title: Transmembrane Complexes of DAP12 Crystallized in Lipid Membranes Provide Insights into Control of Oligomerization in Immunoreceptor Assembly.
abstract: The membrane-spanning α helices of single-pass receptors play crucial roles in stabilizing oligomeric structures and transducing biochemical signals across the membrane. Probing intermolecular transmembrane interactions in single-pass receptors presents unique challenges, reflected in a gross underrepresentation of their membrane-embedded domains in structural databases. Here, we present two high-resolution structures of transmembrane assemblies from a eukaryotic single-pass protein crystallized in a lipidic membrane environment. Trimeric and tetrameric structures of the immunoreceptor signaling module DAP12, determined to 1.77-Å and 2.14-Å resolution, respectively, are organized by the same polar surfaces that govern intramembrane assembly with client receptors. We demonstrate that, in addition to the well-studied dimeric form, these trimeric and tetrameric structures are made in cells, and their formation is competitive with receptor association in the ER. The polar transmembrane sequences therefore act as primary determinants of oligomerization specificity through interplay between charge shielding and sequestration of polar surfaces within helix interfaces.
authors.affiliation: Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC 3052, Australia.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Knoblich
authors.affiliation: Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas, Lawrence, KS 66047, USA.
authors.forename: Soohyung
authors.initials: S
authors.lastname: Park
authors.affiliation: Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia.
authors.forename: Mariam
authors.initials: M
authors.lastname: Lutfi
authors.affiliation: Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, VIC 3010, Australia; Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, VIC 3010, Australia; CSIRO Manufacturing Flagship, Clayton, VIC 3169, Australia.
authors.forename: Leonie
authors.initials: L
authors.lastname: van 't Hag
authors.affiliation: School of Applied Sciences, College of Science, Engineering and Health, RMIT University, Melbourne, VIC 3001, Australia.
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Conn
authors.affiliation: CSIRO Manufacturing Flagship, Parkville, VIC 3052, Australia.
authors.forename: Shane A
authors.initials: SA
authors.lastname: Seabrook
authors.affiliation: CSIRO Manufacturing Flagship, Parkville, VIC 3052, Australia.
authors.forename: Janet
authors.initials: J
authors.lastname: Newman
authors.affiliation: Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC 3052, Australia.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Czabotar
authors.affiliation: Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas, Lawrence, KS 66047, USA.
authors.forename: Wonpil
authors.initials: W
authors.lastname: Im
authors.affiliation: Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC 3052, Australia. Electronic address: call@wehi.edu.au.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Call
authors.affiliation: Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, VIC 3052, Australia. Electronic address: call@wehi.edu.au.
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Call
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D000595:Amino Acid Sequence; D018360:Crystallography, X-Ray; D006801:Humans; D008563:Membrane Lipids / Q000737:chemistry* / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D015398:Signal Transduction
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D008563:Membrane Lipids; D008565:Membrane Proteins; C110546:TYROBP protein, human