cell signaling/communication Flashcards
bacteria communication
chemical system called “quorum sensing”
eukaryotic communication
coordinates activity
chemicals are the signals
source and receiver are both cells
responses to cell communication
change in gene expression, anabolic or catabolic states, etc.
Ligand
a signaling molecule highly specific to a particular receptor
signal reception process
a ligand binds to a receptor protein, causing shape change
2 types of receptors
intracellular, plasma membrane proteins
intracellular receptors
uses blood stream to get into cell
hydrophobic molecules
(hormones, steroids, etc)
plasma membrane proteins
most receptors (GCPR’s, RTK’s, T cell’s, etc)
where are intracellular receptors located
in the cytoplasm of target cells
membrane protein signal reception uses what receptors
G-protein coupled receptors (GCPR’s)
GCPR function
catalyzes chemical reaction, binds w signaling molecule that activates a G protein, G protein activates enzyme
Can a G-protein turn off
yes, it phosphorylates itself
what would happen is a G protein never turned off
the activated enzyme would never deactivate which would cause constant cell division (aka cancer)
protein phosphatases and kinases
phosphatase- unphosphorylates something
kinase- phosphorylate something
Tyrosine Kinases process
causes something to become phosphorylated after coming together and changing shape which causes it to phosphorylate and then phosphorylate other enzymes
tyrosine kinase function
catalyzes the transfer of phosphate groups from ATP to another protein
what functional group allows the protein phosphorylation
hydroxyl group
Ion channel (ligand gated)
channel protein that is closed till a ligand causes channel to open, then closes once ligand leaves
Signal transduction process:
occurs in cascades
consists of many different relay molecules
relay molecule gets activated which activates the next one
Why use a cascade?
it amplifies a signal
cAMP, IP3, and calcium ions are considered what?
second messangers
what are second messangers
small, non-protein, water soluable, molecules or ions that spread out by diffusion
why use a second messanger?
they can be mass produced for very cheap and it amplifies signals
cAMP function
turns ATP into AMP due to 2 phosphates being cut off
what enzyme converts ATP to AMP
adenylyl cyclase
