02 BOOK OF ABSTRACTS .indd

p30103
The Bcl-2 family members: mediators of cathepsininduced
apoptosis
Ana Petelin 1 , Lea Boji~ 1 , Gabriela Droga Mazovec 1 , Rok Romih 2 ,
Veronika Stoka 1 , Vito Turk 1 and Boris Turk 1
1
Department of Biochemistry and Molecular Biology, Jo`ef Stefan Institute, Ljubljana,
Slovenia; 2 Institute for Cells Biology, Medicine Faculty, Ljubljana, Slovenia
Programmed cell death is the major mechanism by which multicellular organisms
preserves tissue homeostasis and remove infected, damaged or potentially dangerous
cells (Hengartner, 2000). Caspases, a family of cysteine peptidases, play a major
role in apoptosis execution. In addition apoptosis was found to be triggered by
the leakage of cathepsins from lysosomes to the cytosol (Leist et al., 2001; Turk
et al., 2002). In this work we show by several methods that the neuronal cell line
SH-SY5Y undergone apoptosis after selective lysosomal permeabilization induced
with LeuLeuOMe. Thus included morphological changes, caspase-3 activation,
PARP cleavage, presence of cathepsins in the cytosol and cytochrome c release.
Specifically, lysosomal peptidases were released into the cytosol thus cleaving the
proapoptotic Bcl-2 homologue Bid and degrading the antiapoptotic Bcl-2 homologue
Bcl-2. Lysosomal rupture after LeuLeuOMe treatment was confirmed by LysoTracker
Green-uptake method and was not prevented neither by E-64d, a general inhibitor
of papain-like cysteine peptidases nor by z-VAD-fmk, a general caspase inhibitor.
Hengartner, M.O. (2000) Nature 407, 770-776
Leist, M., Jäätela, M. (2001) Nat Rev Mol Cell Biol 2, 589-598
Turk, B., Stoka, V., Rozman-Punger~ar, J., Cirman, T., Droga-Mazovec,
G., Ore{i}, K., Turk, V. (2002) Biol Chem 383, 1035-1044