Mechanism and cellular function of direct membrane binding by the ESCRT and ERES-associated Ca 2+ -sensor ALG-2

• DOI: 10.1073/pnas.2318046121
• Publication Date: 2024-02-22T18:48:56Z
• Authors: Sankalp Shukla; Wei Chen; Shanlin Rao; Serim Yang; Chenxi Ou; Kevin P. Larsen; Gerhard Hummer; Phyllis I. Hanson; James H. Hurley
• Keywords: ESCRT; COPII; Vesicular Transport Proteins

Apoptosis linked Gene-2 (ALG-2) is a multifunctional intracellular Ca 2+ sensor and the archetypal member of penta-EF hand protein family. ALG-2 functions in repair damage to both plasma lysosome membranes COPII-dependent budding at e ndoplasmic r eticulum xit s ites (ERES). In presence , binds ESCRT-I ALIX membrane SEC31A ERES. also directly acidic by combination electrostatic hydrophobic interactions. By combining giant unilamellar vesicle-based experiments molecular dynamics simulations, we show that charge-reversed mutants these locations disrupt recruitment. binding have reduced or abrogated ERES localization response Thapsigargin-induced release but still localize lysosomes following lysosomal release. vitro reconstitution shows membrane-binding defect can be rescued ESCRT-I. These data thus reveal nature direct -dependent its interplay with cellular ALG-2.