title: The structure of a receptor with two associating transmembrane domains on the cell surface: integrin alphaIIbbeta3.
abstract: Structures of intact receptors with single-pass transmembrane domains are essential to understand how extracellular and cytoplasmic domains regulate association and signaling through transmembrane domains. A chemical and computational method to determine structures of the membrane regions of such receptors on the cell surface is developed here and validated with glycophorin A. An integrin heterodimer structure reveals association over most of the lengths of the alpha and beta transmembrane domains and shows that the principles governing association of hetero and homo transmembrane dimers differ. A turn at the Gly of the juxtamembrane GFFKR motif caps the alpha TM helix and brings the two Phe of GFFKR into the alpha/beta interface. A juxtamembrane Lys residue in beta also has an important role in the interface. The structure shows how transmembrane association/dissociation regulates integrin signaling. A joint ectodomain and membrane structure shows that substantial flexibility between the extracellular and TM domains is compatible with TM signaling.
authors.affiliation: The Immune Disease Institute, Children's Hospital Boston, and Department of Pathology, Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115, USA.
authors.forename: Jieqing
authors.initials: J
authors.lastname: Zhu
authors.forename: Bing-Hao
authors.initials: BH
authors.lastname: Luo
authors.forename: Patrick
authors.initials: P
authors.lastname: Barth
authors.forename: Jack
authors.initials: J
authors.lastname: Schonbrun
authors.forename: David
authors.initials: D
authors.lastname: Baker
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Springer
mesh_terms: D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D019906:Nuclear Magnetic Resonance, Biomolecular; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D015398:Signal Transduction
chemical_list: D019039:Platelet Glycoprotein GPIIb-IIIa Complex