Split genetically encoded calcium indicators for interorganellar junctions

S Shunit Olszakier (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology) W Wessal Hussein (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology) R Ronit Heinrich (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology) M Michael Andreyanov (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology) A Achinoam Blau (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology) Y Yara Otor (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology) J Jackie Schiller (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology) S Shai Kellner (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology) S Shai Berlin (Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology)

Abstract

Genetically encoded calcium indicators (GECIs) have revolutionized the study of cellular calcium signaling, offering powerful tools for real-time optical monitoring of calcium dynamics. Although contemporary GECIs can be targeted to various organelles, there are no means to obtain active and functional GECIs exclusively at interorganellar junctions. To address this gap, we have developed a toolbox of split versions of green and red GECIs designed to reassemble only when the two “halves” come into proximity. We developed split probes to investigate interorganellar connectivity and activity between mitochondria and the ER (via split-MEGIC) or between the plasma membrane and the ER (via split-sf-MEMBER). We employ the various split-sensors to image neural Ca 2+ activity in vitro and in vivo and, in the process, identify Mito–ER junctions and calcium activity within individual dendritic spines by use of split-MEGIC.

Article Details

Volume / Issue Vol. 122, Issue 20
Published May 20, 2025
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (9)

S

Shunit Olszakier

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology

W

Wessal Hussein

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology

R

Ronit Heinrich

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology

M

Michael Andreyanov

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology

A

Achinoam Blau

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology

Y

Yara Otor

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology

J

Jackie Schiller

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology

S

Shai Kellner

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology

S

Shai Berlin

Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion–Israel Institute of Technology