“…Drp1 appears to be responsible for this fragmented phenotype as studies have demonstrated that ablation of Drp1 reduces mitochondrial fragmentation during apoptosis (Estaquier et al, 2007;Frank et al, 2001;Karbowski et al, 2002;Sugioka et al, 2004), while overexpression of dominant negative Drp1 also prevents apoptosis-induced mitochondrial fragmentation (Arnoult et al, 2005b;Frank et al, 2001 Cribbs et al, 2007). However, following a death stimulus such as staurosporine, the phosphatase calcineurin dephosphorylates Drp-1, triggering its translocation from the cytosol to mitochondria, thus increasing fission (Cereghetti et al, 2008;Cribbs et al, 2007). In addition, overexpression of the BH3-only protein Bik induces Drp1-dependent mitochondrial fission by a pathway dependent on calcium signalling (Germain et al, 2005).…”