Week 7_Cell-cell communication Flashcards
cells that are talking put out…
ligands
what are ligands?
signaling molecules that talking cells put out
cells that are listening have…
a receptor that the ligand attaches to
what does the ligand/receptor complex do?
transmits the signal into the target cell –> the target cell responds
___ leads to a cellular response
signal transduction
ligand/receptor complex ___ (transmits) the signal into the cell
transduces
what are some examples of types of cellular responses?
altered metabolism
altered gene expression
altered cell shape or motility
the responding cell is called the ___
target cell
does every cell respond to every signal?
no;
only the target cell with the proper receptor will respond to a particular ligand
there are ___ categories of cell signaling?
5
the 5 categories of cell signaling are based on:
the distance b/n the cells that are communicating
the type of cells that are communicating
what are the 5 categories of cell signaling?
autocrine signaling
direct cell-to-cell contact
paracrine signaling
endocrine signaling
synaptic signaling
what is autocrine signaling?
cell signaling to itself
what are examples of autocrine signaling?
immune cells – stimulate and amplify their own response to infections
cancer cells – stimulate their own growth and mobility
elaborate direct cell-to-cell contact
surface ligand on one cell touches surface receptor on the next cell
direct transmission of ligands thru gap junctions b/n cells
what are examples of cell-cell interactions?
cell-cell interactions play a critical role during:
embryonic development
wound healing
what is paracrine signaling?
cells signaling to nearby cells
what are examples of paracrine signaling?
ligands released at injury sites to stimulate an immune response and wound healing
embryonic development – development of the spinal cord
what is endocrine signaling?
systemic (organism wide) signaling via the circulatory system
what is an example of endocrine signaling?
hormones – released into bloodstream
stimulate development and maintenance of the reproductive system
what is synaptic signaling?
signal by a nerve cell thru a synapse to another cell or a responding cell
what is an example of synaptic signaling?
neurotransmitters – signaling molecules sent from a nerve cell to another nerve cell or a responding cell (a muscle cell)
what are the 2 types of signaling molecules (ligands)?
non-circulating ligands
circulating ligands
what are circulating ligands?
circulate thru the blood or other bodily fluids
what are the 2 types of circulating ligands?
non polar (hydrophobic)
polar (hydrophilic ligands)
what are examples of hydrophobic ligands?
hormones
- can diffuse across the plasma membrane
- hydrophobic ligands bind to intracellular receptors
- intracellular receptors transmit the signal
- cell responds
can hydrophilic ligands diffuse across the plasma membrane?
no; they are polar
hydrophilic ligands must bind to ___, which have ___
membrane-bound receptors
3 protein domains
what are the 3 protein domains on membrane bound receptors?
(1) an extracellular ligand binding domain (binds to ligand)
(2) transmembrane domain (goes thru the plasma membrane)
(3) intracellular signaling domain (transduces the signal)
many drugs ___ receptors
target (bind to)
drugs can be ___ or ___
agonists or antagonists
what are agonists?
mimic actions of ligand (activates receptor)
what are antagonists?
bind to but do not activate a receptor
they block ligands from binding to the receptor
what are examples of agonists?
drugs that activate the opioid receptor
what is naloxone/narcan?
opioid receptor antagonist
outcompetes agonists for binding to the opioid receptor
blocks the effects of drugs such as heroine and other opioid agonists
other medical uses for receptor antagonists include…
antihistamines
beta blockers
in cancer therapy
what do antihistamines do?
block the activity of histamine receptors to lessen the immune response
what do beta blockers do?
block some receptor sites for adrenaline to control blood pressure
explain receptor antagonists in cancer therapy?
many cancer therapy drugs that block receptors important to cancer cell growth and metastasis
