FB2026_03 , released September 17, 2026
Gene: Dmel\SdhD
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General Information
Symbol
Dmel\SdhD
Species
D. melanogaster
Name
Succinate dehydrogenase, subunit D
Annotation Symbol
CG10219
Feature Type
FlyBase ID
FBgn0039112
Gene Model Status
Stock Availability
Enzyme Name (EC)
succinate dehydrogenase (1.3.5.1)
Gene Summary
Succinate dehydrogenase, subunit D (SdhD) encodes a membrane-anchoring subunit of the mitochondrial succinate dehydrogenase complex, also known as respiratory chain complex II. This complex catalyzes the sixth step of the of the tricarboxylic acid (TCA) cycle by oxidizing succinate to fumarate and also transfers electrons to quinones as part of the electron transport chain. [Date last reviewed: 2025-03-27] (FlyBase Gene Snapshot)
Key Links
Genomic Location
Cytogenetic map
Sequence location
Recombination map
3-80
RefSeq locus
NT_033777 REGION:23759483..23760600
Sequence
Other Genome Views
The following external sites may use different assemblies or annotations than FlyBase.
Function
Gene Ontology (GO) Annotations (10 terms)
Molecular Function (4 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (4 terms)
CV Term
Evidence
References
enables heme binding
inferred from biological aspect of ancestor with PANTHER:PTN001000243
inferred from sequence or structural similarity with UniProtKB:A5GZW8
inferred from sequence or structural similarity with UniProtKB:A5GZW8
inferred from sequence or structural similarity with UniProtKB:Q9CXV1
inferred from biological aspect of ancestor with PANTHER:PTN001000243
inferred from sequence or structural similarity with UniProtKB:A5GZW8
Biological Process (2 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (2 terms)
CV Term
Evidence
References
non-traceable author statement
inferred from biological aspect of ancestor with PANTHER:PTN001000243
inferred from biological aspect of ancestor with PANTHER:PTN001000243
inferred from sequence or structural similarity with UniProtKB:O14521
traceable author statement
Cellular Component (4 terms)
Terms Based on Experimental Evidence (0 terms)
Terms Based on Predictions or Assertions (4 terms)
CV Term
Evidence
References
located_in membrane
inferred from electronic annotation with InterPro:IPR007992, InterPro:IPR034804
inferred from electronic annotation with InterPro:IPR007992
non-traceable author statement
inferred from sequence or structural similarity with UniProtKB:A5GZW8
inferred from biological aspect of ancestor with PANTHER:PTN001000243
inferred from sequence or structural similarity with UniProtKB:A5GZW8
non-traceable author statement
Protein Family (UniProt)
Belongs to the CybS family. (Q9VCI5)
Catalytic Activity (EC/Rhea)
succinate dehydrogenase (quinone) activity
a quinone + succinate = fumarate + a quinol (1.3.5.1)
RHEA 40523:
Summaries
Gene Snapshot
Succinate dehydrogenase, subunit D (SdhD) encodes a membrane-anchoring subunit of the mitochondrial succinate dehydrogenase complex, also known as respiratory chain complex II. This complex catalyzes the sixth step of the of the tricarboxylic acid (TCA) cycle by oxidizing succinate to fumarate and also transfers electrons to quinones as part of the electron transport chain. [Date last reviewed: 2025-03-27]
Gene Group / Complex (FlyBase)
MITOCHONDRIAL COMPLEX II (SUCCINATE DEHYDROGENASE) SUBUNITS -
The succinate dehydrogenase complex is unique in that it functions in both the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC), wherein it is referred to as Complex II. It is a heterotetrameric protein complex that is anchored to the inner mitochondrial membrane by two integral membrane proteins, Sdh3 (SDHC) and Sdh4 (SDHD). This Sdh3/Sdh4 dimer binds the peripheral membrane protein Sdh2 (SDHB), which tethers the Sdh1 (SDHA) subunit to the complex. Sdh1 harbors a covalently bound FAD cofactor that is required for the oxidation of succinate to fumarate in the TCA cycle. The two electrons that result from succinate oxidation are channeled through the three iron-sulfur clusters in Sdh2 to ubiquinone, which interacts with the complex via the Sdh3/Sdh4 membrane anchor, and thereby reduce it to ubiquinol as part of the ETC. (Adapted from PMID:24954416 and PMID:37490987.)
MITOCHONDRIAL COMPLEX II (SUCCINATE DEHYDROGENASE) -
Mitochondrial complex II/Succinate Dehydrogenase is a heterotetrameric protein complex anchored to the inner mitochondrial membrane via two integral membrane subunits. It functions both in the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC) by catalysing the oxidation of succinate to fumarate and then, via electron transfer, reducing ubiquinone to ubiquinol. (Adapted from PMID:24954416.)
MITOCHONDRIAL COMPLEX II (SUCCINATE DEHYDROGENASE) - TESTIS-SPECIFIC VARIANT -
Mitochondrial complex II/Succinate Dehydrogenase is a heterotetrameric protein complex anchored to the inner mitochondrial membrane via two integral membrane subunits. It functions both in the tricarboxylic acid (TCA) cycle and the electron transport chain (ETC) by catalysing the oxidation of succinate to fumarate and then, via electron transfer, reducing ubiquinone to ubiquinol. (Adapted from PMID:24954416.)
Pathway (FlyBase)
TRICARBOXYLIC ACID (TCA) CYCLE -
The tricarboxylic acid (TCA) cycle is a central metabolic process that occurs in mitochondria. It consists of a cyclic series of chemical reactions that harness high-energy electrons from nutrients to produce energy (ATP). Each turn of the TCA cycle oxidizes one acetyl-CoA to two CO2 molecules and yields one GTP or ATP and 6 electrons in the form of four reducing equivalents (three NADH and one FADH2). Then, these electron carriers transfer their electrons onto the electron transport chain (ETC) complexes to generate ATP in a process known as oxidative phosphorylation (OXPHOS). The TCA cycle intermediates can also be used as precursors for the biosynthesis of amino acids, fatty acids and porphyrins and for gluconeogenesis. (Adapted from PMID:36581208).
OXIDATIVE PHOSPHORYLATION -
Oxidative phosphorylation (OXPHOS) is the coordinated transfer of electrons and protons leading to the production of ATP. The OXPHOS system is composed of five mitochondrial inner membrane complexes, Complexes I-IV comprise the electron respiratory chain and Complex V the ATP synthase. Complexes I and II oxidize the electron donors NADH and FADH2, respectively, derived from the tricarboxylic acid (TCA) cycle, and the electrons are transferred to the electron carrier ubiquinone which shuttles them to Complex III. Cytochrome c transfers electrons between Complex III and the terminal complex in the respiratory chain, Complex IV. Complex IV catalyzes electron transfer from reduced cytochrome c to oxygen. Complex I, II and IV couple electron transfer to proton transport across the inner mitochondrial membrane into the inner membrane space. This generates a proton electrochemical gradient which is used to drive the synthesis of ATP from ADP and inorganic phosphate by ATP synthase (Complex V). (Adapted from PMID:23356252 and PMID:11331900.)
Protein Function (UniProtKB)
Membrane-anchoring subunit of succinate dehydrogenase (SDH) that is involved in complex II of the mitochondrial electron transport chain and is responsible for transferring electrons from succinate to ubiquinone (coenzyme Q).
(UniProt, Q9VCI5)
Gene Model and Products
Number of Transcripts
1
Number of Unique Polypeptides
1

Please see the JBrowse view of Dmel\SdhD for information on other features

To submit a correction to a gene model please use the Contact FlyBase form

Protein Domains (via Pfam)
Isoform displayed:
Pfam protein domains
InterPro name
classification
start
end
Protein Domains (via SMART)
Isoform displayed:
SMART protein domains
InterPro name
classification
start
end
Structure
Protein 3D structure   (Predicted by AlphaFold)   (AlphaFold entry Q9VCI5)

If you don't see a structure in the viewer, refresh your browser.
Model Confidence:
  • Very high (pLDDT > 90)
  • Confident (90 > pLDDT > 70)
  • Low (70 > pLDDT > 50)
  • Very low (pLDDT < 50)

AlphaFold produces a per-residue confidence score (pLDDT) between 0 and 100. Some regions with low pLDDT may be unstructured in isolation.

Experimentally Determined Structures
Crossreferences
Comments on Gene Model

Gene model reviewed during 5.47

Transcript Data
Annotated Transcripts
Name
FlyBase ID
RefSeq ID
Length (nt)
Assoc. CDS (aa)
FBtr0084466
894
182
Additional Transcript Data and Comments
Reported size (kB)
Comments
External Data
Crossreferences
Polypeptide Data
Annotated Polypeptides
Name
FlyBase ID
Predicted MW (kDa)
Length (aa)
Theoretical pI
UniProt
RefSeq ID
GenBank
FBpp0083857
19.3
182
10.93
Polypeptides with Identical Sequences

There is only one protein coding transcript and one polypeptide associated with this gene

Additional Polypeptide Data and Comments
Reported size (kDa)
Comments
External Data
Subunit Structure (UniProtKB)

Forms part of complex II containing four subunits: a flavoprotein (FP), an iron-sulfur protein (IP) and a cytochrome b composed of a large and a small subunit.

(UniProt, Q9VCI5)
Linkouts
Sequences Consistent with the Gene Model
Mapped Features

Click to get a list of regulatory features (enhancers, TFBS, etc.) and gene disruptions (point mutations, indels, etc.) within or overlapping Dmel\SdhD using the Feature Mapper tool.

External Data
Crossreferences
Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
Linkouts
Expression Data
Testis-specificity index

The testis specificity index was calculated from modENCODE tissue expression data by Vedelek et al., 2018 to indicate the degree of testis enrichment compared to other tissues. Scores range from -2.52 (underrepresented) to 5.2 (very high testis bias).

1.57

Transcript Expression
Additional Descriptive Data
Marker for
 
Subcellular Localization
CV Term
Polypeptide Expression
mass spectroscopy
Stage
Tissue/Position (including subcellular localization)
Reference
Additional Descriptive Data
Marker for
 
Subcellular Localization
CV Term
Evidence
References
Expression Deduced from Reporters
High-Throughput Expression Data
Associated Tools

JBrowse - Visual display of RNA-Seq signals

View Dmel\SdhD in JBrowse
RNA-Seq by Region - Search RNA-Seq expression levels by exon or genomic region
Reference
See Gelbart and Emmert, 2013 for analysis details and data files for all genes.
Developmental Proteome: Life Cycle
Developmental Proteome: Embryogenesis
External Data and Images
Linkouts
DRscDB - A single-cell RNA-seq resource for data mining and data comparison across species
EMBL-EBI Single Cell Expression Atlas - Single cell expression across species
FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
FlyAtlas2 - A Drosophila melanogaster expression atlas with RNA-Seq, miRNA-Seq and sex-specific data
Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
Flygut - An atlas of the Drosophila adult midgut
Images
Alleles, Insertions, Transgenic Constructs, and Aberrations
Classical and Insertion Alleles ( 4 )
For All Classical and Insertion Alleles Show
 
Other relevant insertions
Transgenic Constructs ( 4 )
For All Alleles Carried on Transgenic Constructs Show
Transgenic constructs containing/affecting coding region of SdhD
Transgenic constructs containing regulatory region of SdhD
Aberrations (Deficiencies and Duplications) ( 2 )
Inferred from experimentation ( 2 )
Gene partially disrupted in
Inferred from location ( 5 )
Variants
Variant Molecular Consequences
Alleles Representing Disease-Implicated Variants
Phenotypes
For more details about a specific phenotype click on the relevant allele symbol.
Lethality
Allele
Sterility
Allele
Other Phenotypes
Allele
Phenotype manifest in
Allele
Orthologs
Human Orthologs (via DIOPT v9.1)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
Homo sapiens (Human) (1)
12 of 14
Yes
Yes
1  
Model Organism Orthologs (via DIOPT v9.1)
Species\Gene Symbol
Score
Best Score
Best Reverse Score
Alignment
Complementation?
Transgene?
Rattus norvegicus (Norway rat) (1)
12 of 14
Yes
Yes
Mus musculus (laboratory mouse) (1)
11 of 14
Yes
Yes
Xenopus tropicalis (Western clawed frog) (1)
9 of 13
Yes
Yes
Danio rerio (Zebrafish) (2)
12 of 14
Yes
Yes
12 of 14
Yes
Yes
Caenorhabditis elegans (Nematode, roundworm) (1)
11 of 14
Yes
Yes
Anopheles gambiae (African malaria mosquito) (1)
12 of 12
Yes
Yes
Arabidopsis thaliana (thale-cress) (0)
Saccharomyces cerevisiae (Brewer's yeast) (3)
8 of 13
Yes
Yes
7 of 13
No
Yes
6 of 13
No
Yes
Schizosaccharomyces pombe (Fission yeast) (1)
8 of 12
Yes
Yes
Escherichia coli (enterobacterium) (0)
Other Organism Orthologs (via OrthoDB)
Data provided directly from OrthoDB:SdhD. Refer to their site for version information.
Paralogs
Paralogs (via DIOPT v9.1)
Human Disease Associations
FlyBase Human Disease Model Reports
    Disease Ontology (DO) Annotations
    Models Based on Experimental Evidence ( 0 )
    Allele
    Disease
    Evidence
    References
    Potential Models Based on Orthology ( 2 )
    Modifiers Based on Experimental Evidence ( 0 )
    Allele
    Disease
    Interaction
    References
    Disease Associations of Human Orthologs (via DIOPT v9.1 and OMIM)
    Note that ortholog calls supported by only 1 or 2 algorithms (DIOPT score < 3) are not shown.
    Functional Complementation Data
    Functional complementation data is computed by FlyBase using a combination of the orthology data obtained from DIOPT and OrthoDB and the allele-level genetic interaction data curated from the literature.
    Interactions
    Summary of Physical Interactions
    Interaction Browsers

    Please see the Physical Interaction reports below for full details
    RNA-protein
    Physical Interaction
    Assay
    References
    Summary of Genetic Interactions
    Interaction Browsers

    Please look at the allele data for full details of the genetic interactions
    Starting gene(s)
    Interaction type
    Interacting gene(s)
    Reference
    Starting gene(s)
    Interaction type
    Interacting gene(s)
    Reference
    External Data
    Subunit Structure (UniProtKB)
    Forms part of complex II containing four subunits: a flavoprotein (FP), an iron-sulfur protein (IP) and a cytochrome b composed of a large and a small subunit.
    (UniProt, Q9VCI5 )
    Linkouts
    BioGRID - A database of protein and genetic interactions.
    DroID - A comprehensive database of gene and protein interactions.
    MIST (protein-protein) - An integrated Molecular Interaction Database
    Pathways
    Signaling Pathways (FlyBase)
    Metabolic Pathways
    External Links
    KEGG Metabolic Pathways - A collection of manually drawn metabolic pathway maps representing knowledge of molecular interaction, reaction and relation networks.
    Reactome Metabolic Pathways - An open-source, open access, manually curated and peer-reviewed metabolic pathway database.
    External Data
    Linkouts
    KEGG Pathways - A collection of manually drawn pathway maps representing knowledge of molecular interaction, reaction and relation networks.
    Reactome - An open-source, open access, manually curated and peer-reviewed pathway database.
    Class of Gene
    Genomic Location and Detailed Mapping Data
    Chromosome (arm)
    3R
    Recombination map
    3-80
    Cytogenetic map
    Sequence location
    FlyBase Computed Cytological Location
    Cytogenetic map
    Evidence for location
    95B1-95B1
    Limits computationally determined from genome sequence between P{PZ}l(3)0468404684 and P{PZ}Atg600096
    Experimentally Determined Cytological Location
    Cytogenetic map
    Notes
    References
    Experimentally Determined Recombination Data
    Location
    Left of (cM)
    Right of (cM)
    Notes
    Stocks and Reagents
    Stocks (7)
    Genomic Clones (13)
     

    Please Note FlyBase no longer curates genomic clone accessions so this list may not be complete

    cDNA Clones (65)
     

    Please Note This section lists cDNAs and ESTs that fall within the genomic extent of the gene model, which may include cDNAs and ESTs of genes within introns, or of overlapping genes. Please see JBrowse for alignment of the cDNAs and ESTs to the gene model.

    cDNA clones, fully sequenced
    BDGP DGC clones
    Other clones
      Drosophila Genomics Resource Center cDNA clones

      For each fully sequenced cDNA the DGRC maintains various forms of the cDNA (e.g tagged or untagged) in several different host vectors for subsequent cloning and expression in Drosophila and Drosophila cell lines.

      cDNA Clones, End Sequenced (ESTs)
      RNAi and Array Information
      Linkouts
      DRSC - Results frm RNAi screens
      Antibody Information
      Laboratory Generated Antibodies
       
      Commercially Available Antibodies
       
      Cell Line Information
      Publicly Available Cell Lines
       
        Other Stable Cell Lines
         
          Other Comments
          Relationship to Other Genes
          Source for database merge of

          Source for merge of: CG10219 BEST:GH27735

          Additional comments
          Nomenclature History
          Source for database identify of

          Source for identity of: SdhD CG10219

          Nomenclature comments
          Etymology
          Synonyms and Secondary IDs (12)
          Datasets (0)
          Study focus (0)
          Experimental Role
          Project
          Project Type
          Title
          Study result (0)
          Result
          Result Type
          Title
          External Crossreferences and Linkouts ( 52 )
          Sequence Crossreferences
          NCBI Gene - Gene integrates information from a wide range of species. A record may include nomenclature, Reference Sequences (RefSeqs), maps, pathways, variations, phenotypes, and links to genome-, phenotype-, and locus-specific resources worldwide.
          GenBank Nucleotide - A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
          GenBank Protein - A collection of sequences from several sources, including translations from annotated coding regions in GenBank, RefSeq and TPA, as well as records from SwissProt, PIR, PRF, and PDB.
          RefSeq - A comprehensive, integrated, non-redundant, well-annotated set of reference sequences including genomic, transcript, and protein.
          UniProt/GCRP - The gene-centric reference proteome (GCRP) provides a 1:1 mapping between genes and UniProt accessions in which a single 'canonical' isoform represents the product(s) of each protein-coding gene.
          UniProt/Swiss-Prot - Manually annotated and reviewed records of protein sequence and functional information
          Other crossreferences
          AlphaFold DB - AlphaFold provides open access to protein structure predictions for the human proteome and other key proteins of interest, to accelerate scientific research.
          DRscDB - A single-cell RNA-seq resource for data mining and data comparison across species
          EMBL-EBI Single Cell Expression Atlas - Single cell expression across species
          FlyAtlas2 - A Drosophila melanogaster expression atlas with RNA-Seq, miRNA-Seq and sex-specific data
          FlyMine - An integrated database for Drosophila genomics
          KEGG Genes - Molecular building blocks of life in the genomic space.
          MARRVEL_MODEL - MARRVEL (model organism gene)
          Linkouts
          BioGRID - A database of protein and genetic interactions.
          Drosophila Genomics Resource Center - Drosophila Genomics Resource Center (DGRC) cDNA clones
          DroID - A comprehensive database of gene and protein interactions.
          DRSC - Results frm RNAi screens
          Eukaryotic Promoter Database - A collection of databases of experimentally validated promoters for selected model organisms.
          FlyAtlas - Adult expression by tissue, using Affymetrix Dros2 array
          FlyCyc Genes - Genes from a BioCyc PGDB for Dmel
          Fly-FISH - A database of Drosophila embryo and larvae mRNA localization patterns
          Flygut - An atlas of the Drosophila adult midgut
          FlyMet - A comprehensive tissue-specific metabolomics resource for Drosophila.
          iBeetle-Base - RNAi phenotypes in the red flour beetle (Tribolium castaneum)
          KEGG Metabolic Pathways - A collection of manually drawn metabolic pathway maps representing knowledge of molecular interaction, reaction and relation networks.
          KEGG Pathways - A collection of manually drawn pathway maps representing knowledge of molecular interaction, reaction and relation networks.
          MIST (protein-protein) - An integrated Molecular Interaction Database
          Reactome - An open-source, open access, manually curated and peer-reviewed pathway database.
          Reactome Metabolic Pathways - An open-source, open access, manually curated and peer-reviewed metabolic pathway database.
          References (58)