title: Endoplasmic reticulum stress-sensing mechanisms in yeast and mammalian cells.
abstract: Upon endoplasmic reticulum (ER) stress, ER-located transmembrane stress sensors evoke diverse protective responses. Although ER stress-dependent activation of the sensor proteins is partly explained through their negative regulation by the ER-located chaperone BiP under non-stress conditions, each of the sensors is also regulated by distinct mechanism(s). For instance, yeast Ire1 is fully activated via its direct interaction with unfolded proteins accumulated in the ER. This insight is consistent with a classical notion that unfolded proteins per se trigger ER-stress responses, while various stress stimuli also seem to activate individual sensors independently of unfolded proteins and in a stimuli-specific manner. These properties may account for the different responses observed under different conditions in mammalian cells, which carry multiple ER-stress sensors.
authors.affiliation: Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kimata
authors.forename: Kenji
authors.initials: K
authors.lastname: Kohno
mesh_terms: D000818:Animals; D004721:Endoplasmic Reticulum / Q000737:chemistry / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D008322:Mammals / Q000378:metabolism*; D058767:Protein Unfolding; D013312:Stress, Physiological; D015003:Yeasts / Q000378:metabolism*
chemical_list: D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins