Potokar M, Milisav I, Kreft M, Stenovec M, Zorec R
Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Medical Faculty Ljubljana, Zaloska 4, Slovenia.
FEBS Lett. 2003 Jun 5;544(1-3):153-9. doi: 10.1016/s0014-5793(03)00494-0.
Caspase-9 is an apoptosis initiator protease activated as a response to the mitochondrial damage in the cytoplasmic complex apoptosome. By fluorescence labelling of proteins, confocal microscopy and subcellular fractionations we demonstrate that caspase-9 is in the cytoplasm of non-apoptotic pituitary cells. The activation of apoptosis with rotenone triggers the redistribution of caspase-9 to mitochondria. Experiments using the general caspase inhibitor z-VAD.fmk and the specific caspase-9 inhibitor z-LEHD.fmk show that the caspase-9 redistribution is a regulated process and requires the activity of a caspase other than the caspase-9. We propose that this spatial regulation is required to control the activity of caspase-9.