A conserved ER-membrane protein complex facilitates phospholipid exchange between the ER and mitochondria.

Tuesday, October 09, 2012 — Poster Session I
1:00 p.m. – 3:00 p.m	Natcher Conference Center, Building 45	NIDDK	BIOCHEM-8

* FARE Award Winner

Authors

• S. Lahiri
• J.T. Chao
• S. Tavasolli
• B.P. Young
• C.J. Loewen
• W.A. Prinz

Abstract

Mitochondrial membrane biogenesis requires phospholipid transfer from the endoplasmic reticulum (ER) to mitochondria. Transfer is thought to occur at regions of close contact of these organelles and to be nonvesicular but the mechanism is not known. Here we show that a S. cerevisae strain missing multiple components of the conserved ER-membrane proteins complex (EMC) have reduced phosphatidylserine (PS) transport from the ER to mitochondria. Cells lacking EMC proteins and a protein that is a member of a complex that tethers ER and mitochondria (the ER-mitochondria encounter structure, ERMES) were not viable and PS transfer to mitochondria was almost completely abolished. These defects were corrected by expression of a protein that artificially tethers the ER to mitochondria. Our findings suggest that the EMC complex facilitates ER to mitochondria PS transport by promoting ER-mitochondria tethering and that phospholipid exchange between the ER and mitochondria is an essential process.

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