title: Co-chaperones of the mammalian endoplasmic reticulum.
abstract: In mammalian cells, the rough endoplasmic reticulum or ER plays a central role in the biogenesis of most extracellular plus many organellar proteins and in cellular calcium homeostasis. Therefore, this organelle comprises molecular chaperones that are involved in import, folding/assembly, export, and degradation of polypeptides in millimolar concentrations. In addition, there are calcium channels/pumps and signal transduction components present in the ER membrane that affect and are affected by these processes. The ER lumenal Hsp70, termed immunoglobulin-heavy chain binding protein or BiP, is the central player in all these activities and involves up to seven different co-chaperones, i.e. ER-membrane integrated as well as ER-lumenal Hsp40s, which are termed ERj or ERdj, and two nucleotide exchange factors.
authors.affiliation: Medical Biochemistry & Molecular Biology, Saarland University, D-66421, Homburg, Germany, armin.melnyk@uks.eu.
authors.forename: Armin
authors.initials: A
authors.lastname: Melnyk
authors.forename: Heiko
authors.initials: H
authors.lastname: Rieger
authors.forename: Richard
authors.initials: R
authors.lastname: Zimmermann
mesh_terms: D000818:Animals; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D050956:HSP40 Heat-Shock Proteins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D017510:Protein Folding; D021381:Protein Transport; D059748:Proteolysis; D015398:Signal Transduction; D013329:Structure-Activity Relationship
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones