Sar1, a Novel Regulator of ER-Mitochondrial Contact Sites

Ackema, Karin B. and Prescianotto-Baschong, Cristina and Hench, Jürgen and Wang, Shyi Chyi and Chia, Zhi Hui and Mergentaler, Heidi and Bard, Fredéric and Frank, Stephan and Spang, Anne. (2016) Sar1, a Novel Regulator of ER-Mitochondrial Contact Sites. PLoS ONE, 11 (4). e0154280.

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Endoplasmic reticulum (ER)-mitochondrial contact sites play a pivotal role in exchange of lipids and ions between the two organelles. How size and function of these contact sites are regulated remains elusive. Here we report a previously unanticipated, but conserved role of the small GTPase Sar1 in the regulation of ER-mitochondrial contact site size. Activated Sar1 introduces membrane curvature through its N-terminal amphiphatic helix at the ER-mitochondria interphase and thereby reducing contact size. Conversely, the S. cerevisiae N3-Sar1 mutant, in which curvature induction is decreased, caused an increase in ER-mitochondrial contacts. As a consequence, ER tubules are no longer able to mark the prospective scission site on mitochondria, thereby impairing mitochondrial dynamics. Consistently, blocking mitochondrial fusion partially rescued, whereas deletion of the dynamin-like protein enhanced the phenotype in the sar1D32G mutant. We conclude that Sar1 regulates the size of ER-mitochondria contact sites through its effects on membrane curvature.
Faculties and Departments:05 Faculty of Science > Departement Biozentrum > Growth & Development > Biochemistry (Spang)
UniBasel Contributors:Spang, Anne
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Public Library of Science
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:31 Aug 2018 06:32
Deposited On:22 Nov 2016 10:19

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