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What is the role of insulin and how does it help your body regulate blood glucose when eating a meal such as this apple your body will begin breaking it down so that it can absorb its nutrients in the small intestine here the bite of the apple travels through the stomach and into the small intestine right next to the small intestine and stomach we can find the pancreas
Let us zoom into this area here one of the final products of food digestion is glucose commonly known as sugar glucose is absorbed from the small intestine into your blood as a result we have high blood glucose levels this will stimulate the pancreas to release the hormone insulin into the bloodstream insolent targets many cells to promote the clearance of glucose
From the blood defects in this process can be catastrophic as we often see in individuals with type 1 diabetes who lack the ability to make insulin insulin targets cells such as skeletal muscle cells liver cells and fat cells let us look at the fat cell in more detail and the effects insulin has on it the fat cells have insulin receptors on its cell surface insulin
Binds to these receptors in a very precise way which triggers a sequence of events to occur inside the cell a cascade of events which will lead to a number of outcomes these outcomes include the uptake of glucose and promoting glucose storage in the form of glycogen in fat cells insulin promotes a glucose storage in the form of lipids inhibits the breakdown of lipids
Stimulates protein synthesis and modifies gene expression overall insulin promotes energy storage within fat cells promoting the clearance of glucose from the blood returning blood glucose back to normal importantly when insulin binds to the receptor the multiple processes that occur within the fat cell are not all turned on at once insulin regulates the multiple
Processes using protein phosphorylation protein phosphorylation is a normal chemical reaction that changes the behavior of proteins inside the cell thus by using protein phosphorylation the cell can select which processes to turn on or off and when researchers can study protein phosphorylation in cells using a technique called mass spectrometry recent studies
In the fat cell reveal that following insulin stimulation many thousands of changes in protein phosphorylation occur but importantly they do not occur simultaneously some happen rapidly others more slow some go up and others go down to unravel this complexity they have recently developed a tool known as the monado plot as a way to visualize this complexity let us
Learn more about what this tool can reveal here is a fat cell this is a cell’s plasma membrane inside the cell there is a nucleus which contains the dna our genetic material surrounding the nucleus is the cytoplasm at rest our body requires energy to function the fat cell serves as an energy reserve breaking down its lipids releasing fatty acids into circulation
And these can be used for energy in other organs such as the heart after a meal insulin is released and binds to insulin receptors on fat cells this triggers a cascade of phosphorylation events inside the cell that leads to a number of outcomes occurring at different times here we will look at a timeframe from zero seconds to twenty minutes following the binding
Of insulin to the insulin receptor the insulin phosphorylation cascade leads to the inhibition of lipid breakdown beginning right away by 30 seconds it stimulates glute 4 glucose transporters to make their way to the surface of the cell by 5 minutes glute 4 is highly active on a plasma membrane glue 4 allows the high amounts of glucose outside the cell to move
Inside the cell by 20 minutes the cascade of phosphorylation events stimulates glucose storage this is done by storing glucose as glycogen through glycogenesis and particularly in fat cells storing glucose as lipids through lipogenesis moving back another separate cascade of events stimulates protein synthesis and modification of gene expression to modify gene
Expression certain proteins are activated in the cytoplasm of the cell some of these reactions occur within seconds and some within minutes this activated protein is now able to move inside the nucleus and can now interact with the dna to modify gene expression by examining changes over time researchers are now able to piece together the precise order of events
That the fat cell performs to take up glucose in response to insulin one can imagine that if this cell did not respond to insulin properly it would not be able to process the glucose properly leading to the onset of type 2 diabetes to understand diseases like diabetes it is crucial now to understand its underlying complexity and to utilize sophisticated ways like
Minato to visualize the data in a relatively simple way you
Transcribed from video
Insulin Signalling Pathway Minardo By Armando Hasudungan
