Mouse invariant chain γ exhibits structural homology to both polymorphic subunits of the α,β-core complex of I-Ak antigens

AbstractThe 3 major constituents of the I-Ak subregion-associated complex α, β and γ were obtained from splenocytes in homogeneous form by differential isolation methods. α, β and γ were compared on the primary structural level by enzymatic fragmentation procedures and tryptic peptide map analysis of radiolabeled proteins. The data indicate that the invariant chain γ exhibits extensive structural homology to the polymorphic β-light and the α-heavy chain. Thus, although not being encoded within the MHC γ appears to belong structurally to the MHC-encoded class II proteins