Biosignaling through receptor tyrosine kinases Flashcards
in the first step of the MAPK pathway, once insulin binds to the receptor, autophosphorylation on which AA residue occurs??
autophosphorylation on the TRY residues
describe how to use rigRRmet to remember the MAPK pathway
r- receptor i-IRS-1 g- Grb2 R-ras R- raf-1 m-MEK e- ERK t- transcription factors
what are the two major pathways activated by receptor tyrosine kinase
MAPK and PIP3
how does RAS get activated?
when Grb2 and sos bind to it, GDP gets displaced with GTP and it is activated
what does activated RAF-1 do to MEK?
phosphorylates it with 2 P on its Ser residues
what does insulin receptor do to IRS-1
phosphorylates it on thy residues
what does Grg2 do to IRS-1
binds to P on IRS-1
what does RAS do to RAF-1
activates it
what does MEK do to ERK
phosphorylates it
describe a quick overview of signaling through PIP3 pathway
1) activated IRS-1 binds to PI3K ( activating it)
2) PI3K converts PIP2 into PIP3
3) PKB bond to PIP3 is activated
4) PKB phosphorylates GSK3 –> INACTIVATING IT!
5) GS ( glycogen synthase ) remains active
6) synthesis of glycogen from glucose is accelerated
7) PKB stimulates GLUT4 to uptake more glucose
what is funky about the phosphorylation of GSK3?
when phosphorylated, GSK3 is INACTIVE,
when GSK3 is inactive, it cannot convert GS to its inactive form ( also done by phosphorylation ) so GS stays active ( with no P)
is there cross-talk between tyrosine receptor proteins and GPCR?
yes, such as RTP phosphorylating the ser residue on Gsby, allowing B-arrestin to bind and endocytosis to occur
what does a kinase do, what does it need and how does structure aid in this?
phosphorylates an accepting protein on AA such as Ser, try, thr. It adds a phosphate from ATP
it has a n- terminus, c-terminus and catalytic cleft
what is the resting membrane potential?
-70 to -50 mv
in a sodium-potassium pump what gets pumped in and what out?
3 Na+ out and 2K+ inside
