The Role of Ubiquitination and Sumoylation in Diabetic Nephropathy

Figure 2

The process of activation of NF-κB. In the resting state, NF-κB combined with suppressed protein IκB to compose a heterotrimer in the cytoplasm by an inactive form that would stop NF-κB from entering the nucleus. When cell was stimulated by extracellular stress, the subunit of I kappa B kinase (IκB kinase, IKK), IKKβ would be activated first, and then the IκB would be phosphorylated, and the lysine residues in this domain cause ubiquitination. After the ubiquitination of IκB, it would be degraded by the 26S proteasome of UPP. At last, the heterotrimer dissociate, so that the heterodimers of p50-p65 exhibit the activity of NF-κB and enter in the nucleus to be involved in gene transcription and protein synthesis.