scholarly journals Mieap forms membraneless organelles to compartmentalize and facilitate cardiolipin metabolism

2020 ◽  
Author(s):  
Naoki Ikari ◽  
Katsuko Honjo ◽  
Yoko Sagami ◽  
Yasuyuki Nakamura ◽  
Hirofumi Arakawa
Keyword(s):  
Quality Control ◽  
Critical Role ◽  
Enzymatic Reactions ◽  
Liquid Droplets ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Quality Control ◽  
Kidney Mitochondria ◽  
Intrinsically Disordered ◽  
Liver And Kidney ◽  
Inducible Protein

AbstractLiquid droplets function as membraneless organelles that compartmentalize and facilitate efficient biological reactions in cells. They are formed by proteins with an intrinsically disordered region(s) (IDR) via liquid–liquid phase separation. Mieap/SPATA18, a p53-inducible protein, plays a critical role in the suppression of human and murine colorectal tumors via mitochondrial quality control. However, the regulatory mechanism underlying this process remains unclear. Here, we report that Mieap is an IDR-containing protein that drives the formation of liquid droplets in the mitochondria. Mieap liquid droplets (MLDs) specifically phase separate the mitochondrial phospholipid cardiolipin. Lipidomic analysis of cardiolipin suggested that Mieap promotes enzymatic reactions involved in cardiolipin metabolism, including biosynthesis and remodeling. Accordingly, four cardiolipin biosynthesis enzymes, TAMM41, PGS1, PTPMT1, and CRLS1, and two remodeling enzymes, PLA2G6 and TAZ, are phase separated by MLDs. Mieap-deficient mice exhibited altered cristae structure in the liver and kidney mitochondria and a trend of obesity. These results suggest that Mieap drives the formation of membraneless organelles to compartmentalize and promotes cardiolipin metabolism at the inner mitochondrial membrane, thus playing a possible role in mitochondrial quality control.

scholarly journals Mieap forms membraneless organelles to compartmentalize and facilitate cardiolipin metabolism

2021 ◽  
Author(s):  
Naoki Ikari ◽  
Katsuko Honjo ◽  
Yoko Sagami ◽  
Yasuyuki Nakamura ◽  
Hirofumi Arakawa
Keyword(s):  
Quality Control ◽  
Enzymatic Reactions ◽  
Liquid Droplets ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Quality Control ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Inducible Protein ◽  
Deficient Mice ◽  
Liquid Liquid Phase Separation

Abstract Liquid droplets function as membraneless organelles that compartmentalize and facilitate efficient biological reactions. They are formed by proteins with intrinsically disordered regions (IDRs) via liquid–liquid phase separation. Mieap/SPATA18, a p53-inducible protein, participates in suppression of colorectal tumors by promoting mitochondrial quality control. However, the regulatory mechanism involved remains unclear. Here, we report that Mieap is an IDR-containing protein that drives formation of liquid droplets in mitochondria. Mieap liquid droplets specifically phase separate the mitochondrial phospholipid, cardiolipin. Lipidomic analysis of cardiolipin suggests that Mieap promotes enzymatic reactions involved in cardiolipin metabolism, including biosynthesis and remodeling. Accordingly, four cardiolipin biosynthetic enzymes, TAMM41, PGS1, PTPMT1, and CRLS1, and two remodeling enzymes, PLA2G6 and TAZ, are phase-separated by Mieap liquid droplets. Mieap-deficient mice exhibit altered crista structure in mitochondria of various tissues, including brown fat, and tend to become obese. These results suggest that Mieap drives formation of membraneless organelles to compartmentalize and promote cardiolipin metabolism at the inner mitochondrial membrane, thus potentially contributing to mitochondrial quality control.

scholarly journals Receptor-mediated mitophagy regulates EPO production and protects against renal anemia

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Guangfeng Geng ◽  
Jinhua Liu ◽  
Changlu Xu ◽  
Yandong yan Pei ◽  
Linbo Chen ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Quality Control ◽  
Therapeutic Strategy ◽  
Inflammatory Responses ◽  
Critical Role ◽  
Renal Anemia ◽  
Inflammatory Factors ◽  
Oxygen Species ◽  
Mitochondrial Quality Control ◽  
Hematopoietic Disorders

Erythropoietin (EPO) drives erythropoiesis and is secreted mainly by the kidney upon hypoxic or anemic stress. The paucity of EPO production in renal EPO-producing cells (REPs) causes renal anemia, one of the most common complications of chronic nephropathies. Although mitochondrial dysfunction is commonly observed in several renal and hematopoietic disorders, the mechanism by which mitochondrial quality control impacts renal anemia remains elusive. In this study, we showed that FUNDC1, a mitophagy receptor, plays a critical role in EPO-driven erythropoiesis induced by stresses. Mechanistically, EPO production is impaired in REPs in Fundc1-/- mice upon stresses, and the impairment is caused by the accumulation of damaged mitochondria, which consequently leads to the elevation of the reactive oxygen species (ROS) level and triggers inflammatory responses by up-regulating proinflammatory cytokines. These inflammatory factors promote the myofibroblastic transformation of REPs, resulting in the reduction of EPO production. We therefore provide a link between aberrant mitophagy and deficient EPO generation in renal anemia. Our results also suggest that the mitochondrial quality control safeguards REPs under stresses, which may serve as a potential therapeutic strategy for the treatment of renal anemia.

scholarly journals Multitiered and Cooperative Surveillance of Mitochondrial Phosphatidylserine Decarboxylase 1

2017 ◽  
Vol 37 (17) ◽  
Author(s):  
Oluwaseun B. Ogunbona ◽  
Ouma Onguka ◽  
Elizabeth Calzada ◽  
Steven M. Claypool
Keyword(s):  
Quality Control ◽  
Heat Exposure ◽  
Mitochondrial Pathway ◽  
Temperature Sensitive ◽  
Intermembrane Space ◽  
Control Mechanisms ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Quality Control ◽  
Inner Membrane ◽  
Α Subunit

ABSTRACT Phosphatidylserine decarboxylase 1 (Psd1p), an ancient enzyme that converts phosphatidylserine to phosphatidylethanolamine in the inner mitochondrial membrane, must undergo an autocatalytic self-processing event to gain activity. Autocatalysis severs the protein into a large membrane-anchored β subunit that noncovalently associates with the small α subunit on the intermembrane space side of the inner membrane. Here, we determined that a temperature sensitive (ts) PSD1 allele is autocatalytically impaired and that its fidelity is closely monitored throughout its life cycle by multiple mitochondrial quality control proteases. Interestingly, the proteases involved in resolving misfolded Psd1ts vary depending on its autocatalytic status. Specifically, the degradation of a Psd1ts precursor unable to undergo autocatalysis requires the unprecedented cooperative and sequential actions of two inner membrane proteases, Oma1p and Yme1p. In contrast, upon heat exposure postautocatalysis, Psd1ts β subunits accumulate in protein aggregates that are resolved by Yme1p acting alone, while the released α subunit is degraded in parallel by an unidentified protease. Importantly, the stability of endogenous Psd1p is also influenced by Yme1p. We conclude that Psd1p, the key enzyme required for the mitochondrial pathway of phosphatidylethanolamine production, is closely monitored at several levels and by multiple mitochondrial quality control mechanisms present in the intermembrane space.

The human disease gene CLEC16A encodes an intrinsically disordered protein region required for mitochondrial quality control

2021 ◽  
Author(s):  
Morgan A. Gingerich ◽  
Xueying Liu ◽  
Biaoxin Chai ◽  
Gemma L. Pearson ◽  
Michael P. Vincent ◽  
...  
Keyword(s):  
Quality Control ◽  
Human Disease ◽  
Intrinsically Disordered Protein ◽  
Mitochondrial Quality Control ◽  
Intrinsically Disordered ◽  
Disordered Protein ◽  
Functional Regions ◽  
C Terminus ◽  
Intrinsically Disordered Protein Region

CLEC16A regulates mitochondrial health through mitophagy and is associated with over 20 human diseases. While CLEC16A has ubiquitin ligase activity, the key structural and functional regions of CLEC16A, and their relevance for human disease, remain unknown. Here, we report that a disease-associated CLEC16A variant lacks a C-terminal intrinsically disordered protein region (IDPR) that is critical for mitochondrial quality control. Using carbon detect NMR, we find that the CLEC16A C terminus lacks secondary structure, validating the presence of an IDPR. Loss of the CLEC16A C-terminal IDPR in vivo impairs pancreatic β-cell mitophagy, mitochondrial function, and glucose-stimulated insulin secretion, ultimately causing glucose intolerance. Deletion of the CLEC16A C-terminal IDPR increases its self-ubiquitination and destabilizes CLEC16A, thus impairing formation of a critical CLEC16A-dependent mitophagy complex. Importantly, CLEC16A stability is dependent on proline bias within the C-terminal IDPR, but not amino acid sequence order or charge. Together, we clarify how an IDPR in CLEC16A prevents diabetes, thus implicating the disruption of IDPRs as novel pathological contributors to diabetes and other CLEC16A-associated diseases.

scholarly journals Mitochondria Homeostasis and Oxidant/Antioxidant Balance in Skeletal Muscle—Do Myokines Play a Role?

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 179
Author(s):  
Brian Pak Shing Pang ◽  
Wing Suen Chan ◽  
Chi Bun Chan
Keyword(s):  
Skeletal Muscle ◽  
Quality Control ◽  
Control System ◽  
Energy Content ◽  
Mitochondrial Dynamics ◽  
Critical Role ◽  
Oxidative Capacity ◽  
Quality Control System ◽  
Mitochondrial Quality Control ◽  
Tissue Mass

Mitochondria are the cellular powerhouses that generate adenosine triphosphate (ATP) to substantiate various biochemical activities. Instead of being a static intracellular structure, they are dynamic organelles that perform constant structural and functional remodeling in response to different metabolic stresses. In situations that require a high ATP supply, new mitochondria are assembled (mitochondrial biogenesis) or formed by fusing the existing mitochondria (mitochondrial fusion) to maximize the oxidative capacity. On the other hand, nutrient overload may produce detrimental metabolites such as reactive oxidative species (ROS) that wreck the organelle, leading to the split of damaged mitochondria (mitofission) for clearance (mitophagy). These vital processes are tightly regulated by a sophisticated quality control system involving energy sensing, intracellular membrane interaction, autophagy, and proteasomal degradation to optimize the number of healthy mitochondria. The effective mitochondrial surveillance is particularly important to skeletal muscle fitness because of its large tissue mass as well as its high metabolic activities for supporting the intensive myofiber contractility. Indeed, the failure of the mitochondrial quality control system in skeletal muscle is associated with diseases such as insulin resistance, aging, and muscle wasting. While the mitochondrial dynamics in cells are believed to be intrinsically controlled by the energy content and nutrient availability, other upstream regulators such as hormonal signals from distal organs or factors generated by the muscle itself may also play a critical role. It is now clear that skeletal muscle actively participates in systemic energy homeostasis via producing hundreds of myokines. Acting either as autocrine/paracrine or circulating hormones to crosstalk with other organs, these secretory myokines regulate a large number of physiological activities including insulin sensitivity, fuel utilization, cell differentiation, and appetite behavior. In this article, we will review the mechanism of myokines in mitochondrial quality control and ROS balance, and discuss their translational potential.

scholarly journals Barth syndrome cellular models have dysregulated respiratory chain complex I and mitochondrial quality control due to abnormal cardiolipin

2021 ◽  
Author(s):  
Arianna Franca Anzmann ◽  
Olivia Sniezek ◽  
Alexandra Pado ◽  
Veronica F. Busa ◽  
Frederic M Vaz ◽  
...  
Keyword(s):  
Quality Control ◽  
Respiratory Chain ◽  
Complex I ◽  
Chain Complex ◽  
Mitochondrial Respiratory Chain ◽  
Barth Syndrome ◽  
Hek293 Cells ◽  
Respiratory Chain Complex ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Quality Control

Barth syndrome (BTHS) is an X-linked genetic condition caused by defects in TAZ, which encodes a transacylase involved in the remodeling of the inner mitochondrial membrane phospholipid, cardiolipin (CL). As such, CL has been implicated in numerous mitochondrial functions, and the role of defective CL in the clinical pathology of BTHS is under intense investigation. We used untargeted proteomics, shotgun lipidomics, gene expression analysis, and targeted metabolomics to identify novel areas of mitochondrial dysfunction in a new model of TAZ deficiency in HEK293 cells. Functional annotation analysis of proteomics data revealed abnormal regulation of mitochondrial respiratory chain complex I (CI), driven by the reduced abundance of 6 CI associated proteins in TAZ-deficient HEK293 cells: MT-ND3, NDUFA5, NDUFAB1, NDUFB2, NDUFB4, and NDUFAF1. This resulted in reduced assembly and function of CI in TAZ-deficient HEK293 cells as well as BTHS patient derived lymphoblast cells. We also identified increased abundance of PARL, a rhomboid protein involved in the regulation of mitophagy and apoptosis, and abnormal downstream processing of PGAM5, another mediator of mitochondrial quality control, in TAZ-deficient cells. Lastly, we modulated CL via the phospholipase inhibitor bromoenol lactone and the CL targeted SS-peptide, SS-31, and showed that each is able to remediate abnormalities in CI abundance as well as PGAM5 processing. Thus, mitochondrial respiratory chain CI and PARL/PGAM5 regulated mitochondrial quality control, both of whose functions localize to the inner mitochondrial membrane, are dysregulated due to TAZ deficiency and are partially remediated via modulation of CL.

scholarly journals Culling sick mitochondria from the herd

2010 ◽  
Vol 191 (7) ◽  
pp. 1225-1227 ◽  
Author(s):  
Leo J. Pallanck
Keyword(s):  
Quality Control ◽  
Endoplasmic Reticulum ◽  
Critical Role ◽  
Mitochondrial Fusion ◽  
Mitochondrial Quality Control ◽  
Endoplasmic Reticulum Associated Degradation ◽  
Cell Biol

The PINK1–Parkin pathway plays a critical role in mitochondrial quality control by selectively targeting damaged mitochondria for autophagy. In this issue, Tanaka et al. (2010. J. Cell Biol. doi: 10.1083/jcb.201007013) demonstrate that the AAA-type ATPase p97 acts downstream of PINK1 and Parkin to segregate fusion-incompetent mitochondria for turnover. p97 acts by targeting the mitochondrial fusion-promoting factor mitofusin for degradation through an endoplasmic reticulum–associated degradation (ERAD)-like mechanism.

scholarly journals Decreasing pdzd8-mediated mitochondrial-ER contacts in neurons improves fitness by increasing mitophagy

2020 ◽  
Author(s):  
Victoria L. Hewitt ◽  
Leonor Miller-Fleming ◽  
Simonetta Andreazza ◽  
Francesca Mattedi ◽  
Julien Prudent ◽  
...  
Keyword(s):  
Quality Control ◽  
Healthy Aging ◽  
Synapse Formation ◽  
Critical Role ◽  
Functional Characterization ◽  
Protective Effects ◽  
Mitochondrial Quality Control ◽  
Age Related ◽  
The Many

AbstractThe complex cellular architecture of neurons combined with their longevity makes maintaining a healthy mitochondrial network particularly important and challenging. One of the many roles of mitochondrial-ER contact sites (MERCs) is to mediate mitochondrial quality control through regulating mitochondrial turn over. Pdzd8 is a newly discovered MERC protein, the organismal functions of which have not yet been explored. Here we identify and provide the first functional characterization of the Drosophila melanogaster ortholog of Pdzd8. We find that reducing pdzd8-mediated MERCs in neurons slows age-associated decline in locomotor activity and increases lifespan in Drosophila. The protective effects of pdzd8 knockdown in neurons correlate with an increase in mitophagy, suggesting that increased mitochondrial turnover may support healthy aging of neurons. In contrast, increasing MERCs by expressing a constitutive, synthetic ER-mitochondria tether disrupts mitochondrial transport and synapse formation, accelerates age-related decline in locomotion and reduces lifespan. We also show that depletion of pdzd8 rescues the locomotor defects characterizing an Alzheimer’s disease (AD) fly model over-expressing Amyloidβ1–42 (Aβ42) and prolongs the survival of flies fed with mitochondrial toxins. Together, our results provide the first in vivo evidence that MERCs mediated by the tethering protein pdzd8 play a critical role in the regulation of mitochondrial quality control and neuronal homeostasis.

scholarly journals The Interplay among PINK1/PARKIN/Dj-1 Network during Mitochondrial Quality Control in Cancer Biology: Protein Interaction Analysis

Cells ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 154 ◽  
Author(s):  
Celia Salazar ◽  
Paula Ruiz-Hincapie ◽  
Lina Ruiz
Keyword(s):  
Quality Control ◽  
Protein Interactions ◽  
Cancer Biology ◽  
Mitochondrial Membrane ◽  
Interaction Analysis ◽  
Enrichment Analysis ◽  
Mitochondrial Morphology ◽  
Transcriptional Level ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Quality Control

PARKIN (E3 ubiquitin ligase PARK2), PINK1 (PTEN induced kinase 1) and DJ-1 (PARK7) are proteins involved in autosomal recessive parkinsonism, and carcinogenic processes. In damaged mitochondria, PINK1’s importing into the inner mitochondrial membrane is prevented, PARKIN presents a partial mitochondrial localization at the outer mitochondrial membrane and DJ-1 relocates to mitochondria when oxidative stress increases. Depletion of these proteins result in abnormal mitochondrial morphology. PINK1, PARKIN, and DJ-1 participate in mitochondrial remodeling and actively regulate mitochondrial quality control. In this review, we highlight that PARKIN, PINK1, and DJ-1 should be regarded as having an important role in Cancer Biology. The STRING database and Gene Ontology (GO) enrichment analysis were performed to consolidate knowledge of well-known protein interactions for PINK1, PARKIN, and DJ-1 and envisage new ones. The enrichment analysis of KEGG pathways showed that the PINK1/PARKIN/DJ-1 network resulted in Parkinson disease as the main feature, while the protein DJ-1 showed enrichment in prostate cancer and p53 signaling pathway. Some predicted transcription factors regulating PINK1, PARK2 (PARKIN) and PARK7 (DJ-1) gene expression are related to cell cycle control. We can therefore suggest that the interplay among PINK1/PARKIN/DJ-1 network during mitochondrial quality control in cancer biology may occur at the transcriptional level. Further analysis, like a systems biology approach, will be helpful in the understanding of PINK1/PARKIN/DJ-1 network.

Sign in / Sign up

Export Citation Format

Share Document