SPLICS: a split green fluorescent protein-based contact site sensor for narrow and wide heterotypic organelle juxtaposition

Cell Death Differ. 2018 Jun;25(6):1131-1145. doi: 10.1038/s41418-017-0033-z. Epub 2017 Dec 11.


Contact sites are discrete areas of organelle proximity that coordinate essential physiological processes across membranes, including Ca2+ signaling, lipid biosynthesis, apoptosis, and autophagy. However, tools to easily image inter-organelle proximity over a range of distances in living cells and in vivo are lacking. Here we report a split-GFP-based contact site sensor (SPLICS) engineered to fluoresce when organelles are in proximity. Two SPLICS versions efficiently measured narrow (8-10 nm) and wide (40-50 nm) juxtapositions between endoplasmic reticulum and mitochondria, documenting the existence of at least two types of contact sites in human cells. Narrow and wide ER-mitochondria contact sites responded differently to starvation, ER stress, mitochondrial shape modifications, and changes in the levels of modulators of ER-mitochondria juxtaposition. SPLICS detected contact sites in soma and axons of D. rerio Rohon Beard (RB) sensory neurons in vivo, extending its use to analyses of organelle juxtaposition in the whole animal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis*
  • Autophagy*
  • Calcium Signaling*
  • Endoplasmic Reticulum / genetics
  • Endoplasmic Reticulum / metabolism*
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Mitochondria / genetics
  • Mitochondria / metabolism*
  • Mitochondrial Membranes / metabolism*
  • Zebrafish


  • Green Fluorescent Proteins