i have a question (maybe stupid). There is an allosteric inhibitor of AKT (MK2206) which shows highly inhibition on p-AKT (T308 and S473). i think this could indicate that the inhibitor works. i do not understand why people also detect phosphorylation of AKT substrate. is it necessary to detect its substrate? Could people having experience with inhibitors help me with this? thank you in advance!
I have no personal experience with AKT or its inhibitors. But in general if you inhibit a kinase and look on the downstream effects, it makes sense to check whether some of the substrates are indeed also affected as an additional control of your experiment. T308/S473 inhibition means there is no phosphorylation of AKT and thus no activation of AKT kinase itself. But what if some other kinase still phosphorylates your substrate? Then your experiment might be compromised. So, it depends on the scope of the work whether it is necessary or not, to check the substrates as well.
I agree with Eugen on multiple substrate effect and their phosphorylation by other targets. to get a complete picture we perform Pamgene multiplex kinome activity arrays (https://pamgene.com/science/) with kinase inhibitors which cover ~350 known kinase substrate and followed by upstream kinase analysis.