B7-1 homodimer/ B7-2 CTLA-4:PP2A PP2A:CTLA4:B7-1/B7-2 CTLA-4 binds B7-1/B7-2 Authored: Garapati, P V, 2008-12-16 11:12:19 CTLA4 binds with high affinity to the ligands B71 and B72. The interaction of B7 molecules with CTLA4 provides inhibitory signals required for downregulation of the TCR response. The interaction is mediated by the CDR3 analogous loop of CTLA4, composed of an MYPPY motif, with a concave surface on the B7 formed predominately by the G, F, C, C' and C" strands. Its also been demonstrated that B7 binding is not totally essential for CTLA-4 activity. Edited: Garapati, P V, 2008-12-16 11:12:19 Pubmed10799894 Pubmed11976720 Pubmed15142525 Reactome Database ID Release 43388809 Reactome, http://www.reactome.org ReactomeREACT_19129 Reviewed: Bluestone, JA, Esensten, J, 2009-06-01 18:47:33