Control of MHC II antigen presentation by ubiquitination.

MHC II antigen presentation is a critical pathway involved in the activation of the adaptive immune system. Tight regulatory controls are necessary to ensure appropriate MHC II antigen presentation. One mechanism for regulating this pathway is ubiquitination. Ubiquitination has been shown to play a critical role in fine-tuning the regulation of MHC II antigen presentation, with significant roles in antigen receptor internalisation and turnover of MHC II at the cell surface. The importance of ubiquitination is highlighted by bacterial pathogens that hijack the pathway to evade immune recognition. Understanding how ubiquitin E2 and E3 ligases contribute to controlling MHC II antigen presentation will shed light on the critical regulatory controls of this important pathway of immunity.