Cell Communication 2 Flashcards
What does adenylyl cyclase do?
generates cAMP which then goes on to interact with its target protein to cause a biological response
GPCR attaches to _____
G alpha q or G alpha o
Phospholipase C cleaves a membrane protein called ______
PIP2
What does PIP 2 produce?
IP3 and DAG 2nd messengers
IP3 triggers release of _______ from _________
Ca2+; endoplasmic reticulum
How does IP3 trigger the release of calcium?
by binding to an IP3 gated Ca2+ channel and triggers opening
Both ____ and DAG bind to another protein kinase called protein _______
Ca2+; kinase C
What happens after conformational change occurs in PKC?
it is activated
What does PKC phosphorylate?
a variety of membrane and cytoplasmic substrates
What role does receptor tyrosine kinase (RTKs) play?
signal transduction
RTKs have what type of receptors?
enzyme linked
RTKs are used for response to growth factors: mediated _______
growth factor signals
What is EGF?
epidermal growth factor
What is PDGF?
platelet derived growth factor
What is NGF?
nerve growth factor
What is FGF?
fibroblasts growth factor
What is IGF-1?
insulin like growth factor 1
What does the cytoplasmic domain of RTKs do?
transmit signal through tyrosine kinase domain
adds phosphate to tyrosine on proteins
When ligands bind to the receptor tyrosine kinase, what happens?
conformational change
induces dimerization of two receptor monomers
autophosphorylation occurs
When the receptor tyrosine kinase autophosphorylates the site, what does this cause?
the receptor to act as a scaffold or docking site to recruit other proteins to plasma membrane
Receptor tyrosine kinase does bind to _______ protein but to proteins with domain called ________ domain, which binds to phosphotyrosine.
G; SH2
What is SOS?
son of seven less, fruit flies have omatidia (R1-R8). When R7 is knocked out, the fly can live and not detect UV
What is the ligand of receptor R7?
Boss= bride of seven less
What are the two proteins down stream of the R7 receptor?
SOS and Grb2
What is the process of JAK-STAT?
- ligand binds to receptor
- JAKs phosphorylate each other and receptor
- Receptor binds and phosphorylates STATs
- STATs separate from receptors, dimerize and enters nucleus to bind to DNA and cause transcription of target genes
______ employs JAK-STAT to initiate signaling
erythropoietin
What is the process of serine threonine receptor and Smad?
- activated receptor binds to R-smad and phosphorylates R-smad
- R-smad binds to Co-smad and moves into nucleus to impact transcription of target genes
What is heredity hemochromatosis?
diseases with uncontrollable iron absorption
What does DMT1 do?
transfers iron into intestinal cell
What does ferroportin do?
iron out of intestinal cell and into blood
What is Hepcidin?
25 amino acid protein made in the liver with action in the intestine, regulator of iron homeostasis
Hepicidin binds to _____ which causes internalization of protein which is destroyed by proteolysis
ferroportin
When iron replete hepicidin expression is ____ and ferroportin levels are _____
up; down
What is the gene for hemochromatosis and how common is it?
HFE; autosomal recessive and 1/250 incidence
What is the mutation in HFE?
cys 282– tyr
If Hfe is mutated it cannot bind to _____. Which lead to what?
TfR2; cannot turn on hepcidin expression, no control of ferroportin activity
