PINK1 accumulation at the outer mitochondrial membrane (OMM) is a key event required to signal depolarized mitochondria to the autophagy machinery. How this early step is, in turn, modulated by autophagy proteins remains less characterized. Here, we show that, upon mitochondrial depolarization, the proautophagic protein AMBRA1 is recruited to the OMM and interacts with PINK1 and ATAD3A, a transmembrane protein that mediates mitochondrial import and degradation of PINK1. Downregulation of AMBRA1 expression results in reduced levels of PINK1 due to its enhanced degradation by the mitochondrial protease LONP1, which leads to a decrease in PINK1-mediated ubiquitin phosphorylation and mitochondrial PRKN/PARKIN recruitment. Notably, ATAD3A silencing rescues defective PINK1 accumulation in AMBRA1-deficient cells upon mitochondrial damage. Overall, our findings underline an upstream contribution of AMBRA1 in the control of PINK1-PRKN mitophagy by interacting with ATAD3A and promoting PINK1 stability. This novel regulatory element may account for changes of PINK1 levels in neuropathological conditions. ACTB/β-actin: actin beta; AMBRA1: autophagy and beclin 1 regulator 1; ATAD3A: ATPase family AAA domain containing 3A; BCL2L1/BCL-xL: BCL2 like 1; CCCP: carbonyl cyanide m-chlorophenyl hydrazone; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; OMA1: OMA1 zinc metallopeptidase; OMM: outer mitochondrial membrane; PARL: presenilin associated rhomboid like; PARP: poly(ADP-ribose) polymerase; PD: Parkinson disease; PINK1: PTEN induced kinase 1; PRKN/PARKIN: parkin RBR E3 ubiquitin protein ligase; SDHA: succinate dehydrogenase complex flavoprotein subunit A; TOMM70: translocase of outer mitochondrial membrane 70.
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http://dx.doi.org/10.1080/15548627.2021.1997052 | DOI Listing |
J Cell Sci
January 2025
Zellbiologie, Universität Bayreuth, 95440 Bayreuth, Germany.
Budding yeast cells multiply by asymmetric cell division. During this process, the cell organelles are transported by myosin motors along the actin cytoskeleton into the growing bud, while at the same time some organelles must be retained in the mother cell. The ordered partitioning of organelles depends on highly regulated binding of motor proteins to cargo membranes.
View Article and Find Full Text PDFNat Cell Biol
January 2025
Biochemistry Section, Surgical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
Mitochondrial protein import through the outer and inner membranes is key to mitochondrial biogenesis. Recent studies have explored how cells respond when import is impaired by a variety of different insults. Here, we developed a mammalian import blocking system using dihydrofolate reductase fused to the N terminus of the inner membrane protein MIC60.
View Article and Find Full Text PDFJ Endocrinol
January 2025
W Miller, Department of Pediatrics, Center for Reproductive Sciences, and Institute for Human Genetics University of California, San Francisco, United Kingdom of Great Britain and Northern Ireland.
Current understanding of the biology, biochemistry and genetics of the steroidogenic acute regulatory protein (StAR) and its deficiency state (congenital lipoid adrenal hyperplasia, lipoid CAH) involves the complex interplay of four areas of study: the acute regulation of steroidogenesis, clinical phenomena in lipoid CAH, the enzymatic conversion of cholesterol to pregnenolone in steroidogenic mitochondria, and the cell biology of StAR. This review traces the origins of these areas of study, describes how they have been woven into an increasingly coherent fabric, and tries to explore some remaining loose ends in this ongoing field of endocrine research. Abundant research from multiple laboratories establishes that StAR is required for the rapid, abundant steroidal responses of the adrenals and gonads, but all steroidogenic cells, especially the placenta, have StAR-independent steroidogenesis, whose basis remains under investigation.
View Article and Find Full Text PDFPoult Sci
December 2024
MOA Key Laboratory of Animal Virology, College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China; Department of Veterinary Medicine, College of Animal Sciences, Zhejiang University, Hangzhou 310058, PR China. Electronic address:
FEBS Lett
January 2025
Institute of Pharmaceutical Science, King's College London, UK.
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