Figure 1.

The Rim101 pathway mediates a response to lipid stress: adaptation or necrosis. Lipid stress is sensed by the Rim21-sensing complex consisting of Rim8, Rim9, Rim 21 and Dfg16. The sensing complex triggers activation of the Rim101 pathway which depends on ESCRT III. The cysteine-protease Rim13 cleaves the carboxy-terminus of Rim101 and thus activates it as a transcriptional repressor. Activated Rim101 regulates gene expression of NRG1 and RSB1 among others. RSB1 itself encodes a sphingoid long chain base transporter. Rsb1 also regulates PM-flippase (Yor1) and floppase activities (Dnf1 and Dnf2) via Lem3. This may facilitate adaption to PM-lipid stress or trigger necrotic cell death.