Nguyen, Tammy TLewandowska, AgnieszkaChoi, Jae-YeonMarkgraf, Daniel FJunker, MircoBilgin, MesutEjsing, Christer SVoelker, Dennis RRapoport, Tom AShaw, Janet M2014-02-132012Nguyen, Tammy T, Agnieszka Lewandowska, Jae-Yeon Choi, Daniel F Markgraf, Mirco Junker, Mesut Bilgin, Christer S Ejsing, Dennis R Voelker, Tom A Rapoport, and Janet M Shaw. 2012. “Gem1 and ERMES Do Not Directly Affect Phosphatidylserine Transport from ER to Mitochondria or Mitochondrial Inheritance.” Traffic (Copenhagen, Denmark) 13 (6): 880-890. doi:10.1111/j.1600-0854.2012.01352.x. http://dx.doi.org/10.1111/j.1600-0854.2012.01352.x.1398-9219http://nrs.harvard.edu/urn-3:HUL.InstRepos:11708644In yeast, a protein complex termed the ER-Mitochondria Encounter Structure (ERMES) tethers mitochondria to the endoplasmic reticulum. ERMES proteins are implicated in a variety of cellular functions including phospholipid synthesis, mitochondrial protein import, mitochondrial attachment to actin, polarized mitochondrial movement into daughter cells during division, and maintenance of mitochondrial DNA (mtDNA). The mitochondrial-anchored Gem1 GTPase has been proposed to regulate ERMES functions. Here, we show that ERMES and Gem1 have no direct role in the transport of phosphatidylserine (PS) from the ER to mitochondria during the synthesis of phosphatidylethanolamine (PE), as PS to PE conversion is not affected in ERMES or gem1 mutants. In addition, we report that mitochondrial inheritance defects in ERMES mutants are a secondary consequence of mitochondrial morphology defects, arguing against a primary role for ERMES in mitochondrial association with actin and mitochondrial movement. Finally, we show that ERMES complexes are long-lived, and do not depend on the presence of Gem1. Our findings suggest that the ERMES complex may have primarily a structural role in maintaining mitochondrial morphology.en-USERMESER-mitochondriaGem1 GTPaseMdm10Mdm12Mdm34membrane contact site (MCS)mitochondrial movement and inheritancemitochondrial phospholipidsMmm1yeast MiroJournal Article2014-02-1310.1111/j.1600-0854.2012.01352.x