Biology:CD59 antigen

From HandWiki
u-PAR/Ly-6 domain
Cd59b.png
Identifiers
SymbolUPAR_LY6
PfamPF00021
InterProIPR001526
PROSITEPDOC00756
SCOP21erg / SCOPe / SUPFAM
CDDcd00117

CD59 antigen (also called 1F-5Ag, H19, HRF20, MACIF, MIRL, P-18 or protectin) inhibits formation of membrane attack complex (MAC), thus protecting cells from complement-mediated lysis. It has a signaling role, as a GPI anchored molecule, in T cell activation and appears to have some role in cell adhesion through CD2 (controversial). CD59 associates with C9, inhibiting incorporation into C5b-8 preventing terminal steps in polymerization of the (MAC) in plasma membranes. Genetic defects in GPI-anchor attachment that cause a reduction or loss of both CD59 and CD55 on erythrocytes produce the symptoms of the disease paroxysmal nocturnal hemoglobinuria (PNH).

A variety of GPI-linked cell-surface glycoproteins are composed of one or more copies of a conserved domain of about 100 amino-acid residues.[2][3] Among these proteins, U-PAR contains three tandem copies of the domain, while all the others are made up of a single domain.

As shown in the following schematic, this conserved domain contains 10 cysteine residues involved in five disulfide bonds - in U-PAR, the first copy of the domain lacks the fourth disulfide bond.

    +------+     +------------------------+                    +---+
    |      |     |                        |                    |   |
 |                     |                       |              |
 +---------------------+                       +--------------+

'C': conserved cysteine involved in a disulfide bond.

CD molecules are leucocyte antigens on cell surfaces. CD antigens nomenclature is updated at Protein Reviews On The Web (http://mpr.nci.nih.gov/prow/).

Subfamilies

Human proteins containing this domain

ARS; CD177; CD59; LY6D; LY6E; LY6H; LYNX1; LYPD2; LYPD3; LYPD4; LYPD5; LYPD6; PLAUR; PSCA; SLURP2; SLURP1; SPACA4; TEX101;

References

  1. PDB: 2J8B​; "High-resolution structures of bacterially expressed soluble human CD59". Acta Crystallographica Section F 63 (Pt 8): 648–52. August 2007. doi:10.1107/S1744309107033477. PMID 17671359. 
  2. "The ligand-binding domain of the cell surface receptor for urokinase-type plasminogen activator". J. Biol. Chem. 266 (12): 7842–7847. 1991. PMID 1850423. 
  3. "Localization of the disulfide bonds in the NH2-terminal domain of the cellular receptor for human urokinase-type plasminogen activator. A domain structure belonging to a novel superfamily of glycolipid-anchored membrane proteins". J. Biol. Chem. 268 (23): 17539–17546. 1993. PMID 8394346. 
This article incorporates text from the public domain Pfam and InterPro: IPR001526