The Rim101 pathway contributes to ER stress adaptation through sensing the state of plasma membrane.

Keisuke Obara, Akio Kihara

The Biochemical journal 2017 Jan 01

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Yeast cells sense alterations in the plasma membrane (PM) lipid asymmetry and external alkalization by the sensor protein Rim21, which functions in the Rim101 pathway. Rim101 signaling is initiated at the PM by the recruitment of the Rim101 signaling complex. The PM physically associates with the cortical endoplasmic reticulum (ER) to form ER-PM contact sites, where several signaling events, lipid exchange, and ion transport take place. In the present study, we investigated the spatial relationship between ER-PM contact sites and the sites of Rim101 signaling. Rim101 signaling mostly proceeds outside ER-PM contact sites in the PM and did not require intact ER-PM contact for its activation. Rather, the Rim101 pathway was constitutively activated by ER-PM contact site disruption, which is known to cause ER stress. ER stress induced by tunicamycin treatment activated the Rim101 pathway. Furthermore, the sensitivity of cells to tunicamycin without ER-PM contact was considerably elevated by the deletion of RIM21. These results suggest that the Rim101 pathway is important for the adaptation to ER stress by compensating for alterations in PM lipid asymmetry induced by ER stress. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

Citation

Keisuke Obara, Akio Kihara. The Rim101 pathway contributes to ER stress adaptation through sensing the state of plasma membrane. The Biochemical journal. 2017 Jan 01;474(1):51-63