G protein-coupled receptors

DEFINITION:

G protein-linked (or coupled) receptors mediate the cellular responses to an enormous diversity of signaling molecules, including hormones, neurotransmitters, and local mediators, which are as varied in structure as they are in function: the list includes proteins and small peptides, as well as amino acid and fatty acid derivatives.

Despite the chemical and functional diversity of the signaling molecules that bind to them, all of the G protein-linked receptors whose amino acid sequences are known from DNA sequencing studies have a similar structure and are almost certainly evolutionarily related. They consist of a single polypeptide chain that threads back and forth across the lipid bilayer seven times.

The members of this receptor family have conserved not only their amino acid sequence but also their functional relationship to G proteins by means of which they broadcast into the interior of the cell the message that an extracellular ligand is present.

hybrid

DEFINITION:

An animal or plant produced from parents different in kind, such as parents belonging to two different strains, varieties, or species.

receptors

DEFINITION:

See definitions under "receptor."

bind

DEFINITION:

To form a weak, reversible chemical bond, e.g., antigen to antibody or hormone to receptor.

J

DEFINITION:

Symbol for joule .

immunocytochemical

DEFINITION:

Pertaining to the application of immunochemical techniques, e.g., immunoperoxidase staining, to cytochemistry.

pharmacologically

DEFINITION:

Pertaining to pharmacology or to the properties and reactions of drugs.

mutant receptors

DEFINITION:

Molecular structures within or on the surface of cells which do not bind with the specific substance for which they are intended, or do not cause the specific physiologic effect that accompanies that binding. See receptor.

misfolded

DEFINITION:

Mistakenly or wrongly folded. See fold.

pharmacologically

DEFINITION:

Pertaining to pharmacology or to the properties and reactions of drugs.

point mutation

DEFINITION:

A mutation resulting from a change in a single base pair in the DNA molecule, caused by the substitution of one nucleotide for another.

altered

DEFINITION:

1. Having been made or become different.

2. Castrated; spayed.

3. Abbreviation for "alteration."

pharmacologically

DEFINITION:

Pertaining to pharmacology or to the properties and reactions of drugs.

relative

DEFINITION:

1. A thing having a relation to or a dependence upon another thing.
2. A person connected with another by blood or marriage.
3. Pertinent, relevant.
4. Not absolute or independent; comparative.
5. Expressed as the ratio of the specified quantity to the total magnitude or to the mean of all quantities involved.

G protein-coupled receptors

DEFINITION:

G protein-linked (or coupled) receptors mediate the cellular responses to an enormous diversity of signaling molecules, including hormones, neurotransmitters, and local mediators, which are as varied in structure as they are in function: the list includes proteins and small peptides, as well as amino acid and fatty acid derivatives.

Despite the chemical and functional diversity of the signaling molecules that bind to them, all of the G protein-linked receptors whose amino acid sequences are known from DNA sequencing studies have a similar structure and are almost certainly evolutionarily related. They consist of a single polypeptide chain that threads back and forth across the lipid bilayer seven times.

The members of this receptor family have conserved not only their amino acid sequence but also their functional relationship to G proteins by means of which they broadcast into the interior of the cell the message that an extracellular ligand is present.

permission

DEFINITION:

Formal consent; authorization.