TBK1 and diabetes mellitus: Subsequently, using retro sequence andall-D-amino acid C-peptideenantiomers, Ido et al. [9] suggestedthat C-peptide-induced improvements in nerve function and vascular permeabilityblood flow in diabetes through increases in Na+,K+-ATPaseactivity did not result from C-peptide binding in a stereospecific manner to areceptor.