title: The LDL receptor clustering motif interacts with the clathrin terminal domain in a reverse turn conformation.
abstract: Previously the hexapeptide motif FXNPXY807 in the cytoplasmic tail of the LDL receptor was shown to be essential for clustering in clathrin-coated pits. We used nuclear magnetic resonance line-broadening and transferred nuclear Overhauser effect measurements to identify the molecule in the clathrin lattice that interacts with this hexapeptide, and determined the structure of the bound motif. The wild-type peptide bound in a single conformation with a reverse turn at residues NPVY. Tyr807Ser, a peptide that harbors a mutation that disrupts receptor clustering, displayed markedly reduced interactions. Clustering motif peptides interacted with clathrin cages assembled in the presence or absence of AP2, with recombinant clathrin terminal domains, but not with clathrin hubs. The identification of terminal domains as the primary site of interaction for FXNPXY807 suggests that adaptor molecules are not required for receptor-mediated endocytosis of LDL, and that at least two different tyrosine-based internalization motifs exist for clustering receptors in coated pits.
authors.affiliation: Department of Cell Biology and Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas, 75235, USA.
authors.forename: R G
authors.initials: RG
authors.lastname: Kibbey
authors.forename: J
authors.initials: J
authors.lastname: Rizo
authors.forename: L M
authors.initials: LM
authors.lastname: Gierasch
authors.forename: R G
authors.initials: RG
authors.lastname: Anderson
mesh_terms: D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002966:Clathrin / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D011973:Receptors, LDL / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D033962:Adaptor Protein Complex 2; D033965:Adaptor Protein Complex alpha Subunits; D033942:Adaptor Proteins, Vesicular Transport; D002966:Clathrin; D008565:Membrane Proteins; D011973:Receptors, LDL; D011993:Recombinant Fusion Proteins