Miro1-mediated mitochondrial positioning supports subcellular redox status

Abstract

Mitochondria are strategically trafficked throughout the cell by the action of microtubule motors, the actin cytoskeleton and adapter proteins. The intracellular positioning of mitochondria supports subcellular levels of ATP, Ca 2+ and reactive oxygen species (ROS, i.e. hydrogen peroxide, H 2 O 2 ). Previous work from our group showed that deletion of the mitochondrial adapter protein Miro1 leads to perinuclear clustering of mitochondria, leaving the cell periphery devoid of mitochondria which compromises peripheral energy status. Herein, we report that deletion of Miro1 significantly restricts subcellular H 2 O 2 levels to the perinuclear space which directly affects intracellular responses to elevated mitochondrial ROS. Using the genetically encoded H 2 O 2 -responsive fluorescent biosensor HyPer7, we show that the highest levels of subcellular H 2 O 2 map to sites of increased mitochondrial density. Deletion of Miro1 or disruption of microtubule dynamics with Taxol significantly reduces peripheral H 2 O 2 levels. Following inhibition of mitochondrial complex 1 with rotenone we observe elevated spikes of H 2 O 2 in the cell periphery and complementary oxidation of mitochondrial peroxiredoxin 3 (PRX3) and cytosolic peroxiredoxin 2 (PRX2). Conversely, in cells lacking Miro1, rotenone did not increase peripheral H 2 O 2 or PRX2 oxidation but rather lead to increased nuclear H 2 O 2 and an elevated DNA-damage response. Lastly, local levels of HyPer7 oxidation correlate with the size and abundance of focal adhesions (FAs) in MEFs and cells lacking Miro1 have significantly smaller focal adhesions and reduced phosphorylation levels of vinculin and p130Cas compared to Miro1 +/+ MEFs. Together, we present evidence that the intracellular distribution of mitochondria influences subcellular H 2 O 2 levels and local cellular responses dependent on mitochondrial ROS.

Air Plasma-Activated Medium Evokes a Death-Associated Perinuclear Mitochondrial Clustering

“…Precise distributions are essential for energy supply [18,19], the plasma membrane Ca 2+ channel activity [47], Ca 2+ signaling [48][49][50], and hypoxic state and signaling [26][27][28][29]. Moreover, several reports demonstrate a closed relationship between mitochondrial motility and the mitochondria-ER tethering [51], Ca 2+ transport [52], and redox state [53,54]. Our previous works show that mitochondrial fragmentation followed by clustering is essential for apoptotic or nonapoptotic cell death caused by the TRAIL, HePAM, and PAI [12,13,17,32,33].…”

Mitochondrial Fission and Fusion in Tumor Progression to Metastasis

“…The role of ROS in tumor biology is well established as having both tumor promoting and tumor suppressive properties ( Moloney and Cotter, 2018 ). The distinction between these two outcomes is determined by the level of ROS, the duration of exposure, the different species, and where it is produced spatially ( Cameron et al, 2015 ; Moloney and Cotter, 2018 ; Alshaabi et al, 2021 ). A modest increase in ROS can drive important signaling events that promote tumor growth and metastasis however, large increases in ROS are toxic and result in cell death.…”

Epithelial Ablation of Miro1/Rhot1 GTPase Augments Lung Inflammation by Cigarette Smoke

“…To sustain the quality control of the mitochondria, Miro1 (Rhot1) serves as an essential element in mitochondrial quality control. Rhot1 (Miro1) is a calcium-binding membrane-anchored GTPase that is required for the calcium-driven movement of the mitochondria in microtubules, especially during mitophagy [ 1 , 5 , 6 , 7 ]. Miro1 also serves a vital role in mitochondrial dynamics because of its interaction with the Pink1 (PTEN-induced putative kinase 1)/Parkin mitochondrial quality control system by serving as a signal for mitophagy [ 8 , 9 ].…”