title: Expression of OsBiP4 and OsBiP5 is highly correlated with the endoplasmic reticulum stress response in rice.
abstract: Binding protein (BiP) is a chaperone protein involved in the folding of secretory proteins in the ER lumen. OsBiP1 is constitutively expressed in various tissues, whereas the expression of OsBiP4 and OsBiP5 (OsBiP4&5) is not detected in any tissue under normal conditions. However, expression of OsBiP4&5 was highly and specifically activated under ER stress conditions induced by DTT treatment, OsBiP1 knockdown, OsBiP1 overexpression, OsIRE1 overexpression, or various exogenous recombinant proteins in transgenic rice. In contrast, OsBiP4&5 did not accumulate in OsIRE1 knockdown transgenic rice even after DTT treatment. When the subcellular localization of OsBiP4&5 was investigated in seed endosperm cells under the ER stress condition, OsBiP4&5 were localized to the ER, but did not participate in ER-derived protein body (PB-I) formation in a different manner to OsBiP1. These results indicate that OsBiP4&5 levels were positively correlated with stress levels in the ER. Taken together, these results suggest that OsBiP4&5 are ER stress-related BiP proteins that are regulated by OsIRE1/OsbZIP50 pathway and that they may have a distinct function from that of OsBiP1 in rice.
authors: Functional Transgenic Crops Research Unit, Genetically Modified Organism Research Center, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, Ibaraki, 305-8602, Japan.
authors: Yuhya
authors: Y
authors: Wakasa
authors: Shimpei
authors: S
authors: Hayashi
authors: Fumio
authors: F
authors: Takaiwa
mesh_terms: D000906:Antibodies / Q000276:immunology; D004229:Dithiothreitol / Q000494:pharmacology; D059865:Endoplasmic Reticulum Stress / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D012639:Seeds / Q000235:genetics
chemical_list: D000906:Antibodies; D018832:Molecular Chaperones; D010940:Plant Proteins; D004229:Dithiothreitol