Sac1 interaction proteomics of ALFA Sac1 and mutants

ABSTRACT: Sphingolipids are structural membrane components that also function in cellular stress responses. The serine palmitoyl-transferase (SPT) catalyzes the rate limiting step in sphingolipid biogenesis. Its activity is tightly regulated through multiple bind-ing partners, including Tsc3, Orm proteins, ceramides, and the phosphatidylinositol-4-phosphate (PI4P) phosphatase Sac1. The structural organization and regulatory mechanisms of this complex are not yet understood. Here, we report the high-resolution cryo-EM structures of the yeast SPT in complex with Tsc3 and Orm1 (SPOT) as dimers and monomers and a monomeric complex further carrying Sac1 (SPOTS). In all complexes, the tight interaction of the down-stream metabolite ceramide and Orm1 reveals the ceramide dependent inhibition. Additionally, observation of ceramide and ergosterol binding suggests a co-regulation of sphingolipid biogenesis and sterol metabolism within the SPOTS com-plex.

INSTRUMENT(S):

ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast)

SUBMITTER: Florian Fröhlich  

LAB HEAD: Florian Fröhlich

PROVIDER: PXD044586 | Pride | 2023-10-24

REPOSITORIES: Pride