Question

                a. What are the steps/characteristics of lysosome centered protein degradation? Discuss any specificities and give an example of at least one protein which is cleared via the lysosomal degradation.

  

                b. What are the steps in the proteasome centered protein degradation via ubiquitination? Include the labeling with ubiquitin and the steps in proteasome and post proteasome processing. Discuss any specificities and give an example of at least one protein which is degraded via ubiquitination and the proteasome.

               

    iv) Protein degradation may also be a way of regulating enzyme activities. What is an example of regulation of a key enzyme of a pathway where a product or effector regulates enzyme activity by increasing or decreasing the rate of degradation of the enzyme protein?  

Answer 1

A. Lysosomal degradations takes place in two steps which include uptake of proteins into lysosomes include organelles, secretary vesicles and cytoplasm. Wherein lysosomes will uptake certain cytosolic proteins in response to cellular starvation. The proteins which gets degraded by lysosomes will have amino acid sequences lys, phe, glu, arg and gln so that it will easily target lysosomes.

B. Through proteosome cantered protein degradation, the first step will be activation of ubiquitin by enzyme E 1 and then activated ubiquitin will gets transferred to ubiquitin conjugated enzymes which is E2 and in most of the cases ubiquitin is transferred to ubiquitin ligand and then in the next step it is transferred to target protein.