title: Efficient IgM assembly and secretion require the plasma cell induced endoplasmic reticulum protein pERp1.
abstract: Plasma cells daily secrete their own mass in antibodies, which fold and assemble in the endoplasmic reticulum (ER). To reach these levels, cells require pERp1, a novel lymphocyte-specific small ER-resident protein, which attains expression levels as high as BiP when B cells differentiate into plasma cells. Although pERp1 has no homology with known ER proteins, it does contain a CXXC motif typical for oxidoreductases. In steady state, the CXXC cysteines are locked by two parallel disulfide bonds with a downstream C(X)(6)C motif, and pERp1 displays only modest oxidoreductase activity. pERp1 emerged as a dedicated folding factor for IgM, associating with both heavy and light chains and promoting assembly and secretion of mature IgM.
authors.affiliation: Cellular Protein Chemistry and Biomolecular Mass Spectrometry, Bijvoet Center for Biomolecular Research, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands.
authors.forename: Eelco
authors.initials: E
authors.lastname: van Anken
authors.forename: Florentina
authors.initials: F
authors.lastname: Pena
authors.forename: Nicole
authors.initials: N
authors.lastname: Hafkemeijer
authors.forename: Chantal
authors.initials: C
authors.lastname: Christis
authors.forename: Edwin P
authors.initials: EP
authors.lastname: Romijn
authors.forename: Ulla
authors.initials: U
authors.lastname: Grauschopf
authors.forename: Viola M J
authors.initials: VM
authors.lastname: Oorschot
authors.forename: Thomas
authors.initials: T
authors.lastname: Pertel
authors.forename: Sander
authors.initials: S
authors.lastname: Engels
authors.forename: Ari
authors.initials: A
authors.lastname: Ora
authors.forename: Viorica
authors.initials: V
authors.lastname: Lástun
authors.forename: Rudi
authors.initials: R
authors.lastname: Glockshuber
authors.forename: Judith
authors.initials: J
authors.lastname: Klumperman
authors.forename: Albert J R
authors.initials: AJ
authors.lastname: Heck
authors.forename: Jeremy
authors.initials: J
authors.lastname: Luban
authors.forename: Ineke
authors.initials: I
authors.lastname: Braakman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism / Q000648:ultrastructure; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D015180:Electrophoresis, Gel, Two-Dimensional; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D006367:HeLa Cells; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007075:Immunoglobulin M / Q000378:metabolism*; D013058:Mass Spectrometry; D051379:Mice; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D010088:Oxidoreductases / Q000378:metabolism; D010950:Plasma Cells / Q000166:cytology / Q000378:metabolism*; D034622:RNA Interference; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; D007075:Immunoglobulin M; D018832:Molecular Chaperones; D013438:Sulfhydryl Compounds; D010088:Oxidoreductases