A Mitochondria-Specific Orange/Near-Infrared-Emissive Fluorescent Probe for Dual-Imaging of Viscosity and H_(2)0_(2) in Inflammation and Tumor Models

Elucidating the intrinsic relationship between viscosity/H_(2)0_(2) and mitochondria-associated diseases remains a great challenge owing to the lack of research on multiple diseases models,such as inflammation and malignant tumor models.In this work,we have developed a mitochondria-specific orange/near-infrared-emissive fluorescent probe TTPB,for dual-imaging of viscosity and H_(2)0_(2) levels in two different channels.The probe exhibited a remarkable response to viscosity with NIR emission round 666 nm,and was highly sensitive to H_(2)0_(2) in orange channel with emission peak at 586 nm.Moreover,TTPB has good mitochondria-specific ability and permits individual detecting of viscosity in NIR channels and H_(2)0_(2) levels in orange channel in living cells.More notably,TTPB was successfully applied to simultaneously image the viscosity and H_(2)0_(2) levels in inflammation and cancer models.

Both metaxin and Tom20 together with two mitochondria-specific motifs support mitochondrial targeting of dual-targeting AtSufE1

Plant cells have two endosymbiotic organelles,chloroplasts,and mitochondria.These organelles perform specific functions that depend on organelle-specific proteins.The majority of chloroplast and mitochondrial proteins are specifically imported by the transit peptide and presequence,respectively.However,a significant number of proteins are also dually targeted to these two organelles.Currently,it is not fully understood how proteins are dually targeted to both chloroplasts and mitochondria.In this study,the mechanism underlying mitochondrial targeting of dual targeting At Suf E1 in Arabidopsis was elucidated.The N-terminal fragment containing 80 residues of AtSufE1(AtSufE1N80)was sufficient to confer dual targeting of reporter protein,At SufE1N80:GFP,in protoplasts.Two sequence motifs,two arginine residues at 15and 21positions,and amino acid(aa)sequence motif AKTLLLRPLK from the 31to 40aa position,were responsible for targeting to mitochondria a portion of reporter proteins amid the chloroplast targeting.The sequence motif PSEVPFRRT from the 41 stto 50 thaa position constitutes a common motif for targeting to both chloroplasts and mitochondria.For mitochondrial import of At Suf E1:N80,Metaxin played a critical role.In addition,Bi FC and protein pull-down experiments showed that At Suf E1N80 specifically interacts with import receptors,Metaxin and Tom20.The interaction of At Suf E1N80 with Metaxin was required for the interaction with Tom20.Based on these results,we propose that mitochondrial targeting of dual-targeting At Suf E1 is mediated by both mitochondria-specific and common sequence motifs in the signal sequence through the interaction with import receptors,Metaxin and Tom20,in a successive manner.