• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Une approche afin de produire les différentes conformations de caspase-7 tout en contrôlant l'induction de l'apoptose

Tremblay, Alexandre January 2011 (has links)
Caspase-7 is a member of a family of cysteine proteases that includes apoptotic initiators (caspases-8, -9 and -10) and executors (caspases-3, -6 and -7). During apoptosis, executioner caspases are cleaved by initiator caspases either by the extrinsic (death receptors) or by the intrinsic (mitochondrial) pathway of caspase activation. Caspase-7 is an obligate dimer in the cell and cleavage of the interdomain connector (IDC), which split the catalytic domain in two subunits, at either site 1 or site 2 allows the conversion of the enzyme from the zymogen (inactive) state to the active state through a conformation switch that leads to the creation of a substrate binding pocket and the catalytic site. During caspase-7 activation, a 23-residue N-terminal peptide is also cleaved. Consequently, caspase-7 displays different N-terminal residues from those of its zymogen. This can change the stability of caspase-7 according to the N-end rule, which relates the half-life of a protein with the residue presented at its N-terminus. This degradation pathway controls the ubiquitination of the protein based on the N-terminus. To replicate the different forms of caspase-7 produced during its activation process in a controlled manner, a TEV protease cleavage site [ENLYFQ[arrow down](S/A)] was strategically inserted to mimic the different possibilities of IDC cleavage: 1) cleavage at site 1 only, 2) cleavage at site 2 only, or 3) a double cleavage. This was done in order to obtain the N-terminal residues normally presented during the cleavage of caspase-7. These constructions have been also optimized to preserve the proteolytic activity of the enzyme with as little change as possible to the length of the IDC. These constructs were cleaved by TEV protease in vitro and in cellulo and allowed the activation of apoptosis. Furthermore, the cellular half-life of caspase-7 seems to be changed by its cleavage. In conclusion, we have developed an interesting tool for the study of caspase-7.

Page generated in 0.0333 seconds