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1.N.6.1.2
The mammalian mitochondrial membrane fusion complex, Mitofusin 1/2 (Mfn1)/Mfn2/Optical Atrophy Protein 1 (OPA1) complex (the equivalent of the yeast Ugo1 protein)/dynamin-related protein 1 Drp1 (Chandhok et al. 2018). Mfn1 and Mfn2 are two very similar (60% identity) GTPase dynamin-like proteins in the outer mitochondrial membrane (members of the CDD P-loop[ NTPase Family) while OPA1 is a sequence divergent GTPase in the inner membrane (Chen and Chan, 2010).  Mfn2 plays roles in mitochondrial fusion and mitochondrial endoplasmic reticulum interactions (Ranieri et al. 2013; Schneeberger et al. 2013). Mfn2, when defective can give rise to Charcot-Marie-Tooth disease, diabetes, neurodegenerative diseases, obesity and vascular diseases (Chandhok et al. 2018).  It may also function in  insulin-dependent myogenesis (Pawlikowska et al. 2007). Drp1 (DLP1, DNM1L) mediates membrane fusion and fission through oligomerization into membrane-associated tubular structures that wrap around the scission site to constrict and sever the mitochondrial membrane in a GTP hydrolysis-dependent mechanism (Smirnova et al. 2001; Taguchi et al. 2007). Sequences flanking the TMSs facilitate membrane fusion by mitofusin (Huang et al. 2017). Opa1 is a mitochondrial remodeling protein with a dual role in maintaining mitochondrial morphology and energetics by mediating inner membrane fusion and maintaining the cristae structure. This and the fusion/fission process by dynamins is described by Lee and Yoon 2018. MFN2 deficiency affects calcium homeostasis in lung adenocarcinoma cells via downregulation of UCP4 (Zhang et al. 2023).  Inhibition of MFN1 restores tamoxifen-induced apoptosis in resistant cells by disrupting aberrant mitochondrial fusion dynamics (Song et al. 2024). Mfn2 regulates calcium homeostasis and suppresses PASMCs proliferation via interaction with IP3R3 to mitigate pulmonary arterial hypertension (Wang et al. 2025).

Accession Number:O60313
Protein Name:Dynamin-like 120 kDa protein, mitochondrial
Length:960
Molecular Weight:111631.00
Species:Homo sapiens (Human) [9606]
Number of TMSs:1
Location1 / Topology2 / Orientation3: Mitochondrion inner membrane1 / Single-pass membrane protein2
Substrate

Cross database links:

RefSeq: NP_056375.2    NP_570849.2   
Entrez Gene ID: 4976   
Pfam: PF00350   
OMIM: 125250  phenotype
165500  phenotype
605290  gene
KEGG: hsa:4976   

Gene Ontology

GO:0030425 C:dendrite
GO:0016021 C:integral to membrane
GO:0030061 C:mitochondrial crista
GO:0005758 C:mitochondrial intermembrane space
GO:0005741 C:mitochondrial outer membrane
GO:0005525 F:GTP binding
GO:0003924 F:GTPase activity
GO:0000287 F:magnesium ion binding
GO:0006915 P:apoptosis
GO:0019896 P:axon transport of mitochondrion
GO:0007007 P:inner mitochondrial membrane organization
GO:0000266 P:mitochondrial fission
GO:0008053 P:mitochondrial fusion
GO:0045768 P:positive regulation of anti-apoptosis
GO:0050896 P:response to stimulus
GO:0007601 P:visual perception

References (22)

[1] “Prediction of the coding sequences of unidentified human genes. IX. The complete sequences of 100 new cDNA clones from brain which can code for large proteins in vitro.”  Nagase T.et.al.   9628581
[2] “The DNA sequence, annotation and analysis of human chromosome 3.”  Muzny D.M.et.al.   16641997
[3] “The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).”  The MGC Project Teamet.al.   15489334
[4] “Mutation spectrum and splicing variants in the OPA1 gene.”  Delettre C.et.al.   11810270
[5] “Nuclear gene OPA1, encoding a mitochondrial dynamin-related protein, is mutated in dominant optic atrophy.”  Delettre C.et.al.   11017079
[6] “OPA1, encoding a dynamin-related GTPase, is mutated in autosomal dominant optic atrophy linked to chromosome 3q28.”  Alexander C.et.al.   11017080
[7] “Regulation of mitochondrial morphology through proteolytic cleavage of OPA1.”  Ishihara N.et.al.   16778770
[8] “Improved titanium dioxide enrichment of phosphopeptides from HeLa cells and high confident phosphopeptide identification by cross-validation of MS/MS and MS/MS/MS spectra.”  Yu L.-R.et.al.   17924679
[9] “Lysine acetylation targets protein complexes and co-regulates major cellular functions.”  Choudhary C.et.al.   19608861
[10] “OPA1 mutations in patients with autosomal dominant optic atrophy and evidence for semi-dominant inheritance.”  Pesch U.E.A.et.al.   11440988
[11] “Spectrum, frequency and penetrance of OPA1 mutations in dominant optic atrophy.”  Toomes C.et.al.   11440989
[12] “A comprehensive survey of mutations in the OPA1 gene in patients with autosomal dominant optic atrophy.”  Thiselton D.L.et.al.   12036970
[13] “A novel mutation in the OPA1 gene in a Japanese patient with optic atrophy.”  Shimizu S.et.al.   12566046
[14] “Fourteen novel OPA1 mutations in autosomal dominant optic atrophy including two de novo mutations in sporadic optic atrophy.”  Baris O.et.al.   14961560
[15] “Dominant optic atrophy, sensorineural hearing loss, ptosis, and ophthalmoplegia: a syndrome caused by a missense mutation in OPA1.”  Payne M.et.al.   15531309
[16] “Dominant optic atrophy: correlation between clinical and molecular genetic studies.”  Puomila A.et.al.   15948788
[17] “OPA1 R445H mutation in optic atrophy associated with sensorineural deafness.”  Amati-Bonneau P.et.al.   16240368
[18] “OPA1 mutations and mitochondrial DNA haplotypes in autosomal dominant optic atrophy.”  Han J.et.al.   16617242
[19] “Novel mutations in the OPA1 gene and associated clinical features in Japanese patients with optic atrophy.”  Nakamura M.et.al.   16513463
[20] “Progressive external ophthalmoplegia and vision and hearing loss in a patient with mutations in POLG2 and OPA1.”  Ferraris S.et.al.   18195150
[21] “Molecular screening of 980 cases of suspected hereditary optic neuropathy with a report on 77 novel OPA1 mutations.”  Ferre M.et.al.   19319978
[22] “Acute and late-onset optic atrophy due to a novel OPA1 mutation leading to a mitochondrial coupling defect.”  Nochez Y.et.al.   19325939
Structure:
6JTG     

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Predict TMSs (Predict number of transmembrane segments)
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FASTA formatted sequence
1:	MWRLRRAAVA CEVCQSLVKH SSGIKGSLPL QKLHLVSRSI YHSHHPTLKL QRPQLRTSFQ 
61:	QFSSLTNLPL RKLKFSPIKY GYQPRRNFWP ARLATRLLKL RYLILGSAVG GGYTAKKTFD 
121:	QWKDMIPDLS EYKWIVPDIV WEIDEYIDFE KIRKALPSSE DLVKLAPDFD KIVESLSLLK 
181:	DFFTSGSPEE TAFRATDRGS ESDKHFRKVS DKEKIDQLQE ELLHTQLKYQ RILERLEKEN 
241:	KELRKLVLQK DDKGIHHRKL KKSLIDMYSE VLDVLSDYDA SYNTQDHLPR VVVVGDQSAG 
301:	KTSVLEMIAQ ARIFPRGSGE MMTRSPVKVT LSEGPHHVAL FKDSSREFDL TKEEDLAALR 
361:	HEIELRMRKN VKEGCTVSPE TISLNVKGPG LQRMVLVDLP GVINTVTSGM APDTKETIFS 
421:	ISKAYMQNPN AIILCIQDGS VDAERSIVTD LVSQMDPHGR RTIFVLTKVD LAEKNVASPS 
481:	RIQQIIEGKL FPMKALGYFA VVTGKGNSSE SIEAIREYEE EFFQNSKLLK TSMLKAHQVT 
541:	TRNLSLAVSD CFWKMVRESV EQQADSFKAT RFNLETEWKN NYPRLRELDR NELFEKAKNE 
601:	ILDEVISLSQ VTPKHWEEIL QQSLWERVST HVIENIYLPA AQTMNSGTFN TTVDIKLKQW 
661:	TDKQLPNKAV EVAWETLQEE FSRFMTEPKG KEHDDIFDKL KEAVKEESIK RHKWNDFAED 
721:	SLRVIQHNAL EDRSISDKQQ WDAAIYFMEE ALQARLKDTE NAIENMVGPD WKKRWLYWKN 
781:	RTQEQCVHNE TKNELEKMLK CNEEHPAYLA SDEITTVRKN LESRGVEVDP SLIKDTWHQV 
841:	YRRHFLKTAL NHCNLCRRGF YYYQRHFVDS ELECNDVVLF WRIQRMLAIT ANTLRQQLTN 
901:	TEVRRLEKNV KEVLEDFAED GEKKIKLLTG KRVQLAEDLK KVREIQEKLD AFIEALHQEK