title: Membrane insertion and topology of the translocon-associated protein (TRAP) gamma subunit.
abstract: Translocon-associated protein (TRAP) complex is intimately associated with the ER translocon for the insertion or translocation of newly synthesised proteins in eukaryotic cells. The TRAP complex is comprised of three single-spanning and one multiple-spanning subunits. We have investigated the membrane insertion and topology of the multiple-spanning TRAP-γ subunit by glycosylation mapping and green fluorescent protein fusions both in vitro and in cell cultures. Results demonstrate that TRAP-γ has four transmembrane (TM) segments, an Nt/Ct cytosolic orientation and that the less hydrophobic TM segment inserts efficiently into the membrane only in the cellular context of full-length protein.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Bañó-Polo
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Martínez-Garay
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain.
authors.forename: Brayan
authors.initials: B
authors.lastname: Grau
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez-Gil
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BioTecMed), Universitat de València, E-46 100 Burjassot, Spain. Electronic address: Ismael.Mingarro@uv.es.
authors.forename: Ismael
authors.initials: I
authors.lastname: Mingarro
mesh_terms: D002135:Calcium-Binding Proteins / Q000737:chemistry*; D004721:Endoplasmic Reticulum / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008562:Membrane Glycoproteins / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D021122:Protein Subunits; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry*; D018000:Receptors, Peptide / Q000737:chemistry*
chemical_list: D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D021122:Protein Subunits; D018160:Receptors, Cytoplasmic and Nuclear; D018000:Receptors, Peptide; C066973:signal sequence receptor
keywords: Endoplasmic reticulum; Membrane protein topology; N-linked glycosylation; Sec61 complex; Translocon-associated proteins