Cell Communication Flashcards
(29 cards)
What does vasopressin do to the kidney
Vasopressin (ADH) is received by the cells of the kidney that form the collecting duct which takes the urine and moves it to the ureter
when cells of the collecting duct receive a signal what do they do
do exocytosis of secretory vesicles that have aquaporins so that the aquaporins can put water into the bloodstream from the collecting duct
what two things can be wrong with a diabetes insipidus person who can’t respond to ADH
1) they can have defects in the ADH receptor
2) defects in aquaporins so that they never get into the secretory vesicles
Nuclear response
changes in gene expression and is slow and long-lasting
cytoplasmic response
no change in gene expression, fast but temporary
what is an intracellular steroid receptor
a steroid receptor inside the cell cytoplasm
how does intracellular steroid receptor work
receptor binds to steroid and is activated, enters nucleus and gene expression is changed (nuclear response)
steroids are hydrophobic so can diffuse through membrane
Ligand gated ion channels
ligand binds to and opens up an ion channel (the neurotransmitters are the ligands)
which mechanisms use molecular switches
G proteins and kinase receptors
What are G proteins
G proteins are GTPases that hydrolysze GTP to GDP +P
when is a g protein on or off
when it is bound to GTP it is on, when it is bound to GDP it is off
What is a GEF
protein that turns on G protein - they make the drop GDP and pick up GTP
what turns off g proteins
GAP - g protein hydrolyzes GTP to GDP
what do tyrosine kinase receptors do
use phosphorylation of tyrosine amino acids to turn on signaling pathway
kinase
enzyme that adds a phosphate group to another protein (phosphorylation) to turn it on
phosphatases
enzyme that removes phosphate groups, turns a protein off
structure of tyrosine kinase receptor
transmembrane protein with tyrosine amino acids, binds to ligand making two receptors bind to each other and they phosphorylate each other, relay proteins bind to these and become activated and initiate the signal transduction pathway
function of signal transduction
connects function to response
purpose of using a signaling cascade
to amplify the signal and is regulatory (can remove a part of cascade)
how does a phosphorylation cascade work
kinase 1 is phosphorylated and activated, Kinase1 phosphorylates kinase 2…etc
what is a second messenger
a small non protein hydrophilic signaling molecule (ions, etc)
how is IP3 made
by cutting PIP2 ( a phospholipid in plasma membrane inside cell) using phospholipase C,
what does IP3 do
it can diffuse into cytoplasm and send signals
function of released IP3
IP3 binds to ligand gated sodium channels in the SER and makes them opened, Ca2+ released binds to proteins
