Activity of the SPCA1 Calcium Pump Couples Sphingomyelin Synthesis to Sorting of Secretory Proteins in the Trans-Golgi Network.

ABSTRACT: How the principal functions of the Golgi apparatus-protein processing, lipid synthesis, and sorting of macromolecules-are integrated to constitute cargo-specific trafficking pathways originating from the trans-Golgi network (TGN) is unknown. Here, we show that the activity of the Golgi localized SPCA1 calcium pump couples sorting and export of secreted proteins to synthesis of new lipid in the TGN membrane. A secreted Ca²⁺-binding protein, Cab45, constitutes the core component of a Ca²⁺-dependent, oligomerization-driven sorting mechanism whereby secreted proteins bound to Cab45 are packaged into a TGN-derived vesicular carrier whose membrane is enriched in sphingomyelin, a lipid implicated in TGN-to-cell surface transport. SPCA1 activity is controlled by the sphingomy

SUBMITTER: Deng Y 

PROVIDER: S-EPMC6261503 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature