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Instytut Biologii Doświadczalnej im. Marcelego Nenckiego PAN ; Universität Bonn
Contributor:Szewczyk, Adam (1960- ) : Supervisor ; Kunz, Wolfram S. : Supervisor ; Kulawiak, Bogusz : Assistant supervisor
Publisher:Nencki Institute of Experimental Biology PAS
Place of publishing: Date issued/created: Description:165 pages : illustrations ; 30 cm ; Bibliography ; Summmary in Polish
Degree grantor:Instytut Biologii Doświadczalnej im. Marcelego Nenckiego PAN
Type of object: Subject and Keywords:BK channels ; Carbon monoxide ; Carbon monoxide releasing molecules ; Cytochrome c oxidase ; Mitochondria ; Potassium channels
Abstract:The defining property of mitochondria – generation of mitochondrial membrane potential –interlinks the metabolic and signaling functions of this organelle. Mitochondrial large- conductance calcium-activated potassium channels (mitoBK) execute its fine regulation by allowing the controlled influx of potassium ions into the mitochondrial matrix. This functionendows them with unique properties, resulting in a cytoprotective phenomenon of mitoBKactivation in ischemia-reperfusion injury. The functional and structural interaction of mitoBKchannels with the electron transfer chain, and in particular, its terminal enzyme cytochrome c oxidase (COX), can be one of its molecular mechanisms.To investigate the interaction between the COX and mitoBK channels, different COX-deficientcellular models were employed. Specifically, human astrocytoma cells were depleted ofmitochondrial DNA (mtDNA) by the treatment with 2’,3’-dideoxycytidine. The comparison ofthe protein complexes formed by the mitoBK and COX in the mtDNA-depleted and WTastrocytoma cells identified the interaction of the pore-forming mitoBK subunit with the COX-containing complexes and respirasomes. Furthermore, downregulation of mitoBK-α subunits on both protein and mRNA levels occurred upon mtDNA-induced COX deficiency. Theanalysis of the retrograde signaling pathways induced by the mtDNA depletion in the mtDNA-depleted astrocytoma cells showed activation of the integrated stress response signaling.Human dermal fibroblasts with a mutation in the structural COX subunit – COX8A – were usedas another cellular model with a deficiency in COX. The organization of the electron transportchain was characterized in the COX8A-deficient fibroblasts and HEK293T cells with CRISPR/Cas9 induced mutations in COX8A and ensuing COX deficiency, identifying that theresidual COX was stabilized in the respirasomes. The decrease in the protein amount of mitoBKpore-forming subunit, as well as its protein complexes, was observed.To follow the systemic implications of this coupling, the effect of a gaseous transmitter carbonmonoxide (CO), putatively targeting both COX and mitoBK, was assessed in the patch-clampstudies. While direct application of CO-saturated solution has not exerted significantmodulation of the mitoBK channel activity, patch perfusion with CO-releasing moleculesinduced pleiotropic effects. Perfusion with heme and hemin inhibited mitoBK channels. Thesubsequent application of CO-saturated solution released this inhibition, activating mitoBKchannels in the presence of heme
Resource type: Detailed Resource Type: Source: Language: Language of abstract: Digitizing institution:Nencki Institute of Experimental Biology of the Polish Academy of Sciences
Original in:Library of the Nencki Institute of Experimental Biology PAS
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