title: Transient covalent interactions of newly synthesized thyroglobulin with oxidoreductases of the endoplasmic reticulum.
abstract: Newly synthesized thyroglobulin (Tg), the thyroid prohormone, forms detectable high molecular weight mixed disulfide adducts: until now, only Tg "adduct B" was identified as primarily engaging the endoplasmic reticulum oxidoreductases ERp57 and protein disulfide isomerase. Here, we demonstrate that the faster migrating Tg adduct C primarily engages the CaBP1/P5 oxidoreductase, whereas the slower migrating Tg adduct A primarily engages ERp72. Upon siRNA-mediated knockdown of CaBP1/P5 or ERp72, adducts C or A, respectively, are decreased. Within the three Tg adduct bands that do not exhibit a precursor-product relationship, Tg exhibits distinct oxidation patterns. We present evidence suggesting that disulfide maturation occurs within Tg monomers engaged in each of the adduct bands. Moreover, the same Tg substrate molecules can form simultaneous mixed disulfides with both CaBP1/P5 and protein disulfide isomerase, although these are generally viewed as components of distinct oxidoreductase-chaperone protein complexes. Such substrate-oxidoreductase combinations offer Tg the potential for simultaneous oxidative maturation along different parallel tracks leading to the native state.
authors.affiliation: Laboratorio di Patologia Generale, Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, 73100 Lecce, Italy,. Electronic address: bruno.dijeso@unisalento.it.
authors.forename: Bruno
authors.initials: B
authors.lastname: Di Jeso
authors.affiliation: Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Morishita
authors.affiliation: Laboratorio di Patologia Generale, Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Università del Salento, 73100 Lecce, Italy.
authors.forename: Antonella S
authors.initials: AS
authors.lastname: Treglia
authors.affiliation: Laboratorio di Anatomia Umana, Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Universita' del Salento, 73100 Lecce, Italy, and.
authors.forename: Dario D
authors.initials: DD
authors.lastname: Lofrumento
authors.affiliation: Laboratorio di Anatomia Umana, Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali, Universita' del Salento, 73100 Lecce, Italy, and.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Nicolardi
authors.affiliation: Dipartimento di Scienze Mediche Traslazionali e Istituto di Endocrinologia ed Oncologia Sperimentale, Centro Nazionale delle Ricerche, Università Federico II, 80131 Napoli, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Beguinot
authors.affiliation: Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105.
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Kellogg
authors.affiliation: Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan 48105,. Electronic address: parvan@umich.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Arvan
mesh_terms: D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004220:Disulfides / Q000378:metabolism; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000235:genetics / Q000378:metabolism*; D013954:Thyroglobulin / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D002135:Calcium-Binding Proteins; D004220:Disulfides; D008562:Membrane Glycoproteins; D046912:Multiprotein Complexes; C062477:endoplasmic reticulum glycoprotein p72; D013954:Thyroglobulin; C085577:Ca2+-binding protein-1; D019704:Protein Disulfide-Isomerases; C085868:PDIA3 protein, human
keywords: Disulfide; Endoplasmic Reticulum (ER); Molecular Chaperone; Protein Folding; Thyroid