T-cell-specific surface glycoprotein CD28 (TP44) (CD antigen CD28)
1_MLRLL 6_ LALNL 11_ FPSIQ 16_ VTGNK 21_ ILVKQ 26_ SPMLV 31_ AYDNA 36_ VNLSC 41_ KYSYN 46_ LFSRE 51_ FRASL 56_ HKGLD 61_ SAVEV 66_ CVVYG 71_ NYSQQ 76_ LQVYS 81_ KTGFN 86_ CDGKL 91_ GNESV 96_ TFYLQ 101_ NLYVN 106_ QTDIY 111_ FCKIE 116_ VMYPP 121_ PYLDN 126_ EKSNG 131_ TIIHV 136_ KGKHL 141_ CPSPL 146_ FPGPS 151_ KPFWV 156_ LVVVG 161_ GVLAC 166_ YSLLV 171_ TVAFI 176_ IFWVR 181_ SKRSR 186_ LLHSD 191_ YMNMT 196_ PRRPG 201_ PTRKH 206_ YQPYA 211_PPRDF
1: Receptor that plays a role in T-cell activation, proliferation, survival and the maintenance of immune homeostasis (PubMed:1650475, PubMed:7568038). Functions not only as an amplifier of TCR signals but delivers unique signals that control intracellular biochemical events that alter the gene expression program of T-cells (PubMed:24665965). Stimulation upon engagement of its cognate ligands CD80 or CD86 increases proliferation and expression of various cytokines in particular IL2 production in both CD4(+) and CD8(+) T-cell subsets (PubMed:1650475, PubMed:35397202). Mechanistically, ligation induces recruitment of protein kinase C-theta/PRKCQ and GRB2 leading to NF-kappa-B activation via both PI3K/Akt-dependent and -independent pathways (PubMed:21964608, PubMed:24665965, PubMed:7568038). In conjunction with TCR/CD3 ligation and CD40L costimulation, enhances the production of IL4 and IL10 in T-cells (PubMed:8617933)
2: Enhances CD40L-mediated activation of NF-kappa-B and kinases MAPK8 and PAK2 in T-cells (PubMed:15067037)