6eho
From Proteopedia
Dimer of the Sortilin Vps10p domain at low pH
Structural highlights
DiseaseSORT_HUMAN Note=A common polymorphism located in a non-coding region between CELSR2 and PSRC1 alters a CEBP transcription factor binding site and is responsible for changes in hepatic expression of SORT1. Altered SORT1 expression in liver affects low density lipoprotein cholesterol levels in plasma and is associated with susceptibility to myocardial infarction. FunctionSORT_HUMAN Functions as a sorting receptor in the Golgi compartment and as a clearance receptor on the cell surface. Required for protein transport from the Golgi apparatus to the lysosomes by a pathway that is independent of the mannose-6-phosphate receptor (M6PR). Also required for protein transport from the Golgi apparatus to the endosomes. Promotes neuronal apoptosis by mediating endocytosis of the proapoptotic precursor forms of BDNF (proBDNF) and NGFB (proNGFB). Also acts as a receptor for neurotensin. May promote mineralization of the extracellular matrix during osteogenic differentiation by scavenging extracellular LPL. Probably required in adipocytes for the formation of specialized storage vesicles containing the glucose transporter SLC2A4/GLUT4 (GLUT4 storage vesicles, or GSVs). These vesicles provide a stable pool of SLC2A4 and confer increased responsiveness to insulin. May also mediate transport from the endoplasmic reticulum to the Golgi.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] Publication Abstract from PubMedSortilin is a neuronal receptor involved in transmembrane signaling, endocytosis, and intracellular sorting of proteins. It cycles through a number of cellular compartments where it encounters various acidic conditions. The crystal structure of the sortilin ectodomain has previously been determined at neutral pH. Here, we present the 3.5-A resolution crystal structure of sortilin at pH 5.5, which represents an environment similar to that of late endosomes, where ligands are released. The structure reveals an overall distortion of the 10-bladed beta-propeller domain. This distortion and specific conformational changes, caused by protonation of a number of histidine residues, render the currently known binding sites unavailable for ligand binding. Access to the binding sites is furthermore blocked by a reversible and pH-dependent formation of tight sortilin dimers, also confirmed by electron microscopy, size-exclusion chromatography, and mutational studies. This study reveals how sortilin binding sites are disrupted and explains pH-dependent ligand affinity. Acidic Environment Induces Dimerization and Ligand Binding Site Collapse in the Vps10p Domain of Sortilin.,Januliene D, Andersen JL, Nielsen JA, Quistgaard EM, Hansen M, Strandbygaard D, Moeller A, Petersen CM, Madsen P, Thirup SS Structure. 2017 Oct 12. pii: S0969-2126(17)30328-3. doi:, 10.1016/j.str.2017.09.015. PMID:29107483[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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