MHC2-interact (PF09307) is the interaction domain of CLIP and MHC2. Members of this family are found in Class II Invariant Chain Related Peptides (CLIP). They are required for binding to the Class II Major Histocompatibility Complex (MHC) in the MHC Class II processing pathway. MHCassoc_trimer (PF08831) is an invariant chain trimerization domain related to class II MHC. The folding and positioning of MHC class II heterodimers require class II-related consistent chain peptides. This domain participates in the trimerization of the ectoderm and interferes with DM/Class II binding. The trimeric protein forms a cylindrical shape, which is considered necessary for the interaction between the invariant and class II molecules.