Cell Communication Flashcards
Bacteria Communication
bacteria colonies have a small peptide, when in low bacteria conc, its conc is low too.
receptors on surface of organism to recieve signaling molecule
Signaling peptide: 17 peptides
As bacteria grow, signaling molecule conc incs, more likely to interact with receptor on cell surface
allow DNA molecs to be taken up by cells
receptor recieves signal, turn on genes, express proteins, bring DNA in from environment
Elements for Cell Cell Comunication
Signaling cell
signalling molec
receptor molec
receptor cell
When signaling molec recieved
recptor turned on
Steps of signaling
receptor activation (molec binds signal, conf change)
Signal transduction
Response
Termination
Signal transduction
conversion of signal from one form to another as its transduced from where its recieved to final response
environment
other cells
Receptors are
highly specific to specific signal molecules
Endocrine transmission
furthest distance
molecules travel through blood stream
signalling cell releases signaling molecule
estrogen/testosterone (hydrophobic, made from lipids, can diffuse right through membrane)
Paracrine transmission
diffusion over shorter distance
cells close to each other
embryonic development
Growth Factors
autocrine transmission
cell signaling itself (immune)
embryonic development, maturing cell types for immune system
juxtacrine transmission
2 cells in physical contact signal each other
transmembrane protein embedded in one cell interacts with that of an adjacent cell
tells you where you are in relation to other cells
Nervous system
Kholer and Limptom
grew fibroblast cells, gave them either plasma (unclotted blood) or serum (clotted blood).
look at density grown in either
more in the one with serum
Platelets: cause clotting
something released from platelets a possible growth factor.
then grew with just platelet proteins, so proved this.
signaling molecule is PDGF (platelet derived growth factor
Notch (nervous, juxtacrine)
become Glial Cells
Delta (nervous, juxtacrine)
become neurons
ligand
signaling molecule
Ligand binding site
receptor where ligand binds
specific affinity for the ligand
can bind tight and be kept for a long time or not
cell surface receptor
polar molecules
cant pass through PM
signal recieved at surface of cell on PM
conf change in receptor, once bound transduces signal
Intracellular Receptor
small, non polar signaling molecs
can pass through PM (also hydrophobic)
recieved by signaling molec in cytoplasm
conf change in molec, transduction
When receptor has bound signaling molec
turned on
if not bound, turned off
G-protein coupled receptors
G protein on cytoplasmic side
inteacts with receptor embedded in membrane recieving signal from outside.
Conf change in receptor allows it to interact with G protein
G protein changes from GDP to GTP
when GTP: ACTIVE, interacts with another molec, interact with other molecs and up regulate
most drugs
Receptor Kinases
adds a phosphate group to a molecule (phosphorylation)
turn molec on
ligand bound to receptor
receptors go under dimerization (receptors interact with each other once bound)
signal transduced
Ligand Gated Ion Channels
bind ligand to receptor pathway opens inos flood into cell can change electrochemical signal transduction
G Protein Activation
3 subunits, alpha beta and gamma
alpha bound to GDP or GTP
conf change makes alpha have a conf change and go for GTP
change conf again, lose beta and gamma sub units
adding phosphate is adding a slight negative charge
goes off to interact with other molecules after beta and gamma lost
second messengers
signaling pathway molecs tht arent proteins, water soluble, not first receptor
Calcium, cAMP, cGMP
amplification
when activated receptor turned on, it can interact wit LOTS of G proteins
G proteins interact with LOTS of adneyl cyclases
each of these catalyzes LOTS of transitions from ATP to cAMP,
activating protein kinase A
kinase A amplifies
