Receptors & Cell Signaling Flashcards
What does a ligand-receptor complex do?
It will activate or inhibit cellular pathways.
What do effectors do?
They alter the activity of different components downstream. They generate secondary messengers that elicit a particular cellular response such as enzymatic activity, gene expression, etc.
What are some examples of effector proteins?
Metabolic enzymes
Gene regulatory proteins
Cytoskeletal proteins
What is endocrine signaling
Signal transported via blood
Long-distance
Long-lasting
Freely diffusing signal
*epinephrine
What is paracrine signaling
Signal diffuses to a neighboring target cell of a different cell type
Local signaling
Short-lived
*testosterone.
what type of signaling does testosterone do
Paracrine. Leydig cells synthesize and secrete testosterone which induces spermatogenesis by acting on Sertoli cells
What is autocrine signaling
Secreting cells also express surface receptors for the signal
Can release to cells of the same type
Common in chemokines
*Interleukins
What is direct/juxtacrine signaling
Signal binds to signaling cell which then binds to the receptor on a target cell.
Close contact is required.
*Heparin-binding epidermal growth factor binds to EGF receptor
Are water-soluble signals hydrophilic or hydrophobic
Hydrophilic
Are lipid-soluble signals hydrophilic or hydrophobic
HYdrophobic
Where do hydrophilic signals interact w/ receptors?
At the cell surface because they cannot penetrate the plasma membrane. Ex. epinephrine, insulin, glucagon.
which receptors are involved with hydrophilic signals?
G-protein coupled receptors (GPCRs)
Receptor tyrosine kinases (RTKs)
Where do hydrophobic signals interact w/ receptors?
Lipophilic signals pass through the plasma membrane of the target cell and bind to receptor proteins inside the cell
Ex. steroid hormones, thyroid hormones, retinoids
which transcription factors are involved with hydrophobic signals
Cytoplasmic receptors (inactive when attached to HSP90, activates upon ligand attachment, HSP90 dissociates, hormone-receptor translocates to nucleus to interact w/ hormone response element)
Nuclear receptors (already present in nucleus bound to DNA)
To become active, what must happen to the inactive G protein?
It must exchange its GDP for GTP. The active GTP-bound alpha subunit will separate from beta and gamma subunits.
