Meta-Biol

• Pathways

MHC II:Ii complexes are internalized in to the endocytic clathrin coated-pit. Dynamin, the GTPase involved in the scission of clathrin-coated vesicles from plasma membrane is observed to be involved in the effective endocytosis of MHC II:Ii complexes. Wang et al, demonstrated that overexpression of a dominant-negative mutant of the GTPase dynamin resulted in the cell surface accumulation of MHC II:Ii complex, supporting that endocytosis is required for delivery to antigen processing compartments (Wang et al, 1997). However, another study using the same dynamin mutant generated opposite conclusions (Davidson, 1999). This discrepancy may be caused by differences in experimental set-up and in the levels of expression of the dynamin mutant and MHC II chains (Dugast et al, 2005).