often first step in cell communication. Water soluble ligands typically do not enter cell. Lipid soluble ligands (such as steroids) do enter the cell.

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.

A secreted molecule that influences cells near where it is secreted. Used in paracrine and synaptic signaling.

An enzyme that transfers phosphate groups from ATP to a protein, thus phosphorylating the protein.

An enzyme that removes phosphate groups from (dephosphorylates) proteins, often functioning to reverse the effect of a protein kinase.

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.

The linkage of a mechanical, chemical, or electromagnetic stimulus to a specific cellular response.

A steroid hormone required for development of the male reproductive system, spermatogenesis, and male secondary sex characteristics; the major androgen in mammals. Pathway illustrates the mechanism for all steroid hormones.

A regulatory protein that binds to DNA and affects transcription of specific genes. The hormone-receptor complex becomes a transcription factor in the steroid transduction pathway.

reception - receptor responds to binding of ligand molecule; transduction - translation and amplification of message; response - activation of cellular response

receives message for g-linked protein signaling pathway. Consists of seven alpha helices that span the plasma membrane. Changes shape when ligand molecule binds.

The process by which a signal on a cell's surface is converted into a specific cellular response.

These regulators influence cells in the vicinity of them.

Circulating chemical signals that are formed in specialized cells, travel in body fluids, and act on specific target cells.

A molecule that specifically binds to another molecule, often a larger one.

The enzyme that transfers phosphate groups from ATP to protein.

Enzymes that can rapidly remove phosphate groups from proteins.

The target cell's detection of a signal molecule coming from outside the cell.

The binding of the signal molecule changes the receptor protein in some way.

The transduced signal finally triggers a specific cellular response.

A plasma membrane receptor that works with the help of a G-protein.

A receptor with enzymatic activity that can trigger more than one signal transduction pathway at once, helping the cell regulate and coordinate many aspects of cell growth and reproduction.

Type of membrane receptor that has a region that can act as a "gate" when the receptor changes shape.