Taxonomic distribution of proteins containing LU domains

The tree below includes only several representative species and genera. The complete taxonomic breakdown of all proteins containing LU domains can be accessed here. Click the counts or percentage values to display the corresponding proteins.

Three-dimensional solution structure of the extracellular region of the complement regulatory protein CD59, a new cell-surface protein domain related to snake venom neurotoxins.

Kieffer B, Driscoll PC, Campbell ID, Willis AC, vanderMerwe PA, Davis SJ
Biochemistry. 1994; 33: 4471-82

The cell surface antigen CD59 is an inhibitor of complement-mediated lysis and a member of the Ly6 superfamily (Ly6SF) of cysteine-rich cell-surface molecules whose sequences are related to those of snake venom neurotoxins. The three-dimensional solution structure of a recombinant form of the extracellular region of the molecule (residues 1-70 of the mature protein; sCD59) has been solved by 2D NMR methods. sCD59 is a relatively flat, disk-shaped molecule consisting of a two-standed beta-sheet finger loosely packed against a protein core formed by a three-stranded beta-sheet and a short helix. Structure calculations allowed an unambiguous assignment of the disulfide-bonded cysteine pairs as 3-26, 6-13, 19-39, 45-63, and 64-69. The topology of sCD59 is similar to that of the snake venom neurotoxins and consistent with an evolutionary relationship existing between the Ly6SF and the neurotoxins.

Structure-function relationships in the receptor for urokinase-type plasminogen activator. Comparison to other members of the Ly-6 family and snake venom alpha-neurotoxins.

Ploug M, Ellis V
FEBS Lett. 1994; 349: 163-8

Plasminogen activation is regulated by the interaction between urokinase-type plasminogen activator (uPA) and its specific glycolipid-anchored cell surface receptor (uPAR). uPAR is composed of three homologous domains and is the only multi-domain member of the Ly-6 family of glycolipid-anchored membrane proteins. Recent evidence has highlighted similarities between the individual domains of uPAR and the large family of secreted, single domain snake venom alpha-neurotoxins, suggesting that uPAR may adopt the same gross folding pattern as these structurally well characterized proteins. Structural aspects of the binding between alpha-neurotoxins and the acetylcholine receptor may have a major influence on future studies of the interaction between uPA and uPAR.

The ligand-binding domain of the cell surface receptor for urokinase-type plasminogen activator.

Behrendt N, Ploug M, Patthy L, Houen G, Blasi F, Dano K
J Biol Chem. 1991; 266: 7842-7

The purified urokinase plasminogen activator receptor (u-PAR) was cleaved into two fragments by mild chymotrypsin treatment. The smaller fragment (apparent Mr 16,000) possessed the ligand-binding capability, as shown by chemical cross-linking analysis. This fragment constituted the NH2-terminal part of the intact receptor, probably including the whole sequence 1-87, and contained N-linked carbohydrate. After detergent phase separation in the Triton X-114 system, the fragment was present in the water phase where its binding activity could be demonstrated in the absence of the rest of the protein. An analysis of internal homology in the amino acid sequence of u-PAR revealed the presence of three repeats of approximately 90 residues each. The ligand-binding fragment corresponds to the first repeat, supporting that this unit is a structurally autonomous domain. Domains homologous with the internal repeats of u-PAR constitute the extracellular part of Ly-6 antigens and of the squid glycoprotein Sgp-2. Like u-PAR, these proteins are attached to the membrane by a glycosyl-phosphatidylinositol anchor. The hydrophilic, ligand-binding u-PAR domain identified in the present study has potential applications in interfering with cell-surface plasmin-mediated proteolysis.

Protein structure and membrane anchorage of the cellular receptor for urokinase-type plasminogen activator.

Ploug M, Behrendt N, Lober D, Dano K
Semin Thromb Hemost. 1991; 17: 183-93