title: How calcium makes endocytic receptors attractive.
abstract: Nutrients, biological waste-products, toxins, pathogens, and other ligands for endocytosis are typically captured by multidomain receptors with multiligand specificity. Upon internalization, the receptor-ligand complex segregates, followed by lysosomal degradation of the ligand and recycling of the receptor. Endosomal acidification and calcium efflux lead to the essential ligand-receptor affinity switch and separation. Recent data, including crystal structures of receptor-ligand complexes, now reveal how calcium, in different types of domain scaffolds, functions in a common way as a removable 'lynchpin' that stabilizes favorable positioning of ligand-attractive receptor residues. In addition to explaining how calcium depletion can cause ligand-receptor dissociation, the new data add further insight into how acidification contributes to dissociation through structural changes that affect the receptor calcium sites.
authors.affiliation: Department of Biomedicine, Aarhus University, Ole Worms Allé 3, 8000 Aarhus C, Denmark.
authors.forename: Christian B F
authors.initials: CB
authors.lastname: Andersen
authors.affiliation: Department of Biomedicine, Aarhus University, Ole Worms Allé 3, 8000 Aarhus C, Denmark. Electronic address: skm@biokemi.au.dk.
authors.forename: Søren K
authors.initials: SK
authors.lastname: Moestrup
mesh_terms: D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling; D004705:Endocytosis / Q000235:genetics*; D011992:Endosomes / Q000378:metabolism*; D005057:Eukaryotic Cells / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D008958:Models, Molecular; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D008024:Ligands; D011956:Receptors, Cell Surface; D002118:Calcium
keywords: C-type lectin; CUB; EGF-like; LDL receptor; scavenger receptor