TY  - JOUR
A1  - Hoffmann, Linda S
A1  - Schmidt, Peter M
A1  - Keim, Yvonne
A1  - Hoffmann, Carsten
A1  - Schmidt, Harald H H W
A1  - Stasch, Johannes-Peter
T1  - Fluorescence Dequenching Makes Haem-Free Soluble Guanylate Cyclase Detectable in Living Cells
JF  - PLOS ONE
N2  - In cardiovascular disease, the protective NO/sGC/cGMP signalling-pathway is impaired due to a decreased pool of NO-sensitive haem-containing sGC accompanied by a reciprocal increase in NO-insensitive haem-free sGC. However, no direct method to detect cellular haem-free sGC other than its activation by the new therapeutic class of haem mimetics, such as BAY 58-2667, is available. Here we show that fluorescence dequenching, based on the interaction of the optical active prosthetic haem group and the attached biarsenical fluorophor FlAsH can be used to detect changes in cellular sGC haem status. The partly overlap of the emission spectrum of haem and FlAsH allows energy transfer from the fluorophore to the haem which reduces the intensity of FlAsH fluorescence. Loss of the prosthetic group, e. g. by oxidative stress or by replacement with the haem mimetic BAY 58-2667, prevented the energy transfer resulting in increased fluorescence. Haem loss was corroborated by an observed decrease in NO-induced sGC activity, reduced sGC protein levels, and an increased effect of BAY 58-2667. The use of a haem-free sGC mutant and a biarsenical dye that was not quenched by haem as controls further validated that the increase in fluorescence was due to the loss of the prosthetic haem group. The present approach is based on the cellular expression of an engineered sGC variant limiting is applicability to recombinant expression systems. Nevertheless, it allows to monitor sGC's redox regulation in living cells and future enhancements might be able to extend this approach to in vivo conditions.
KW  - spontaneously hypersensitive-rats
KW  - nitric-oxide
KW  - down-regulation
KW  - energy-transfer
KW  - cyclic-gmp
KW  - protein
KW  - activation
KW  - identification
KW  - in-vivo
KW  - no
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-139631
VL  - 6
IS  - 8
ER  -