Essay About C-Dependant Caspase Activation And Proposed Mechanism Of Action Of Smac

Smc – a Mitochondrial Protein That Promotes C-Dependant Caspase Activation by Eliminating Iap Inhibition
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Introduction to biochemical methodologiesPaper1- Smac, a Mitochondrial protein that promotes c-Dependant Caspase Activation by eliminating IAP inhibitionDescribe what triggered the investigations of this paper. Scientists discovered that certain types of cells are not responsive to microinjected cytochrome c. They performed a test on healthy neurons and observed that they do not respond to microinjected cytochrome c unless they have been subjected to NGF (nerve growth factor) withdrawal for a certain period of time which gave these neurons the status “competent to die”. This suggests additional caspase-activating protein factors that are potentially regulated by the Bcl-2 family proteins that also regulate cytochrome-C Briefly discuss the proposed mechanism of action of Smac and the evidence provided for this mechanism in the paper.They found that Smac stimulates caspase activation but they have 2 theories as to how this occurs:1. Eliminating an inhibitor(s) in the S-1002. Or directly acting on Apaf-1, cytochrome C and procaspase-9 to enhance the activation efficiency of caspases. Smac was coupled with nickel andwas added to S-100, this was then centrifuged and tested for caspase-3 activation. Result: activation was observed to be higher in the S-100 treated with Smac and nickel compared to that of the S-100 treated with just nickel. Adding free Smac to extracts with uncoupled nickel were responsive whereas extracts which had already been exposed to Smac did not increase in caspase-3 activityThey tested whether the inhibitors that came out from the aforementioned process was IAPs, using Western Blot Analysis. Adding Smac to the extract that does not have inhibitors anymore, didn’t increase caspase-3 activity, which therefore suggests that Smac does not activate caspase-3 but rather inhibits the IAPs, therefore allowing caspase-3 to act.