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Protein Domain : IPR023415

Name  Low-density lipoprotein (LDL) receptor class A, conserved site Short Name  LDLR_class-A_CS
Type  Conserved_site Description  Low-density lipoprotein (LDL) receptors are the major cholesterol-carrying lipoproteins of plasma. Seven successive cysteine-rich repeats of about 40 amino acids are present in the N-terminal of this multidomain membrane protein []. Similar domains have been found (see references in []) in other extracellular and membrane proteins which are listed below: Vertebrate very low density lipoprotein (VLDL) receptor, which binds and transports VLDL. Its extracellular domain is composed of 8 LDLRA domains, 3 EGF-like domains and 6 LDL-receptor class B domains (LDLRB). Vertebrate low-density lipoprotein receptor-related protein 1 (LRP1) (reviewed in []), which may act as a receptor for the endocytosis of extracellular ligands. LRP1 contains 31 LDLRA domains and 22 EGF-like domains. Vertebrate low-density lipoprotein receptor-related protein 2 (LRP2) (also known as gp330 or megalin). LRP2 contains 36 LDLRA domains and 17 EGF-like domains. A LRP-homologue from Caenorhabditis elegans, which contains 35 LDLRA domains and 17 EGF-like domains. Drosophila putative vitellogenin receptor, with 13 copies of LDLRA domains and 17 EGF-like repeats. Complement factor I, which is responsible for cleaving the alpha-chains of C4b and C3b. It consists of a FIMAC domain (Factor I/MAC proteins C6/C7), a scavenger receptor-like domain, 2 copies of LDLRA and a C-terminal serine protease domain. Complement components C6, C7, C8 and C9. They contain each one LDLRA domain. Perlecan, a large multidomain basement membrane heparan sulphate proteoglycan composed of 4 LDLRA domains, 3 LamB domains, 12 laminin EGF- like domains, 14-21 IG-like domains, 3 LamG domains, and 4 EGF-like domains. A similar but shorter proteoglycan (UNC52) is found in Caenorhabditis elegans which has 3 repeats of LDLRA. Invertebrate giant extracellular hemoglobin linker chains, which allow heme-containing chains to construct giant hemoglobin (1 LDLRA domain). G-protein coupled receptor Grl101 of the snail Lymnaea stagnalis, which might directly transduce signals carried by large extracellular proteins. Vertebrate enterokinase (EC, a type II membrane protein of the intestinal brush border, which activates trypsinogen. It consists at least of a catalytic light chain and a multidomain heavy chain which has 2 LDLRA, a MAM domain (see ), a SRCR domain (see ) and a CUB domain (see ).Human autosomal dominant polycystic kidney disease protein 1 (PKD1), which is involved in adhesive protein-protein and protein-carbohydrate interactions. The potential calcium-binding site of its single LDLRA domain is missing. Vertebrate integral membrane protein DGCR2/IDD, a potential adhesion receptor with 1 LDLRA domain, a C-type lectin and a VWFC domain (see ).Drosophila serine protease nudel (EC 3.4.21.-), which is involved in the induction of dorsoventral polarity of the embryo. It has 11 LDLRA domains, 3 of which miss the first disulphide bond (C1-C3). Avian subgroup A rous sarcoma virus receptor (1 copy of LDLRA). Bovine Sco-spondin, which is secreted by the subcommissural organ in embryos and is involved in the modulation of neuronal aggregation. It contains at least 2 EGF-like domains and 3 LDLRA domains. The LDL-receptor class A domain contains 6 disulphide-bound cysteines []and a highly conserved cluster of negatively charged amino acids, of which many are clustered on one face of the module []. A schematic representation of this domain is shown here: +---------------------+ +--------------------------------+| | | |-CxxxxxxxxxxxxCxxxxxxxxCxxxxxxxxCxxxxxxxxxxCxxxxxxxxxxxxxxxxxxxxxC-| *******************************************| |+----------------------------+'C': conserved cysteine involved in a disulphide bond.'x': any residue.'*': position of the pattern.In LDL-receptors the class A domains form the binding site for LDL []and calcium. The acidic residues between the fourth and sixth cysteines are important for high-affinity binding of positively charged sequences in LDLR's ligands []. The repeat has been shown []to consist of a beta-hairpin structure followed by a series of beta-turns. The binding of calcium seems to induce no significant conformational change.

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0 Child Features

0 Contains

1 Cross References

Source . Name

Subject . Primary Identifier
PS01209 PROSITE IPR023415

2 Data Sets

Name URL
TrEMBL data set
InterPro data set  

0 Found In

0 GO Annotation

0 Ontology Annotations

0 Parent Features

343 Proteins

DB identifier Primary Accession
Organism . Name
FBpp0288558 Q9VM55 Drosophila melanogaster
FBpp0291372 E1JHA6 Drosophila melanogaster
FBpp0076693 P98159 Drosophila melanogaster
FBpp0073715 P98163 Drosophila melanogaster
FBpp0112077 Q5BIG2 Drosophila melanogaster
FBpp0076399 Q8IQA8 Drosophila melanogaster
FBpp0076398 Q9VSI3 Drosophila melanogaster
FBpp0076397 Q8IQA9 Drosophila melanogaster
FBpp0079096 Q9VLZ6 Drosophila melanogaster
FBpp0086821 A1Z9D7 Drosophila melanogaster
FBpp0076333 Q7KUB3 Drosophila melanogaster
FBpp0076252 Q8IQB8 Drosophila melanogaster
FBpp0071118 Q9W3H0 Drosophila melanogaster
FBpp0073931 Q9VXM0 Drosophila melanogaster
FBpp0084302 Q86B77 Drosophila melanogaster
FBpp0086768 Q4V6B0 Drosophila melanogaster
FBpp0083176 Q7JRL9 Drosophila melanogaster
FBpp0087128 Q95NU8 Drosophila melanogaster
FBpp0084273 Q9VBP0 Drosophila melanogaster
FBpp0077926 Q9VPA1 Drosophila melanogaster
FBpp0079703 Q9Y110 Drosophila melanogaster
FBpp0289593 Q0IGY0 Drosophila melanogaster
FBpp0309270 B5X533 Drosophila melanogaster
FBpp0112390 A8JRD1 Drosophila melanogaster
FBpp0290685 A8JRD0 Drosophila melanogaster
FBpp0290682 Q9VBN0 Drosophila melanogaster
FBpp0290684 Q6NP71 Drosophila melanogaster
FBpp0290686 E1JIX9 Drosophila melanogaster
FBpp0290681 Q9VBN1 Drosophila melanogaster
FBpp0303609 R9PY60 Drosophila melanogaster