Document Type
Article
Publication Date
2-17-2005
Department
Biology
Abstract
When mammalian mitochondria are exposed to high calcium and phosphate, a massive swelling, uncoupling of respiration, and release of cytochrome c occur. These changes are mediated by opening of the mitochondrial permeability transition pore (MPTP). Activation of the MPTP in vivo in response to hypoxic and oxidative stress leads to necrotic and apoptotic cell death. Considering that embryos of the brine shrimp Artemia franciscana tolerate anoxia for years, we investigated the MPTP in this crustacean to reveal whether pore opening occurs. Minimum molecular constituents of the regulated MPTP in mammals are believed to be the voltage-dependent anion channel, the adenine nucleotide translocators, and cyclophilin D. Western blot analysis revealed that mitochondria from A. franciscana possess all three required components. When measured with a calcium-sensitive fluorescent probe, rat liver mitochondria are shown to release matrix calcium after addition of ≥100 μM extramitochondrial calcium (MPTP opening), whereas brine shrimp mitochondria continue to take up extramitochondrial calcium and do not release internal stores even up to 1.0 mM exogenously added calcium (no MPTP opening). Furthermore, no swelling of A. franciscana mitochondria in response to added calcium was observed, and no release of cytochrome c could be detected. HgCl2-dependent swelling and cytochrome c release were readily confirmed, which is consistent with the presence of an “unregulated pore.” Although the absence of a regulated MPTP in A. franciscana mitochondria could contribute to the extreme hypoxia tolerance in this species, we speculate that absence of the regulated MPTP may be a general feature of invertebrates.
Original Publication Information
Menze MA, Hutchinson K, Laborde SM, Hand SC. Mitochondrial permeability transition in the crustacean Artemia franciscana: absence of a calcium-regulated pore in the face of profound calcium storage. Am J Physiol Regul Integr Comp Physiol. 2005 Jul;289(1):R68-76.
ThinkIR Citation
Menze, Michael; Hutchinson, Kirk; Laborde, Susan; and Hand, Steven, "Mitochondrial permeability transition in the crustacean Artemia franciscana : absence of a calcium-regulated pore in the face of profound calcium storage." (2005). Faculty and Staff Scholarship. 118.
https://ir.library.louisville.edu/faculty/118
DOI
10.1152/ajpregu.00844.2004
ORCID
0000-0003-1072-5462
