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Gene Review

LDLRAP1  -  low density lipoprotein receptor adaptor...

Homo sapiens

Synonyms: ARH, ARH1, ARH2, Autosomal recessive hypercholesterolemia protein, DKFZp586D0624, ...
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Disease relevance of LDLRAP1


Psychiatry related information on LDLRAP1

  • Food deprivation caused a decrease in sexual receptivity and in the number of detectable PRIR cells in the MPO and medial amygdala but had no effect on the number of detectable PRIR cells in the VMH/VLH, the ARH, or the anteroventral periventricular nucleus [6].
  • The ARH and CM groups had a higher number of subjects with T-scores > or =65, when compared to the migraine group, on the following scales: 1 (hypochondrias), 2 (depression), 8 (schizophrenia) and 0 (social introversion) [7].

High impact information on LDLRAP1

  • Components of this disulfide linked heterodimeric complex, Ig-alpha and Ig-beta, contain an approximately 26 residue sequence motif termed ARH1, also known as TAM, which binds to cytoplasmic effectors, including src-family tyrosine kinases, and contains all structural information needed for signal transduction [8].
  • ARH appears to have a tissue-specific role in LDLR function, as it is required in liver but not in fibroblasts [9].
  • Here we map the ARH locus to an approximately 1-centimorgan interval on chromosome 1p35 and identify six mutations in a gene encoding a putative adaptor protein (ARH) [9].
  • Retroviral expression of normal human ARH1 restores LDL receptor internalization in transformed lymphocytes from an affected individual, as demonstrated by uptake and degradation of (125)I-labeled LDL and confocal microscopy of cells labeled with anti-LDL-receptor Ab [10].
  • Autosomal recessive hypercholesterolaemia in Sardinia, Italy, and mutations in ARH: a clinical and molecular genetic analysis [11].

Chemical compound and disease context of LDLRAP1


Biological context of LDLRAP1

  • To examine the function of ARH, we used pull-down experiments to test for interactions between ARH, the LDLR, and proteins involved in clathrin-mediated endocytosis [15].
  • Recently, the disorder was shown to be caused by mutations in a phosphotyrosine binding domain protein, ARH, which is required for internalization of low density lipoproteins in the liver [1].
  • This review summarizes the findings of new investigations into the pathophysiology and molecular genetics of ARH [1].
  • The only mutation identified in the remaining proband was a SINE VNTR Alu (SVA) retroposon insertion in intron 1, which was associated with no detectable ARH mRNA [2].
  • Direct sequencing of ARH gene demonstrated the presence of a 432insA mutation in homozygosis in the two probands; parents were heterozygotes for the same mutation [16].

Anatomical context of LDLRAP1


Associations of LDLRAP1 with chemical compounds

  • Mutation of a glutamic acid residue in the appendage domain of beta(2)-adaptin that is required for interaction with the adapter protein beta-arrestin markedly reduced binding to ARH [15].
  • Interestingly, ARH is caused by a mutation of cytosine to adenine at this same position [20].
  • In ARH plasma LDL cholestrol (LDL-C) level (14.25+/-2.29mmol/L) was lower than in receptor-negative HoFH (21.38+/-3.56mmol/L) but similar to that found in receptor-defective HoFH (15.52+/-2.39mmol/L) [21].
  • Combination therapy with high-dose statin and ezetimibe seems to be the treatment of choice in ARH and may reduce or eliminate the need for LDL apheresis treatment [22].
  • ARH missense polymorphisms and plasma cholesterol levels [23].

Physical interactions of LDLRAP1

  • Mutations in the NPVY sequence that were previously shown to decrease LDLR internalization abolished in vitro binding to ARH [15].
  • A highly conserved 20-amino acid sequence in the C-terminal region of ARH bound the beta(2)-adaptin subunit of AP-2 [15].

Regulatory relationships of LDLRAP1


Other interactions of LDLRAP1

  • SUMMARY: The available data suggest that ARH functions as an adaptor protein that couples LDLR to the endocytic machinery [1].
  • GST-pulldown experiments indicate that the phosphotyrosine binding domain of ARH interacts with the internalization sequence (NPVY) in the cytoplasmic tail of LDLR, and that conserved motifs in the C-terminal portion of the protein bind to clathrin and to the beta2-adaptin subunit of AP-2 [1].
  • The interaction between ARH and clathrin was mapped to a canonical clathrin box sequence (LLDLE) in ARH and to the N-terminal domain of the clathrin heavy chain [15].
  • However, Dab2 expression is exceptionally low in hepatocytes, likely accounting for the pathological hypercholesterolemia that accompanies ARH loss [25].
  • LDL and GPCRs are internalized by ARH and beta-arrestin, respectively [26].

Analytical, diagnostic and therapeutic context of LDLRAP1

  • Parallel studies performed in vivo with the same recombinant forms of ARH in livers of Arh(-/-) mice confirmed the relevance of the cell culture findings [17].
  • Functional dissection of an AP-2 beta2 appendage-binding sequence within the autosomal recessive hypercholesterolemia protein [27].
  • Sequence analysis of the ARH gene (1p35 locus) revealed that the affected siblings are homozygous for a novel mutation (IVS4+2T>G) affecting the donor splice site in intron 4, whereas both the parents and an unaffected sister are heterozygous for this mutation [28].
  • All of the ARH homozygotes had large tendinous xanthomas, two had exertional angina, and four a positive stress ECG [3].
  • METHODS: We obtained detailed medical histories, did physical examinations, measured concentrations of lipoproteins, and harvested genomic DNA from 28 Sardinians with ARH from 17 unrelated families [11].


  1. Molecular mechanisms of autosomal recessive hypercholesterolemia. Cohen, J.C., Kimmel, M., Polanski, A., Hobbs, H.H. Curr. Opin. Lipidol. (2003) [Pubmed]
  2. Molecular mechanisms of autosomal recessive hypercholesterolemia. Wilund, K.R., Yi, M., Campagna, F., Arca, M., Zuliani, G., Fellin, R., Ho, Y.K., Garcia, J.V., Hobbs, H.H., Cohen, J.C. Hum. Mol. Genet. (2002) [Pubmed]
  3. Clinical and biochemical characterisation of patients with autosomal recessive hypercholesterolemia (ARH). Fellin, R., Zuliani, G., Arca, M., Pintus, P., Pacifico, A., Montali, A., Corsini, A., Maioli, M. Nutrition, metabolism, and cardiovascular diseases : NMCD. (2003) [Pubmed]
  4. Antisense inhibition of macrophage inflammatory protein 1-alpha blocks bone destruction in a model of myeloma bone disease. Choi, S.J., Oba, Y., Gazitt, Y., Alsina, M., Cruz, J., Anderson, J., Roodman, G.D. J. Clin. Invest. (2001) [Pubmed]
  5. Chronic daily headache: identification of factors associated with induction and transformation. Bigal, M.E., Sheftell, F.D., Rapoport, A.M., Tepper, S.J., Lipton, R.B. Headache. (2002) [Pubmed]
  6. Effects of food deprivation on induction of neural progestin receptors by estradiol in Syrian hamsters. Du, Y., Wade, G.N., Blaustein, J.D. Am. J. Physiol. (1996) [Pubmed]
  7. MMPI personality profiles in patients with primary chronic daily headache: a case-control study. Bigal, M.E., Sheftell, F.D., Rapoport, A.M., Tepper, S.J., Weeks, R., Baskin, S.M. Neurol. Sci. (2003) [Pubmed]
  8. Signal transduction by the B cell antigen receptor and its coreceptors. Cambier, J.C., Pleiman, C.M., Clark, M.R. Annu. Rev. Immunol. (1994) [Pubmed]
  9. Autosomal recessive hypercholesterolemia caused by mutations in a putative LDL receptor adaptor protein. Garcia, C.K., Wilund, K., Arca, M., Zuliani, G., Fellin, R., Maioli, M., Calandra, S., Bertolini, S., Cossu, F., Grishin, N., Barnes, R., Cohen, J.C., Hobbs, H.H. Science (2001) [Pubmed]
  10. Restoration of LDL receptor function in cells from patients with autosomal recessive hypercholesterolemia by retroviral expression of ARH1. Eden, E.R., Patel, D.D., Sun, X.M., Burden, J.J., Themis, M., Edwards, M., Lee, P., Neuwirth, C., Naoumova, R.P., Soutar, A.K. J. Clin. Invest. (2002) [Pubmed]
  11. Autosomal recessive hypercholesterolaemia in Sardinia, Italy, and mutations in ARH: a clinical and molecular genetic analysis. Arca, M., Zuliani, G., Wilund, K., Campagna, F., Fellin, R., Bertolini, S., Calandra, S., Ricci, G., Glorioso, N., Maioli, M., Pintus, P., Carru, C., Cossu, F., Cohen, J., Hobbs, H.H. Lancet (2002) [Pubmed]
  12. Whole blood selective LDL-apheresis: a comparison of two different adsorbers. Poli, L., Busnach, G. The International journal of artificial organs. (2006) [Pubmed]
  13. Effects of acute and chronic insulin-induced hypoglycemia on type II glucocorticoid receptor (GR) gene expression in characterized CNS metabolic loci. Kale, A.Y., Vavaiya, K.V., Briski, K.P. Brain Res. Bull. (2006) [Pubmed]
  14. Biochemical and histochemical characteristics of target antigen detected by monoclonal antibody HBCA-12 against a membrane component of human mammary carcinoma cell line. Kovarík, J., Chorváth, B., Duraj, J., Bártek, J., Rejthar, A., Lauerová, L., Babusíková, O. Neoplasma (1984) [Pubmed]
  15. ARH is a modular adaptor protein that interacts with the LDL receptor, clathrin, and AP-2. He, G., Gupta, S., Yi, M., Michaely, P., Hobbs, H.H., Cohen, J.C. J. Biol. Chem. (2002) [Pubmed]
  16. Autosomal recessive hypercholesterolemia in a Sicilian kindred harboring the 432insA mutation of the ARH gene. Barbagallo, C.M., Emmanuele, G., Cefalù, A.B., Fiore, B., Noto, D., Mazzarino, M.C., Pace, A., Brogna, A., Rizzo, M., Corsini, A., Notarbartolo, A., Travali, S., Averna, M.R. Atherosclerosis (2003) [Pubmed]
  17. The modular adaptor protein autosomal recessive hypercholesterolemia (ARH) promotes low density lipoprotein receptor clustering into clathrin-coated pits. Garuti, R., Jones, C., Li, W.P., Michaely, P., Herz, J., Gerard, R.D., Cohen, J.C., Hobbs, H.H. J. Biol. Chem. (2005) [Pubmed]
  18. The adaptor protein ARH escorts megalin to and through endosomes. Nagai, M., Meerloo, T., Takeda, T., Farquhar, M.G. Mol. Biol. Cell (2003) [Pubmed]
  19. The autosomal recessive hypercholesterolemia (ARH) protein interfaces directly with the clathrin-coat machinery. Mishra, S.K., Watkins, S.C., Traub, L.M. Proc. Natl. Acad. Sci. U.S.A. (2002) [Pubmed]
  20. Clinical features and genetic analysis of autosomal recessive hypercholesterolemia. Harada-Shiba, M., Takagi, A., Miyamoto, Y., Tsushima, M., Ikeda, Y., Yokoyama, S., Yamamoto, A. J. Clin. Endocrinol. Metab. (2003) [Pubmed]
  21. Autosomal recessive hypercholesterolemia (ARH) and homozygous familial hypercholesterolemia (FH): A phenotypic comparison. Pisciotta, L., Oliva, C.P., Pes, G.M., Di Scala, L., Bellocchio, A., Fresa, R., Cantafora, A., Arca, M., Calandra, S., Bertolini, S. Atherosclerosis (2006) [Pubmed]
  22. Autosomal recessive hypercholesterolaemia: normalization of plasma LDL cholesterol by ezetimibe in combination with statin treatment. Lind, S., Olsson, A.G., Eriksson, M., Rudling, M., Eggertsen, G., Angelin, B. J. Intern. Med. (2004) [Pubmed]
  23. ARH missense polymorphisms and plasma cholesterol levels. Hubacek, J.A., Hyatt, T. Clin. Chem. Lab. Med. (2004) [Pubmed]
  24. Autosomal recessive hypercholesterolemia protein interacts with and regulates the cell surface level of Alzheimer's amyloid beta precursor protein. Noviello, C., Vito, P., Lopez, P., Abdallah, M., D'Adamio, L. J. Biol. Chem. (2003) [Pubmed]
  25. A Single Common Portal for Clathrin-mediated Endocytosis of Distinct Cargo Governed by Cargo-selective Adaptors. Keyel, P.A., Mishra, S.K., Roth, R., Heuser, J.E., Watkins, S.C., Traub, L.M. Mol. Biol. Cell (2006) [Pubmed]
  26. Molecular switches involving the AP-2 beta2 appendage regulate endocytic cargo selection and clathrin coat assembly. Edeling, M.A., Mishra, S.K., Keyel, P.A., Steinhauser, A.L., Collins, B.M., Roth, R., Heuser, J.E., Owen, D.J., Traub, L.M. Dev. Cell (2006) [Pubmed]
  27. Functional dissection of an AP-2 beta2 appendage-binding sequence within the autosomal recessive hypercholesterolemia protein. Mishra, S.K., Keyel, P.A., Edeling, M.A., Dupin, A.L., Owen, D.J., Traub, L.M. J. Biol. Chem. (2005) [Pubmed]
  28. A novel ARH splice site mutation in a Mexican kindred with autosomal recessive hypercholesterolemia. Canizales-Quinteros, S., Aguilar-Salinas, C.A., Huertas-Vázquez, A., Ordóñez-Sánchez, M.L., Rodríguez-Torres, M., Venturas-Gallegos, J.L., Riba, L., Ramírez-Jimenez, S., Salas-Montiel, R., Medina-Palacios, G., Robles-Osorio, L., Miliar-García, A., Rosales-León, L., Ruiz-Ordaz, B.H., Zentella-Dehesa, A., Ferré-D'Amare, A., Gómez-Pérez, F.J., Tusié-Luna, M.T. Hum. Genet. (2005) [Pubmed]
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