hey friends and welcome to today's video about the pi3k act m2a pathway this pathway leads to the activation of mTOR which will have positive effects on cell cycle progression cell survival and cell proliferation this pathway is actually often disturbed in cancer cells please keep in mind that mTOR has a lot of effect in the whole cell and in this video I will just touch the basics so the pathway basically starts with the molecule called pi3 kinase short pi3k we can see here that pi3k leads to the activation of act and also here in the side
branch we see that there is a protein called p10 which can inhibit this activation of act p10 is very well known and studied tumor suppressor gene but for simplification we will just exclude it here pi3 kinase will activate act and act can then lead to the activation of mTOR to name just two main effects of mTOR we have up regulated cell growth and mTOR also promotes cell cycle progression due to protein synthesis how is this whole pathway activated here I show you two possibilities it has been shown that the pi3k pathway can get activated by
the Rast gdp a.s however in this video we will focus on the activation of the receptor tyrosine kinases these membrane bound receptors can do two transfer station lead to the activation of pi3 kinase for the initiation of this pathway it is required that we have growth factors so they will bind you to our ligand binding sites this leads to the dimerization so the receptors form a dimer and one receptor will phosphorylate the tyrosine residue on the other one this transfers relation now allows for the docking of proteins and one of these proteins which get activated
by the tyrosine kinase is pi3k the purpose of our 3-kinase is to transform the pip2 which is a membrane protein binding to phosphates into pip3 the transformation of pip2 to pip3 activates pip3 and pip3 activates act now act can now initiate downstream effects and will activate mTOR and mTOR to make it short will up regulate the translation so the synthesis of proteins from mRNA it will further for example also initiate the biosynthesis of lipids so let's have a look at the main effect of mTOR this is firstly the cell survival the pi3k act mTOR pathway
will inhibit apoptosis so mTOR activation promotes cell survival further due to lipid and protein synthesis the cell can grow and the main point is that mTOR activation leads to cell cycle progression these proteins which are synthesized due to enter activation are involved in the cell cycle so the cell cycle can go on you can already imagine that if the emptor pathway is disturbed or let's say up regulated this can easily lead to uncontrolled cell divisions which can cause cancer lipid protein and amino acid synthesis which is definitely up regulated by the mTOR pathway can also
be summarized as anabolism in general the mTOR activation has anabolic effects on the cell that's it for today I hope it was very helpful for you please keep in mind that in this pathway there's a lot of crosstalk my illustration was very much simplified that means that pathways in the cell can cross interact with other pathways and there's a lot of signaling going on but this is a main pathway and just keep in mind that mTOR will activate cell cycle progression so thanks for watching and see you
