FRET evidence that an isoform of caspase-7 binds but does not cleave its substrate.

Content Provider	Semantic Scholar
Author	Li, Isaac T. S. Pham, Elizabeth Chiang, Jason Truong, Kevin
Copyright Year	2008
Abstract	A caspase-7 biosensor (vDEVDc) based on FRET (fluorescence resonance energy transfer) was used to study the proteolytic properties of caspase-7, an executioner protease in cellular apoptosis. An active isoform of caspase-7 with the 56 N-terminal residues truncated (57casp7) cleaved vDEVDc at the recognition sequence, resulting in a FRET efficiency decrease of 61%. In contrast, an isoform with the 23 N-terminal residues truncated (24casp7) bound to vDEVDc but did not cleave the substrate, resulting in a FRET increase of 15%. Kinetic results showed an exponential substrate cleavage and binding curve for the 57casp7 and 24casp7 isoforms, respectively. FRET changes of the vDEVDc biosensor were also monitored in cos-7 cells upon STS-induced apoptosis. Finally, we modeled caspase-7 binding to vDEVDc and estimated a FRET emission ratio increase of 31.7%, which agrees with the 15% experimental result. We showed that two differently truncated isoforms of caspase-7 exhibit different enzymatic properties, namely binding by 24casp7 and hydrolysis by 57casp7.
File Format	PDF HTM / HTML
DOI	10.1016/j.bbrc.2008.06.034
PubMed reference number	18571498
Journal	Medline
Volume Number	373
Issue Number	2
Alternate Webpage(s)	http://www.individual.utoronto.ca/ktruong/papers/IEEEconfCaspase.pdf
Alternate Webpage(s)	http://apel.ibbme.utoronto.ca/apel/publications/li_pham_chiang_truong.pdf
Journal	Biochemical and biophysical research communications
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article