T-cell surface glycoprotein CD8 beta chain (CD antigen CD8b)
1_MRPRL 6_ WLLLA 11_ AQLTV 16_ LHGNS 21_ VLQQT 26_ PAYIK 31_ VQTNK 36_ MVMLS 41_ CEAKI 46_ SLSNM 51_ RIYWL 56_ RQRQA 61_ PSSDS 66_ HHEFL 71_ ALWDS 76_ AKGTI 81_ HGEEV 86_ EQEKI 91_ AVFRD 96_ ASRFI 101_ LNLTS 106_ VKPED 111_ SGIYF 116_ CMIVG 121_ SPELT 126_ FGKGT 131_ QLSVV 136_ DFLPT 141_ TAQPT 146_ KKSTL 151_ KKRVC 156_ RLPRP 161_ ETQKG 166_ PLCSP 171_ ITLGL 176_ LVAGV 181_ LVLLV 186_ SLGVA 191_ IHLCC 196_ RRRRA 201_RLRFM
1: Integral membrane glycoprotein that plays an essential role in the immune response and serves multiple functions in responses against both external and internal offenses. In T-cells, functions primarily as a coreceptor for MHC class I molecule:peptide complex. The antigens presented by class I peptides are derived from cytosolic proteins while class II derived from extracellular proteins. Interacts simultaneously with the T-cell receptor (TCR) and the MHC class I proteins presented by antigen presenting cells (APCs). In turn, recruits the Src kinase LCK to the vicinity of the TCR-CD3 complex. A palmitoylation site in the cytoplasmic tail of CD8B chain contributes to partitioning of CD8 into the plasma membrane lipid rafts where signaling proteins are enriched. Once LCK recruited, it initiates different intracellular signaling pathways by phosphorylating various substrates ultimately leading to lymphokine production, motility, adhesion and activation of cytotoxic T-lymphocytes (CTLs). Additionally, plays a critical role in thymic selection of CD8+ T-cells