PAG, or Cbp/PAG (Csk binding protein/phospho-protein associated with glycosphingolipid-enriched microdomains) is a transmembrane family that has a negative regulatory role in T-cell activation through being an adapter for C-terminal Src kinase, Csk. This family of proteins is found in eukaryotes.

1: Phosphoprotein associated with glycosphingolipid-enriched microdomains (PAG), a novel ubiquitously expressed transmembrane adaptor protein, binds the protein tyrosine kinase csk and is involved in regulation of T cell activation. Brdicka T, Pavlistova D, Leo A, Bruyns E, Korinek V, Angelisova P, Scherer J, Shevchenko A, Hilgert I, Cerny J, Drbal K, Kuramitsu Y, Kornacker B, Horejsi V, Schraven B; J Exp Med. 2000;191:1591-1604. PMID:10790433

2: Interaction between two adapter proteins, PAG and EBP50: a possible link between membrane rafts and actin cytoskeleton. Brdickova N, Brdicka T, Andera L, Spicka J, Angelisova P, Milgram SL, Horejsi V; FEBS Lett. 2001;507:133-136. PMID:11684085

3: Phosphorylation-dependent regulation of T-cell activation by PAG/Cbp, a lipid raft-associated transmembrane adaptor. Davidson D, Bakinowski M, Thomas ML, Horejsi V, Veillette A; Mol Cell Biol. 2003;23:2017-2028. PMID:12612075

4: Modulation of proximal signaling in normal and transformed B cells by transmembrane adapter Cbp/PAG. Kalland ME, Solheim SA, Skanland SS, Tasken K, Berge T; Exp Cell Res. 2012;318:1611-1619. PMID:22659621