AMPK Signaling Pathway: Regulation and Downstream Effects

hey guys welcome to another medical biochemistry lesson um in this lesson I'm going to be talking to you guys about uh thek signaling pathway and in this video I'm going to be talking about just an overview of the amk singling pathway so um just to beginning what isk uh so ampk um is also uh known as amp activated protein kisee and as the name suggests um it is regulated by amp um so uh adenosine mono phosphate and uh it's actually regulated um primarily by the ratio to ATP ratio so when uh that ratio increases uh

this uh this protein ampk will become activated and because it's activated by it's considered an energy sensor for the cell and um and again as I mentioned before it's activated during an energy depletion and it regulates many uh different processes in the cell and thus it is is known as the master regulator of energy metabolism so here we havek um there's a there's several things that actually activate amk um I'll just go over a few in this video um the first thing I want to say is uh amp is an activator VPK obviously another protein

um is known as lkb1 or liver kyes B1 and then another thing that uh that activates amk which is interesting um is exercise exercise is actually an activator ofk so now um what does amk actually do in the cell well amk um first off it's U it's a negative regulator of uh mtor signaling so Maman Target of rapy so it actually um phosphates and um inactivates a mtor um which itself is an activator of uh protein synthesis so ampk will actually suppress protein synthesis another thing it does is it activates UL one um UL one

is uh is an indispensable protein um involved in macro autophagy so umk actually um activates uluk one which will then activate autophagy so amk signaling leads to an activation of autophagy pathway another thing ampk does is it activates atgl um atgl is adpost triglyceride lipase and this is the uh the first enzyme um involved in the uh the the release of fatty acids from a triglyceride molecule um and that um obviously leads to a fatty acid catabolism uh and another thing that ampk does is it actually inhibits ACC or acial COA um carboxy ASE now

this this enzyme is is uh uh indispensable um for fatty acid fatty acid synthesis um so when amk actually inhibits ACC um it actually means it inhibits fatty acid synthesis so you can kind of see where this is going guys um APK activates fatty acid catabolism and oxidation and will um suppress fatty acid synthesis and then another thing that's um kind of closely related to fatty acid synthesis um is um HMG um HMG COA reductases and this is the the enzyme involved in cholesterol synthesis so ampk actually inhibits um hngg COA reduct a so it

thus inhibits cholesterol synthesis now um other things that ampk does is it actually will activate uh glucose uptake through glute 4 Transporters um through um the process um involving TB uh tbc1 D1 um so this is uh another way that um an insulin sensitive cell may be able to uptake glucose um independent of insulin signaling it can um actually go through an ampk dependent pathway um and this is exactly what happens um for instance in exercise um during exercise you can have um exercise activating APK which can then uh increase glucose uptake through glute for

um translocalization so this just leads to um uh increase glucose uptake and glycolysis and the last thing that I want to talk to you guys about is that ampk actually inhibits glycogen synthes um so it in actually inhibits glycogen synthesis so that makes sense right you the cell's taking up glucose um through um increasing glucose uptake but then it's actually inhibiting glycogen synthesis um through ampk so now just a summary of the ampk signaling pathway um the first thing um is that it is ampk once amk is activated it'll actually increase glucose uptake and utilization

another thing it does is it increases fatty acid oxidation uh through atgl another thing it does is it increases autophagy now it increases autophagy by a couple of different mechanisms as I mentioned Ulan but also its uh negative regulation of mtor actually um causes an increase in autofy as well now it um mpk actually decreases glycogen synthesis so um you can see here that glucose uptake and utilization increase but glycogen syn synthesis is decreased um NPK also um inhibits fatty acid synthesis and it inhibits um protein synthesis and cholesterol synthesis so you can see here

that um ampk is is uh NPK signaling is is leading to uh an uptake and utilization of nutrient utri um so uh it's utilizing the nutrients but it's utilizing them um in catabolism not in anabolism it's not utilizing the nutrients for synthesis it's actually utilizing the nutrients for for uh making more energy making more ATP and that's pretty much the bottom line guys the general statement is that ampk signaling leads to an increase in catabolism but a decrease in anabolism so the main goal for ampk signaling is to upregulate um Pathways to um decrease uh

energy expenditure while increasing energy um production so that the uh the the am to ATP ratio can reverse so you can get more ATP um and less am anyways guys that was uh an overview of amk signaling if you found this video helpful please like And subscribe that's always greatly appreciated