GRIM-19, a Cell Death Regulatory Protein, Is Essential for Assembly and Function of Mitochondrial Complex I

Abstract

Mitochondria play essential roles in cellular energy production via the oxidative phosphorylation system (OXPHOS) consisting of five multiprotein complexes and also in the initiation of apoptosis. NADH:ubiquinone oxidoreductase (complex I) is the largest complex that catalyzes the first step of electron transfer in the OXPHOS system. GRIM-19 was originally identified as a nuclear protein with apoptotic nature in interferon (IFN)-and all-trans-retinoic acid (RA)-induced tumor cells. To reveal its biological role, we generated mice deficient in GRIM-19 by gene targeting. Homologous deletion of GRIM-19 causes embryonic lethality at embryonic day 9.5. GRIM-19؊/؊ blastocysts show retarded growth in vitro and, strikingly, display abnormal mitochondrial structure, morphology, and cellular distribution. We reexamined the cellular localization of GRIM-19 in various cell types and found its primary localization in the mitochondria. Furthermore, GRIM-19 is detected in the native form of mitochondrial complex I. Finally, we show that elimination of GRIM-19 destroys the assembly and electron transfer activity of complex I and also influences the other complexes in the mitochondrial respiratory chain. Our result demonstrates that GRIM-19, a gene product with a specific role in IFN-RA-induced cell death, is a functional component of mitochondrial complex I and is essential for early embryonic development.

Coupling mitochondrial respiratory chain to cell death: an essential role of mitochondrial complex I in the interferon-β and retinoic acid-induced cancer cell death

“…Consistent with this finding, we further demonstrated that GRIM-19 is localized in the mitochondria, associates with mitochondrial complex I, and plays essential roles in the assembly and enzymatic activity of complex I. 14 Based on its primary function in mitochondria, GRIM-19 has been recently suggested to be re-named as NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 13 (NDUFA13) by HUGO Gene Nomenclature Committee (HGNC).…”

“…GRIM-19 was originally claimed as a nuclear protein, 10 but was later shown to be a mitochondrial protein. 11,12,14 In a recent review by Kalvakolanu, 34 it was proposed that GRIM-19 may initiate apoptosis, like cytochrome c and AIF, by translocation from the mitochondria to the nucleus upon IFN-b/RA stimulation. To test this hypothesis, we analyzed the cellular localization of GRIM-19, as well as other MRC subunit proteins, in the absence and presence of IFN-b/RA.…”

“…12,13 To reveal its physiological role, we generated GRIM-19-deficient mice by gene targeting. 14 Although the deletion of GRIM-19 causes embryonic lethality, isolated GRIM-19 À/À blastocysts displayed abnormal mitochondrial structure and morphology. Consistent with this finding, we further demonstrated that GRIM-19 is localized in the mitochondria, associates with mitochondrial complex I, and plays essential roles in the assembly and enzymatic activity of complex I.…”

Identification of alternatively spliced GRIM-19 mRNA in kidney cancer tissues

“…First-strand cDNA was synthesized from 3-5 mg of total RNA by oligo(dT) 15 primed reverse transcription with Expand Reverse Transcriptase (Roche Applied Science, Mannheim, Germany). The synthesized cDNA was subjected to PCR by using a pair of primers: 5¢-ATGCAAGAACCAAGGCGAGT-3¢ and 5¢-CAGAGCATTTCCGTCCCA-3¢ to amplify the GRIM-19-encoding fragment.…”

“…13 Subsequently, GRIM-19 was demonstrated to be a new subunit of the mitochondrial NAPDH:ubiquinone oxidoredutase (respiratory chain complex I) and is essential for the complex I assembly, activity and maintenance of mitochondrial membrane potential. [14][15][16][17] Disruption of mitochondrial transmembrane potential by GRIM-19 mutants enhances the cells' sensitivity to apoptotic stimuli. 17 Furthermore, GRIM-19 has also been shown to repress the activity of the Signal Transducer and Activator of Transcription 3 (Stat3) and inhibit v-Src-induced oncogenic transformation and metastatic behavior of cells.…”