Membrane lipids couple synaptotagmin to SNARE-mediated granule fusion in insulin-secreting cells.

ABSTRACT: Insulin secretion depends on the Ca²⁺-regulated fusion of granules with the plasma membrane. A recent model of Ca²⁺-triggered exocytosis in secretory cells proposes that lipids in the plasma membrane couple the calcium sensor Syt1 to the membrane fusion machinery (Kiessling et al., 2018). Specifically, Ca²⁺-mediated binding of Syt1's C2 domains to the cell membrane shifts the membrane-anchored SNARE syntaxin-1a to a more fusogenic conformation, straightening its juxtamembrane linker. To test this model in live cells and extend it to insulin secretion, we enriched INS1 cells with a panel of lipids with different acyl chain compositions. Fluorescence lifetime measurements demonstrate that cells with more disordered membranes show an increase in fusion

SUBMITTER: Amos C 

PROVIDER: S-EPMC10916878 | biostudies-literature | 2024 Mar

REPOSITORIES: biostudies-literature