High impact information on LDLR

• Molecular characterization of the VLDL/VTGR revealed that it is a member of the LDLR gene superfamily, and harbours eight complement-type, cysteine-rich ligand binding repeats at the N-terminus [1].
• Chicken oocyte growth is mediated by an eight ligand binding repeat member of the LDL receptor family [1].
• Furthermore, the chicken vitellogenin receptor, which also binds apolipoproteins receptor (LDLR) superfamily [Bujo, H., Hermann, M., Kaderli, M. O., Jacobsen, L., Sugawara, S., Nimpf, J., Yamamoto, T. & Schneider, W. J. (1994) EMBO J. 13, 5165-5175] [2].
• Chicken RAP in crude extracts of the stable expressor COS cells is able to bind to LDLR relatives in ligand blots without requirement for prior purification of the ligand [3].
• The normal cellular function of the Tva receptor is unknown; however, the extracellular domain contains a 40-amino-acid, cysteine-rich region that is homologous to the ligand binding region of the low-density lipoprotein receptor (LDLR) proteins [4].

Biological context of LDLR

• Line C tva(r) contains a single base pair substitution, resulting in a cysteine-to-tryptophan change in the LDLR-like region of Tva [4].
• Systemic cholesterol homeostasis in the chicken is maintained by expressing a different apoprotein B-specific receptor in somatic cells, which in terms of its function is very similar to the mammalian LDL receptor [5].
• Whether this difference between pigeon and mammalian cells with respect to LDL receptor activity is the result of differences in the molecular structure of the pigeon LDL receptor remains to be determined [6].

Associations of LDLR with chemical compounds

• This is also compatible with the fact that estrogen administration increased hepatic LDLR expression in roosters despite dramatically stimulated VLDL production [7].
• Molecular characterization of the first avian LDL receptor: role in sterol metabolism of ovarian follicular cells [7].

References