Flashcards in cell communication Deck (51):
Does ligands (Extracellular signal molecules) bind to specific receptors?
yes they bind to specific receptor proteins
What is the concentration of of ligands?
They usually have a generally low concentration
What is the affinity for that receptors have for their ligands?
protein receptors have high affinity for their ligands
What type of protein receptor are exceptions to specificity binding of a ligand?
Gap junctions - they exchange small intracellular signaling molecules between cells
What is the general pathway of cell communication?
1) Extracellular ligand bind to protein receptor
2) intracellular protein are activated
3) intracellular proteins activates effector proteins
What are the different types of effector proteins?
metabolic enzyme - alters metabolism
gene regulatory protein - altred gene expression
cytoskeletal protein - altered cell shape or movement
What are the different types of cell communication?
Contact-dependent (membrane bound signaling)
What are the short distance forms of cell communication?
Contact-dependent (membrane bound)
What are the long distance forms of cell communication?
What type of communication is important in development and immune response?
Contact dependent (membrane bound)
Which types of cell communication secrets local mediator from receptors on the secretory cell itself?
What is endocrine signaling?
secretion of hormones into the blood.
widespread signal to targets that only recognize them
How fast is endocrine signaling?
very slow signal transduction
What is synaptic signaling?
signaling that arises from the synaptic contacts between nerve cells and specific targets in its signal
How fast is synaptic signaling?
very fast signal transduction
What is an advantage of the different cell communications?
each type takes different timeframes to produce a change within the cell.
How does each cell type work to respond to different signals?
each cell types have different receptors to direct down a specific path
signals molecules work in combinations to regulate the behavior of the cell (cell differentiation)
Why does the same signal molecule produce different responses in different cell types?
2) different intracellular pathway
What type of response does acetylcholine heart muscles?
decreased rate and forced contraction
Muscarinic receptor (mAchRs)
What type of response does acetylcholine produce in skeletal muscle?
Nicotinic receptors (nAChRs)
What type of response does acetylcholine produce in salivary glands?
What is another way that cell types can produce different responses?
different signal molecule concentrations
What defines the lifetime of an intracellular molecule?
signaling kinetics - the rate at which a molecule degrade depends what type of signaling pathway.
each have a different rate of signaling and half lives
What determines the rate of signals on and off?
What type of signal is NO?
What is the role of NO in vasodilaton?
cause smooth to relax (regulate blood flow)
What is the pathway of relaxation of smooth muscle?
Acetylcholine is released by nerve terminals and activates NO sythase (NOS) and produces NO in endothelial cells.
2) NO diffuse out of endothelial cells into smooth muscle cells where it binds to and activates guanyl cyclase to produce cyclic GMP
3) cyclic GMP triggers a response that cause the smooth muscle to relax, enhancing blood flow through blood vessel
What is a precursor to NO?
What are nuclear regulators?
ligand modulated gene regulatory proteins
What type of signal molecules are the ligands for Nuclear receptors?
generally bind to carrier proteins in body fluids
they bind to intracellular receptors (nuclear receptor family)
What are orphan nuclear receptors?
identified by DNA sequencing with no known ligands
What are the precursors for nuclear receptor ligands?
How does nuclear receptor superfamily bind to DNA?
they bind to DNA as a homodimer or heterodimer
Where does nuclear receptor dimer bind?
to a specific DNA sequences adjacent to the genes the ligand regulates (promoters)
Where are some nuclear receptor located and bind like cortisol?
some like cortisol receptors are located in the cytosol and enter the nucleus after ligand binding
Where are other nuclear receptors located and bind besides the cytosol?
thyroid and retnoid are bound to DNA
they change conformation after ligand binding
What type of response does nuclear receptors induce?
What is direct nuclear receptor response?
receptor and ligand bind to DNA and produce primary response proteins
What is indirect nuclear responses?
primary réponse produced proteins bind to DNA and produce secondary response proteins
What are the three major classes of cell surface receptors?
1) ion channel coupled receptors
2) G-protein coupled receptors
3) enzyme coupled receptors
Why are some relay proteins scaffolded?
to prevent cross talk to proteins close to it
with scaffolding you can create hundreds of different signals
What are second messengers?
small intracellular signaling molecules cAMP Ca2+ diaglycerol
What does relay protein in intracellular signaling do?
simply pass on message
What does Adaptor/scaffold/anchoring protein function as in intracellular signaling?
link messenger proteins without themselves conveying a signal
What does amplifier proteins coin intracellular signaling?
enzymes or ion channels that greatly increase the signal they receive
What is multiple amplification steps in a relay chain called?
a signaling cascade
What does transducer cells function as in intracellular signaling?
converts signal into different forms
example would be the enzyme that makes cyclic AMP. it both makes it and amplifies it (transducer and amplifier)
What are bifurcation proteins in intracellular signaling?
spread signal from one signaling pathway to another
What are integrator proteins in intracellular signaling?
receives more than one signals and integrates them to one before passing them on
What are modulatory proteins in intracellular signaling?
modulate signaling of other signaling proteins