March 13 Flashcards
Which subunit only of AMPK is responsive to the long chain FA-CoAs? What module is used by them to bind?
It is the B1 subunit of AMPK. Binding to carbohydrate binding module (CBM)
What is the kinase that PO4’s AMPK, does it need T-loop PO4 for it to be active? It is in complex with what 2 other subunits? One of these subunits is needed for staying active as it does what? This complex is a known ________ suppressor.
It is LBK1. It is in complex with STRAD (pseudokinase) and MO25. STRAD binding to LKB1 heeps it it in the active conformation, so once AMPK has conformational change by binding to AMP, it is a good substrate for LBK1. Tumor suppressor. LKB is not phosphorylated on T loop, it is in active conformation because of STRAD.
AMPK activation inhibits protein synthesis via inhibition of the _______ pathway and activation of ________ kinase.
TOR pathway, and elongation factor 2 kinase (eEF2)
What does phosphorylation of eEF2 by the eEF2 kinase do to it?
It inactivates it, so ribosome will stall
Describe pathways that join into one for stress and growth factors.
For stress: Have AMPK binding to AMPK from low energy, then LKB1 (always in active conformation) is able to PO4 AMPK so now it is active. Then AMPK will PO4 TSC2, the GAP (Gtpase activating protien) for RHEB, a small G protein that activates TOR kinase. Because GAP is active RHEB remains GDP bound (inactive)
Then have growth factor pathway, that will do te PIP3 and PDK1 thing, then PKB will PO4 TSC2 ON A DIFFERENT SITE, this time INACTIVATING THE GAP, so now RHEB will stay bound to GTP and be active, so activate TOR pathway
Glycogen is in most cells, but especially abundant in mammals in ______ and ______
Muscle and liver
For TSC2 that is GAP for RHEB, what does TSC stand for?
For Tuberous sclerosis complex
What is TOR (in 3-4 words).
It is Ser/Thr kinase.
What form is glucose converted to so it can be added to chain and form glycogen? What enzyme adds the glucose to chain?
It is UDP glucose, then added by glycogen synthase
What converts Glucose-1-phoshpate to G6P?
It is phosphpoglucomutase
What are the fates of G6P once produced by the breakdown of glycogen?
It is hydrolysis by phosphatase to glucose that goes to blood. Or it goes through glycolysis to make ATP
When have adrenalin, what happens that gets glycogen breakdown to start?
First have elevated cAMP, then get PKA activation. Then dephosphoyrlation of different things that will help break down glycogen. If these enzymes are phsophorylated they are inactive
G6P activates glycogen ______ and inhibits glycogen __________. These are enzyme names.
Activates glycogen synthase and inhibits glycogen phsophorylase
What phosphatase is allosterically activated by AMP to degrade glycogen in skeletal muscle?
Phosphatase B
Glycogen synthesis is initiatied by covvalent attachment to a protein called ____ on a ______ residue?
Glycogenin, and glucose added to tyrosine residue
What enzyme breaks down glycogen? Turns it into what?
Glycogen phosphorylase, it turns it into glucose-1-phosphate.
