title: Structures and functions of protein disulfide isomerase family members involved in proteostasis in the endoplasmic reticulum.
abstract: The endoplasmic reticulum (ER) is an essential cellular compartment in which an enormous number of secretory and cell surface membrane proteins are synthesized and subjected to cotranslational or posttranslational modifications, such as glycosylation and disulfide bond formation. Proper maintenance of ER protein homeostasis (sometimes termed proteostasis) is essential to avoid cellular stresses and diseases caused by abnormal proteins. Accumulating knowledge of cysteine-based redox reactions catalyzed by members of the protein disulfide isomerase (PDI) family has revealed that these enzymes play pivotal roles in productive protein folding accompanied by disulfide formation, as well as efficient ER-associated degradation accompanied by disulfide reduction. Each of PDI family members forms a protein-protein interaction with a preferential partner to fulfill a distinct function. Multiple redox pathways that utilize PDIs appear to function synergistically to attain the highest quality and productivity of the ER, even under various stress conditions. This review describes the structures, physiological functions, and cooperative actions of several essential PDIs, and provides important insights into the elaborate proteostatic mechanisms that have evolved in the extremely active and stress-sensitive ER.
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Okumura
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kadokura
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan. Electronic address: kinaba@tagen.tohoku.ac.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Inaba
mesh_terms: D000818:Animals; D004721:Endoplasmic Reticulum / Q000502:physiology*; D060746:Endoplasmic Reticulum-Associated Degradation; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D011487:Protein Conformation; D019704:Protein Disulfide-Isomerases / Q000737:chemistry* / Q000378:metabolism*; D017510:Protein Folding; D013329:Structure-Activity Relationship
chemical_list: D019704:Protein Disulfide-Isomerases
keywords: Disulfide bond; ER quality control; ER-associated degradation; Oxidative protein folding; PDI family