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Mol Cell. 2004 Oct 8;16(1):59-68.

Drp-1-dependent division of the mitochondrial network blocks intraorganellar Ca2+ waves and protects against Ca2+-mediated apoptosis.

Author information

1
Department of Experimental and Diagnostic Medicine, Section of General Pathology and Interdisciplinary Center for the Study of Inflammation, University of Ferrara, 44100 Ferrara, Italy.

Abstract

By transiently or stably overexpressing the mitochondrial fission factor dynamin-related protein-1 (Drp-1), we evaluated the role of mitochondrial division in organelle Ca2+ homeostasis and apoptotic signaling. Quantitative 3D digital microscopy revealed a split mitochondrial network in Drp-1-overexpressing cells without changes in cell viability. High-speed mitochondrial [Ca2+] ([Ca2+]m) imaging revealed propagating intramitochondrial Ca2+ waves in intact cells, which were blocked in the Drp-1-fragmented network, leaving a fraction of individual mitochondria without substantial [Ca2+]m elevation. Consequently, in Drp-1-expressing cells the apoptotic efficacy of ceramide, which causes a Ca2+-dependent perturbation of mitochondrial structure and function, was drastically reduced. Conversely, the sensitivity to staurosporine-induced apoptosis, previously shown to be directly triggered by Drp-1-dependent recruitment of proapoptotic proteins to mitochondria, was enhanced. These results demonstrate that the regulated process of mitochondrial fusion and fission controls the spatiotemporal properties of mitochondrial Ca2+ responses and, thus, physiological and pathological consequences of cellular Ca2+ signals.

PMID:
15469822
DOI:
10.1016/j.molcel.2004.09.026
[Indexed for MEDLINE]
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