ABSTRACT
ATAD3 (ATPase family AAA domain-containing protein 3) is a mitochondrial protein, which is essential for cell viability and organismal development. ATAD3 has been implicated in several important cellular processes such as apoptosis regulation, respiratory chain function and steroid hormone biosynthesis. Moreover, altered expression of ATAD3 has been associated with several types of cancer. However, the exact mechanisms underlying ATAD3 effects on cellular metabolism remain largely unclear. Here, we demonstrate that Caenorhabditis elegans ATAD-3 is involved in mitochondrial iron and heme homeostasis. Knockdown of atad-3 caused mitochondrial iron- and heme accumulation. This was paralleled by changes in the expression levels of several iron- and heme-regulatory genes as well as an increased heme uptake. In conclusion, our data indicate a regulatory role of C. elegans ATAD-3 in mitochondrial iron and heme metabolism.
Subject(s)
Caenorhabditis elegans Proteins/genetics , Caenorhabditis elegans/genetics , Heme/metabolism , Iron/metabolism , Mitochondria/genetics , Mitochondrial Proteins/genetics , Animals , Caenorhabditis elegans/drug effects , Caenorhabditis elegans/metabolism , Caenorhabditis elegans Proteins/antagonists & inhibitors , Caenorhabditis elegans Proteins/metabolism , Ferric Compounds/pharmacology , Gene Expression Regulation , Hemeproteins/genetics , Hemeproteins/metabolism , Hemin/metabolism , Homeostasis , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondrial Proteins/antagonists & inhibitors , Mitochondrial Proteins/metabolism , Oxidative Phosphorylation/drug effects , Protein Isoforms/genetics , Protein Isoforms/metabolism , Quaternary Ammonium Compounds/pharmacology , RNA, Small Interfering/genetics , RNA, Small Interfering/metabolism , Signal TransductionABSTRACT
The biogenesis of mitochondrial NADH:ubiquinone oxidoreductase (complex I) requires several assembly chaperones. These so-called complex I assembly factors have emerged as a new class of human disease genes. Here, we identified putative assembly factor homologues in Caenorhabditis elegans. We demonstrate that two candidates (C50B8.3/NUAF-1, homologue of NDUFAF1 and R07H5.3/NUAF-3, homologue of NDUFAF3) clearly affect complex I function. Assembly factor deficient worms were shorter, showed a diminished brood size and displayed reduced fat content. Our results suggest that mitochondrial complex I biogenesis is evolutionarily conserved. Moreover, Caenorhabditis elegans appears to be a promising model organism to study assembly factor related human diseases.
Subject(s)
Caenorhabditis elegans Proteins/metabolism , Caenorhabditis elegans/metabolism , Electron Transport Complex I/metabolism , Mitochondria/metabolism , Mitochondrial Proteins/metabolism , Sequence Homology, Amino Acid , Animals , Caenorhabditis elegans/genetics , Caenorhabditis elegans Proteins/genetics , Electron Transport Complex I/genetics , Humans , Mitochondrial Proteins/genetics , NADH Dehydrogenase/genetics , NADH Dehydrogenase/metabolism , Organelle BiogenesisABSTRACT
Blue native polyacrylamide gel electrophoresis (BN-PAGE) is an essential tool for investigating mitochondrial respiratory chain complexes. However, with current BN-PAGE protocols for Caenorhabditis elegans (C. elegans), large worm amounts and high quantities of mitochondrial protein are required to yield clear results. Here, we present an efficient approach to isolate mitochondrial complex I (NADH:ubiquinone oxidoreductase) from C. elegans, grown on agar plates. We demonstrate that considerably lower amounts of mitochondrial protein are sufficient to isolate complex I and to display clear in-gel activity results. Moreover, we present the first complex I assembly profile for C. elegans, obtained by two-dimensional BN/SDS-PAGE.
