2i4k
From Proteopedia
Solution Structure of the PX domain of Sorting Nexin 1
Structural highlights
Function[SNX1_HUMAN] May be involved in several stages of intracellular trafficking. Plays a role in targeting ligand-activated EGFR to the lysosomes for degradation after endocytosis from the cell surface and release from the Golgi. Component of the retromer complex, a complex required to retrieve lysosomal enzyme receptors (IGF2R and M6PR) from endosomes to the trans-Golgi network. Interacts with membranes containing phosphatidylinositol 3-phosphate (PtdIns(3P)) or phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2).[1] [2] [3] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe sorting nexin (SNX) family of proteins is characterized by sequence-related phox homology (PX) domains. A minority of PX domains bind with high affinity to phosphatidylinositol 3-phosphate [PI(3)P], whereas the majority of PX domains exhibit low affinity that is insufficient to target them to vesicles. SNX1 is located on endosomes, but its low affinity PX domain fails to localize in vivo. The NMR structure of the PX domain of SNX1 reveals an overall fold that is similar to high-affinity PX domains. However, the phosphatidylinositol (PI) binding pocket of the SNX1 PX domain is incomplete; regions of the pocket that are well defined in high-affinity PX domains are highly mobile in SNX1. Some of this mobility is lost upon binding PI(3)P. The C-terminal domain of SNX1 is a long helical dimer that localizes to vesicles but not to the early endosome antigen-1-containing vesicles where endogenous SNX1 resides. Thus, the obligate dimerization of SNX1 that is driven by the C-terminal domain creates a high-affinity PI binding species that properly targets the holo protein to endosomes. Determinants of the endosomal localization of sorting nexin 1.,Zhong Q, Watson MJ, Lazar CS, Hounslow AM, Waltho JP, Gill GN Mol Biol Cell. 2005 Apr;16(4):2049-57. Epub 2005 Jan 26. PMID:15673616[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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