hNOA1 Interacts with Complex I and DAP3 and Regulates Mitochondrial Respiration and Apoptosis

Abstract

Mitochondria are dynamic organelles that play key roles in metabolism, energy production, and apoptosis. Coordination of these processes is essential to maintain normal cellular functions. Here we characterized hNOA1, the human homologue of AtNOA1 (Arabidopsis thaliana nitric oxide-associated protein 1), a large mitochondrial GTPase. By immunofluorescence, immunoelectron microscopy, and mitochondrial subfractionation, endogenous hNOA1 is localized within mitochondria where it is peripherally associated with the inner mitochondrial membrane facing the mitochondrial matrix. Overexpression and knockdown of hNOA1 led to changes in mitochondrial shape implying effects on mitochondrial dynamics. To identify the interaction partners of hNOA1 and to further understand its cellular functions, we performed immunoprecipitation-mass spectrometry analysis of endogenous hNOA1 from enriched mitochondrial fractions and found that hNOA1 interacts with both Complex I of the electron transport chain and DAP3 (death-associated protein 3), a positive regulator of apoptosis. Knockdown of hNOA1 reduces mitochondrial O2 consumption ∼20% in a Complex I-dependent manner, supporting a functional link between hNOA1 and Complex I. Moreover, knockdown of hNOA1 renders cells more resistant to apoptotic stimuli such as γ-interferon and staurosporine, supporting a role for hNOA1 in regulating apoptosis. Thus, based on its interactions with both Complex I and DAP3, hNOA1 may play a role in mitochondrial respiration and apoptosis. Mitochondria are dynamic organelles that play key roles in metabolism, energy production, and apoptosis. Coordination of these processes is essential to maintain normal cellular functions. Here we characterized hNOA1, the human homologue of AtNOA1 (Arabidopsis thaliana nitric oxide-associated protein 1), a large mitochondrial GTPase. By immunofluorescence, immunoelectron microscopy, and mitochondrial subfractionation, endogenous hNOA1 is localized within mitochondria where it is peripherally associated with the inner mitochondrial membrane facing the mitochondrial matrix. Overexpression and knockdown of hNOA1 led to changes in mitochondrial shape implying effects on mitochondrial dynamics. To identify the interaction partners of hNOA1 and to further understand its cellular functions, we performed immunoprecipitation-mass spectrometry analysis of endogenous hNOA1 from enriched mitochondrial fractions and found that hNOA1 interacts with both Complex I of the electron transport chain and DAP3 (death-associated protein 3), a positive regulator of apoptosis. Knockdown of hNOA1 reduces mitochondrial O2 consumption ∼20% in a Complex I-dependent manner, supporting a functional link between hNOA1 and Complex I. Moreover, knockdown of hNOA1 renders cells more resistant to apoptotic stimuli such as γ-interferon and staurosporine, supporting a role for hNOA1 in regulating apoptosis. Thus, based on its interactions with both Complex I and DAP3, hNOA1 may play a role in mitochondrial respiration and apoptosis. Emerging evidence indicates that mitochondrial metabolism, apoptosis, and dynamics (fission and fusion) are closely intertwined. Apoptosis and changes in metabolism are associated with morphological changes in mitochondria (1Bossy-Wetzel E. Barsoum M.J. Godzik A. Schwarzenbacher R. Lipton S.A. Curr. Opin. Cell Biol. 2003; 15: 706-716Crossref PubMed Scopus (370) Google Scholar, 2McBride H.M. Neuspiel M. Wasiak S. Curr. Biol. 2006; 16: R551-R560Abstract Full Text Full Text PDF PubMed Scopus (1413) Google Scholar). Conversely, when mitochondrial morphology is altered either by mutations or altered expression of mitochondrial fission or fusion proteins such as the dynamin like large G proteins Drp1 and Opa1, the cell's susceptibility to apoptotic agents (3Chan D.C. Annu. Rev. Cell Dev. Biol. 2006; 22: 79-99Crossref PubMed Scopus (749) Google Scholar) or ability to generate ATP (4Olichon A. Baricault L. Gas N. Guillou E. Valette A. Belenguer P. Lenaers G. J. Biol. Chem. 2003; 278: 7743-7746Abstract Full Text Full Text PDF PubMed Scopus (901) Google Scholar, 5Chen H. Chomyn A. Chan D.C. J. Biol. Chem. 2005; 280: 26185-26192Abstract Full Text Full Text PDF PubMed Scopus (1026) Google Scholar) is altered. Apoptosis is controlled by a diverse range of cell signals, which may originate either extracellularly (extrinsic inducers) or intracellularly (intrinsic inducers), and mitochondria play central roles in both pathways (6Jin Z. El-Deiry W.S. Cancer Biol. Ther. 2005; 4: 139-163Crossref PubMed Scopus (996) Google Scholar). The apoptotic pathways involve a growing list of mitochondria-associated proteins, such as Bad, cytochrome c, Smac, AIF, Bcl-2, and others, most of which are located either on the outer mitochondrial membrane (OMM) 3The abbreviations used are: OMM, outer mitochondrial membrane; PFA, paraformaldehyde; IMS, intermembrane space; AtNOA1, A. thaliana nitric oxide-associated protein 1; GST, glutathione S-transferase; siRNA, small interference RNA; RNAi, RNA interference; PBS, phosphate-buffered saline; BSA, bovine serum albumin; DMEM, Dulbecco's modified Eagle's medium; TUNEL, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling; IP-MS, immunoprecipitation-mass spectrometry; NOS, nitric-oxide synthase. or in the intermembrane space (IMS) (7Kim R. Emi M. Tanabe K. Cancer Chemother. Pharmacol. 2006; 57: 545-553Crossref PubMed Scopus (258) Google Scholar). Recently, proteins of the mitochondrial matrix such as DAP3, have also been shown to be involved in apoptosis (8Berger T. Brigl M. Herrmann J.M. Vielhauer V. Luckow B. Schlondorff D. Kretzler M. J. Cell Sci. 2000; 113: 3603-3612Crossref PubMed Google Scholar). DAP3 has been reported to be involved in both γ-interferon- (9Kim H.R. Chae H.J. Thomas M. Miyazaki T. Monosov A. Monosov E. Krajewska M. Krajewski S. Reed J.C. FASEB J. 2007; 21: 188-196Crossref PubMed Scopus (45) Google Scholar) and tumor necrosis factor-α-induced (10Kissil J.L. Deiss L.P. Bayewitch M. Raveh T. Khaspekov G. Kimchi A. J. Biol. Chem. 1995; 270: 27932-27936Abstract Full Text Full Text PDF PubMed Scopus (110) Google Scholar) apoptosis as well as staurosporine-induced mitochondrial fragmentation (11Mukamel Z. Kimchi A. J. Biol. Chem. 2004; 279: 36732-36738Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar), but the detailed mechanisms involved remain to be elucidated. Besides their role in apoptosis, much more is known about the functions of mitochondria in respiration and generation of ATP. The electron transport chain in the inner mitochondrial membrane (IMM) contains four major enzyme complexes (Complexes I, II, III, and IV) that are involved in transferring electrons from NADH (Complex I-linked) or FADH2 (Complex II-linked) to O2 and in pumping protons out of the matrix to create an electrochemical proton gradient, which is harnessed by ATP synthase to make ATP (12Alberts B. Bray D. Lewis J. Raff M. Roberts K. Walter P. Mol. Biol. Cell. 2008; 5: 827-840Google Scholar). Despite the accumulating evidence showing intercommunication between mitochondrial metabolism, apoptosis, and dynamics, how these processes are coordinated remains to be elucidated. In this study we characterize hNOA1, the human homologue of Arabidopsis thaliana nitric oxide-associated protein, 1 (AtNOA1) (13Crawford N.M. Galli M. Tischner R. Heimer Y.M. Okamoto M. Mack A. Trends Plant Sci. 2006; 11: 526-527Abstract Full Text Full Text PDF Scopus (208) Google Scholar). hNOA1 is a large G protein closely related to dynamin that is associated with the IMM. Perturbation of hNOA1 affects mitochondrial morphology, Complex I-linked O2 consumption, and the cell's susceptibility to apoptotic stimuli, possibly through interactions with proteins such as Complex I and DAP3. Vectors—Human hNOA1 (NP_115689) and human DAP3 (NP_004623) in pOTB7 cloning vector were purchased from Open Biosystems (Huntsville, AL). hNOA1 or its truncation mutants were subcloned by PCR using pOTB7-hNOA1 as a template into pET28a(+) (Novagen), pGEX-KG (GE), and pcDNA3.1/zeo(+) (Invitrogen) vectors. DAP3 was subcloned by PCR into pcDNA3.1/zeo(+) and pET28a(+) vectors. Sequences were verified by sequencing (DNA Sequencing Shared Resource, University of California at San Diego, Moores Cancer Center). Antibodies—Antiserum against human hNOA1 was raised in rabbits against the purified His6-tagged C terminus (amino acids 67-698) of human hNOA1 and affinity purified on GST-tagged hNOA1 coupled to CNBr-Sepharose as P. H. R. J.M. M. H. T. L. J. Cell Biol. PubMed Scopus Google Scholar). was with and with 1 were from the against DAP3, and cytochrome ATP synthase and Complex I I and and were purchased from San and RNA small RNA by were used for knockdown of were based on human RNA were used as cells well were in cells were with of and of (Invitrogen) cells were either in for or on the with for by of for were into small and with a in were in at for 1 with were by at for M. T. T. Mol. Biol. Cell. 2003; PubMed Scopus Google Scholar). were by from were by by with M. T. T. Mol. Biol. Cell. 2003; PubMed Scopus Google Scholar, H. I. T. L. J. Biol. Chem. 2005; 280: Full Text Full Text PDF PubMed Scopus Google Scholar). were by or and to were with in for 1 at and with affinity purified or for at or at by with in or in for 1 and by (amino acids 67-698) and were by PCR and subcloned into pET28a(+) vector and fusion proteins were in purified on and with to the The protein for protein was by of the fusion proteins and of were in of The was by of and at for The was on and in a at for with from the were by and the was with and by on E. J.M. Mol. Biol. Cell. PubMed Scopus Google Scholar, T. T. K. K. S. N. PubMed Scopus Google Scholar). Cell and and cells were in Dulbecco's modified Eagle's bovine serum and and cells were using to the or cells were in in for with for and with in for 1 at by for 1 were using a with a H. I. T. L. J. Biol. Chem. 2005; 280: Full Text Full Text PDF PubMed Scopus Google Scholar). were as using San were in in in in and in were at on a with an using a with a of and and and were and with for at by or to for 1 were in in on were and using a electron with a B. P. T. A. Mol. Biol. Cell. 2004; 15: PubMed Scopus Google Scholar). of were purified as PubMed Scopus Google Scholar) with was and with of a in of with with and The was at to and The was and at for to the mitochondrial which was on of a of and by at in an for 1 The purified mitochondrial was from the and at for and in a small of of Mitochondria from of mitochondria from cells was to that for mitochondria with cell from of cells were with and and in of the were with of a The was by and at to a mitochondrial The was with and with and in of was by and the fractions were on further of mitochondria from cells was in of for on to mitochondria and the OMM, the proteins from the P. Mol. Cell. 2005; Full Text Full Text PDF PubMed Scopus Google Scholar). The mitochondria were at to the contains the and the which was in the as the of and were by by with c, and the S.A. P. Sci. S. A. 2007; PubMed Scopus Google Scholar), was to mitochondria for at was by and the were for and by the or S.A. P. Sci. S. A. 2007; PubMed Scopus Google Scholar), a mitochondrial as was with either or for on were at The and were and the was in the of was to the were for and the proteins were by for hNOA1 cells hNOA1 were using the to the hNOA1 were in the or of 1 for to the expression of The cells were by with and mitochondria were with In were and the cells with mitochondria normal mitochondria were analysis was performed by and 1 of mitochondria from cells was in in for at the was with or for at by with of protein for an 1 at The were with and in and complexes were by B. P. T. A. Mol. Biol. Cell. 2004; 15: PubMed Scopus Google Scholar), with and the in the hNOA1 were for protein by spectrometry as H. J. Biol. Chem. 2004; 279: Full Text Full Text PDF PubMed Scopus Google Scholar, S. M. R. N. H. Mol. Biol. Cell. 2008; PubMed Scopus Google Scholar). cell were as in in and 1 Cell were with at by with protein or San Diego, for an 1 at were with and in and complexes were by and B. P. T. A. Mol. Biol. Cell. 2004; 15: PubMed Scopus Google Scholar). In or fusion proteins were purified on as cell were from a with in PBS, in of DAP3 were using the in the of was in cells and purified on affinity to the fusion protein was with or fusion proteins on were with cell in DAP3 or of purified in with in the of for at with the proteins were with and by the in DAP3 the was with and by on B. P. T. A. Mol. Biol. Cell. 2004; 15: PubMed Scopus Google Scholar). the cell and proteins were to by with and DAP3 of O2 on cells were with or for and and in of respiration in cells were in of 1 to the and with in the of and (Complex I-linked) or (Complex II-linked) in the of as of of electron through the electron transport chain were by with the G. E. G. Sci. S. A. PubMed Scopus Google Scholar). Cell cells well were in cells were with or with the cell was to with of γ-interferon for an were in 1 of DMEM, and using a cell In Cell cells with or for were with for were in for and was out using the In Cell by of hNOA1 a the human homologue of A. thaliana AtNOA1, is acids with a of hNOA1 contains a mitochondrial a and a hNOA1 is through from to within the T. T. K. K. S. N. PubMed Scopus Google Scholar). The Arabidopsis homologue of hNOA1 was as a mitochondrial and based on its to Okamoto M. N.M. 2003; PubMed Scopus Google Scholar, S. E. A. J. PubMed Scopus Google Scholar). the Arabidopsis was shown to be in it has been the protein or its purified from are to in T. A. M. I. S. M. P. J. Trends Plant Sci. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar, M. J. Biol. Chem. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar). it was that be to AtNOA1 for associated protein in A. thaliana T. M. N. S. R. I. M. M. P. P. M. S. 2006; PubMed Scopus Google Scholar). To the of hNOA1, we an against hNOA1 and performed on shown in we found that hNOA1 is in with expression in and expression in and and expression in and In a was in To hNOA1 is a protein, we performed an and found that both and as a positive the that hNOA1 is a hNOA1 in homologue of hNOA1 was shown to be localized in mitochondria when in cells T. M. N. S. R. I. M. M. P. P. M. S. 2006; PubMed Scopus Google Scholar). To the of endogenous hNOA1, we used and performed for hNOA1 and cytochrome c, a mitochondrial a B. Chan H. Mol. Biol. Cell. PubMed Scopus Google Scholar), and a S. M. G. N. R. D. J. K. E. P. Mol. Biol. Cell. 2004; 15: PubMed Scopus Google Scholar). found that for endogenous hNOA1 with cytochrome but with or the mitochondrial of hNOA1 by with mitochondrial synthase and Complex in and cells To the mitochondrial of hNOA1 at we out of endogenous hNOA1 using on of By electron microscopy, were found mitochondria where were closely associated with the mitochondrial but or were on the the of hNOA1 in mitochondria and its with the IMS, or mitochondrial but the hNOA1 in of the of hNOA1 in we mitochondrial fractions from by by The of mitochondria was by of ATP synthase and of and hNOA1 as well as ATP synthase were found to be enriched to in the purified mitochondrial with fractions by the by immunofluorescence, immunoelectron microscopy, and cell that endogenous hNOA1 is a mitochondrial hNOA1 on the of the the mitochondrial in which hNOA1 is we out mitochondrial fractions from cells by were in which the of the found that a of the cytochrome is both in the and on the facing the J.M. S. A. J. J.M. Cell Biol. PubMed Scopus Google Scholar, 1995; PubMed Scopus Google was into the by this hNOA1, with DAP3 on the matrix of the (8Berger T. Brigl M. Herrmann J.M. Vielhauer V. Luckow B. Schlondorff D. Kretzler M. J. Cell Sci. 2000; 113: 3603-3612Crossref PubMed Google and membrane protein associated with the facing the M. T. N. H. 2003; PubMed Scopus Google in the To further the of hNOA1, we out on found as on the facing the was when was to the hNOA1 and DAP3 on the facing the were from that hNOA1 is associated either with the inner of the facing the matrix or the mitochondrial matrix. To which is the we performed or on a mitochondrial and found that hNOA1, Opa1, and DAP3 were by but by was by both and P. Mol. Cell. 2005; Full Text Full Text PDF PubMed Scopus Google Scholar). The membrane protein I 1), in the or as these we that hNOA1 is a membrane protein that is to the IMM. is with the that it a based on these with the from we that hNOA1 is peripherally to the facing the matrix. Overexpression or of hNOA1 further the role of hNOA1 in we cells found expression of hNOA1 with mitochondria small and in of the cells in cells mitochondria were that of the cells small mitochondria of the cells cytochrome into the was when hNOA1 was by of By hNOA1 expression was in cells with with in the of we the effects of hNOA1 on mitochondrial of hNOA1 into cells led to a of in the of hNOA1 expression of the mitochondria in hNOA1 cells and more mitochondria in cells analysis changes in the of the mitochondria in the of the and the of the mitochondrial matrix when hNOA1 was of the mitochondria a matrix with and more in of hNOA1 through identify the partners of hNOA1 and into its mitochondrial functions, we out with or on enriched mitochondrial fractions from of that the four protein that were in with By spectrometry analysis the was as of both hNOA1 and the of Complex I. Complex I is the of the electron transport chain and the with facing the matrix G. R. A. 2006; PubMed Scopus Google Scholar). The at were as DAP3 known as and protein, both of which are localized to the matrix of the (8Berger T. Brigl M. Herrmann J.M. Vielhauer V. Luckow B. Schlondorff D. Kretzler M. J. Cell Sci. 2000; 113: 3603-3612Crossref PubMed Google Scholar, T. M. T. T. A. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). The at was as hNOA1 with Complex I and O2 in a Complex I-dependent the interaction between hNOA1 and Complex I, we performed with by with that the and of Complex I. hNOA1 was to the and of Complex I, but of Complex were to the between hNOA1 and the of Complex I in to the of of also the interaction between hNOA1 and the of Complex I in an in but was to the of Complex I from cell Complex I is the of the electron transport with Complex II, electrons from NADH or and the electron transport ATP is by ATP O2 is to with protons and electrons to Annu. Rev. PubMed Google Scholar). To the functions of the interaction between hNOA1 and Complex I, we endogenous hNOA1 by and O2 consumption in cells and or were to the cells as to the Complex or O2 consumption, G. E. G. Sci. S. A. PubMed Scopus Google Scholar). O2 consumption were by with the mitochondrial with a G. E. G. Sci. S. A. PubMed Scopus Google Scholar). found that when and were used as the of O2 consumption was ∼20% in cells in which hNOA1 was with in O2 consumption was between and cells when cells were or with the Complex that hNOA1 the of Complex I, but or respiration in cells are M. J. Z. Z. 2003; Google Scholar), by at the electron transport hNOA1 with DAP3 and the to Complex I, we also DAP3 as a hNOA1 protein from analysis the interaction between hNOA1 and DAP3 by and in which we found that hNOA1 was to endogenous DAP3 and but was to DAP3 from cell To hNOA1 is to with DAP3 we performed with purified or and in DAP3 or purified His6-tagged DAP3. found that was to both and these that hNOA1 is to with DAP3. DAP3 was as a positive regulator for apoptosis, of DAP3 by RNA cells from cell (10Kissil J.L. Deiss L.P. Bayewitch M. Raveh T. Khaspekov G. Kimchi A. J. Biol. Chem. 1995; 270: 27932-27936Abstract Full Text Full Text PDF PubMed Scopus (110) Google Scholar). To knockdown of hNOA1 has a we out a cell in the of found that as cells in the of γ-interferon and more with cells of hNOA1 cells from apoptosis. hNOA1 Knockdown from was also reported to be involved in staurosporine-induced mitochondrial fragmentation (11Mukamel Z. Kimchi A. J. Biol. Chem. 2004; 279: 36732-36738Abstract Full Text Full Text PDF PubMed Scopus (62) Google Scholar), which to apoptosis, and it was also found that of the homologue of hNOA1, to apoptosis in human cells and human cells A. Z. R. P. 2008; PubMed Scopus Google Scholar, A. Z. P. Sci. 2008; PubMed Scopus Google Scholar). To hNOA1 affects staurosporine-induced apoptosis, cells with or hNOA1 were with by of in cell by found that cells with hNOA1 C and with and that of the cells with of Besides we also cytochrome a of staurosporine-induced apoptosis. of cytochrome was by in either or hNOA1 By of the cells cytochrome into the of hNOA1 cells cytochrome we that mitochondria small and in cells as reported by M. Mol. Biol. Cell. 2004; 15: PubMed Scopus Google Scholar). when hNOA1 was by this morphological was with that in the mitochondria small and cytochrome and that of hNOA1 cells from staurosporine-induced apoptosis. In this study we localized endogenous hNOA1 by immunoelectron and mitochondrial subfractionation, its in and that it is peripherally associated with the facing the matrix. also partners of hNOA1 through hNOA1 was found to with both Complex I of the electron transport chain and DAP3, a protein involved in apoptosis. of hNOA1 led to a in mitochondrial O2 consumption in a Complex I-dependent and cells to γ-interferon and staurosporine-induced apoptosis, a functional link between hNOA1, Complex I, and DAP3. hNOA1 a role in regulating both mitochondrial respiration and apoptosis. The Arabidopsis homologue of hNOA1 was as a mitochondrial nitric-oxide synthase Okamoto M. N.M. 2003; PubMed Scopus Google Scholar), but the fusion protein or its were found to have T. A. M. I. S. M. P. J. Trends Plant Sci. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar). on the that the AtNOA1 Okamoto M. N.M. 2003; PubMed Scopus Google Scholar), it is that AtNOA1 with proteins to was that of the be a of the mitochondrial electron transport T. M. N. S. R. I. M. M. P. P. M. S. 2006; PubMed Scopus Google Scholar). of Complex I of the electron transport chain by NADH or its by has been to mitochondrial E. P. 2008; PubMed Scopus Google Scholar, A. P. 2008; PubMed Scopus Google this has to be P. J. 2008; 22: Google Scholar). is that Complex I to to electrons that be used for mitochondrial to showing that hNOA1 is in the with Complex I, the that Complex I through hNOA1 Complex I we evidence showing that of hNOA1 to Complex I-dependent O2 Overexpression of hNOA1 led to the of of hNOA1 led to mitochondria with The effects of hNOA1 and on mitochondrial morphology are to when mitochondrial fission proteins such as Drp1 or are D. K. R. J. A. J. Cell Sci. 2005; PubMed Scopus Google Scholar, A. N. K. 2005; PubMed Scopus Google Scholar), that hNOA1 play a role in mitochondrial large G proteins, 1 and are for the fusion of the A. J. Cell Sci. PubMed Google Scholar), and is for the fusion of the S. R. J. A. S. J.M. J. Cell. 2006; Full Text Full Text PDF PubMed Scopus Google Scholar). is for the fission of the J.M. S. A. J. J.M. Cell Biol. PubMed Scopus Google Scholar, S. B. Dev. Cell. Full Text Full Text PDF PubMed Scopus Google Scholar), but large G protein has been that is involved in fission of the IMM. is that hNOA1 be the large G protein that fission of the IMM. that of hNOA1 also cells to apoptotic stimuli, such as staurosporine, is with knockdown of fission proteins, such as Drp1 or M. Mol. Biol. Cell. 2004; 15: PubMed Scopus Google Scholar). In to its interaction with Complex I, we that hNOA1 interacts with DAP3, and of hNOA1 cells from apoptosis. the interaction is to the role of hNOA1 in apoptosis remains to be elucidated. Besides its role in apoptosis, we also that of hNOA1 affects mitochondrial respiration in a Complex I-dependent for roles in both respiration and apoptosis is its interaction with DAP3. DAP3 was as a of mitochondrial T. M. T. T. A. K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, E. A. K. H. A. PubMed Scopus Google Scholar, J. J. Biol. Chem. 2008; Full Text Full Text PDF PubMed Scopus Google Scholar), which are for of the proteins by the mitochondrial S. J. R. PubMed Scopus Google Scholar). of the proteins by mitochondrial are Complex I of the electron transport chain S. J. R. PubMed Scopus Google Scholar), and we Complex I, but also proteins, and as partners of hNOA1 by the interaction of with endogenous in and on cell and be to hNOA1 functions in mitochondrial proteins either through its interaction with DAP3 or mitochondrial proteins such as and from on how hNOA1 affects these and how mitochondrial functions with is of that mutations in the mitochondrial Complex I have been shown to in Complex I and P. J. Mol. Biol. PubMed Scopus Google Scholar), which to such as S. Cell Dev. Biol. PubMed Scopus Google Scholar) or mitochondrial E. M. L. E. P. R. G. M. 2007; PubMed Scopus Google Scholar). in Complex I and also to in mitochondrial morphology H.J. S. J. Cell 2005; PubMed Scopus Google Scholar). apoptosis, and dynamics are H.M. Neuspiel M. Wasiak S. Curr. 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