title: Mitochondria-Associated Membranes and ER Stress.
abstract: The endoplasmic reticulum (ER) is a crucial organelle for coordinating cellular Ca2+signaling and protein synthesis and folding. Moreover, the dynamic and complex membranous structures constituting the ER allow the formation of contact sites with other organelles and structures, including among others the mitochondria and the plasma membrane (PM). The contact sites that the ER form with mitochondria is a hot topic in research, and the nature of the so-called mitochondria-associated membranes (MAMs) is continuously evolving. The MAMs consist of a proteinaceous tether that physically connects the ER with mitochondria. The MAMs harness the main functions of both organelles to form a specialized subcompartment at the interface of the ER and mitochondria. Under homeostatic conditions, MAMs are crucial for the efficient transfer of Ca2+from the ER to mitochondria, and for proper mitochondria bioenergetics and lipid synthesis. MAMs are also believed to be the master regulators of mitochondrial shape and motility, and to form a crucial site for autophagosome assembly. Not surprisingly, MAMs have been shown to be a hot spot for the transfer of stress signals from the ER to mitochondria, most notably under the conditions of loss of ER proteostasis, by engaging the unfolded protein response (UPR). In this chapter after an introduction on ER biology and ER stress, we will review the emerging and key signaling roles of the MAMs, which have a root in cellular processes and signaling cascades coordinated by the ER.
authors.affiliation: Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, University of Leuven, KU Leuven, 3000, Leuven, Belgium.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: van Vliet
authors.affiliation: Laboratory of Cell Death Research & Therapy, University of Leuven, Campus Gasthuisberg O&N1, Herestraat 49, box 802, 3000, Leuven, Belgium. Patrizia.Agostinis@kuleuven.be.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Agostinis
mesh_terms: D000818:Animals; D000071182:Autophagosomes / Q000502:physiology; D020013:Calcium Signaling / Q000502:physiology; D059865:Endoplasmic Reticulum Stress / Q000502:physiology*; D006801:Humans; D051336:Mitochondrial Membranes / Q000502:physiology*; D017510:Protein Folding; D056811:Unfolded Protein Response / Q000502:physiology