DNA nanodevices map enzymatic activity in organelles

Area of Science:

• Cell Biology
• Biochemistry
• Microbiology

Background:

• Current cellular reporters for enzyme activity often miss minor enzyme populations in specific organelles.
• Subcellular enzyme activity is critical for cellular functions and disease pathogenesis.

Purpose of the Study:

• To develop a novel chemical imaging strategy for selectively interrogating minor, subcellular pools of enzymatic activity.
• To map disulfide reduction within endosomes and identify the enzymes responsible.

Main Methods:

• Developed an organelle-confined chemical detection strategy for enzyme activity imaging.
• Quantitatively mapped disulfide reduction exclusively within endosomes in Caenorhabditis elegans.
• Investigated the role of endosomal enzymes PDI-3 and TRX-1 in disulfide reduction.

Main Results:

• Identified minor populations of PDI-3 and TRX-1 enzymes resident in endosomes mediate disulfide reduction.
• Demonstrated that impeding intra-endosomal disulfide reduction by knocking down TRX-1 protects nematodes from Corynebacterium diphtheriae infection.
• Confirmed TRX-1 mediates endosomal disulfide reduction in human cells.

Conclusions:

• The new reporter strategy enables selective imaging of enzymatic cleavage within organelles.
• Minor pools of endosomal TRX-1 are crucial for protecting against bacterial infection.
• This technology can be applied to study a range of enzymatic reactions in various organelles.