Nanopore Technology Branches Out To Detect Protein Phosphorylation Patterns

Strawlike proteins embedded into lipid membranes—known as nanopores—are already invaluable in genomics research. Scientists can sequence DNA by analyzing subtle differences in ionic current that occur as nucleotides thread through the nanopore and partially block ion flow. By applying nanopore technology to proteomics, a research team is now able to detect phosphorylation patterns on proteins that regulate protein activity (Nat. Biotechnol. 2014, DOI: 10.1038/nbt.2799). To coax a protein “camel” through the “eye” of a nanopore needle, Christian B. Rosen, David Rodriguez-Larrea, and Hagan Bayley of the University of Oxford added a short DNA sequence to the C-terminus of the protein thioredoxin. Their technique distinguished whether thioredoxin was phosphorylated in one of two positions, in both positions, or in neither position. The nanopores can determine populations of phosphorylation patterns in hundreds of individual copies of a protein, which is useful information in cancer diagnostic research, although the method currently detects phosphorylation only near the ends of proteins. Other teams have used motor proteins to feed an entire protein through a nanopore, a method Bayley’s group hopes to adapt to overcome the detection limitation. The technology has been patented and licensed to Oxford Nanopore Technologies, a company Bayley founded.