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CYC1 cytochrome c1 [ Homo sapiens (human) ]

Gene ID: 1537, updated on 25-Nov-2025
Official Symbol
CYC1provided by HGNC
Official Full Name
cytochrome c1provided by HGNC
Primary source
HGNC:HGNC:2579
See related
Ensembl:ENSG00000179091 MIM:123980; AllianceGenome:HGNC:2579
Gene type
protein coding
RefSeq status
REVIEWED
Organism
Homo sapiens
Lineage
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia; Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae; Homo
Also known as
UQCR4; MC3DN6
Summary
This gene encodes a subunit of the cytochrome bc1 complex, which plays an important role in the mitochondrial respiratory chain by transferring electrons from the Rieske iron-sulfur protein to cytochrome c. Mutations in this gene may cause mitochondrial complex III deficiency, nuclear type 6. [provided by RefSeq, Dec 2013]
Expression
Ubiquitous expression in heart (RPKM 77.6), duodenum (RPKM 50.4) and 25 other tissues See more
Orthologs
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See CYC1 in Genome Data Viewer
Location:
8q24.3
Exon count:
7
Annotation release Status Assembly Chr Location
RS_2025_08 current GRCh38.p14 (GCF_000001405.40) 8 NC_000008.11 (144095076..144097525)
RS_2025_08 current T2T-CHM13v2.0 (GCF_009914755.1) 8 NC_060932.1 (145255893..145258315)
RS_2024_09 previous assembly GRCh37.p13 (GCF_000001405.25) 8 NC_000008.10 (145149979..145152428)

Chromosome 8 - NC_000008.11Genomic Context describing neighboring genes Neighboring gene exosome component 4 Neighboring gene uncharacterized LOC124902038 Neighboring gene ATAC-STARR-seq lymphoblastoid silent region 19654 Neighboring gene microRNA 6847 Neighboring gene glycosylphosphatidylinositol anchor attachment 1 Neighboring gene H3K4me1 hESC enhancer GRCh37_chr8:145144930-145145430 Neighboring gene H3K4me1 hESC enhancer GRCh37_chr8:145145431-145145931 Neighboring gene Sharpr-MPRA regulatory region 12380 Neighboring gene ReSE screen-validated silencer GRCh37_chr8:145150053-145150248 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 28088 Neighboring gene SHANK associated RH domain interactor Neighboring gene ATAC-STARR-seq lymphoblastoid silent region 19656 Neighboring gene ATAC-STARR-seq lymphoblastoid silent region 19657 Neighboring gene ATAC-STARR-seq lymphoblastoid active region 28089 Neighboring gene Sharpr-MPRA regulatory region 2030 Neighboring gene MAF1 negative regulator of RNA polymerase III

Go to nucleotide: Graphics FASTA GenBank

  • Project title: Tissue-specific circular RNA induction during human fetal development
  • Description: 35 human fetal samples from 6 tissues (3 - 7 replicates per tissue) collected between 10 and 20 weeks gestational time were sequenced using Illumina TruSeq Stranded Total RNA
  • BioProject: PRJNA270632
  • Publication: PMID 26076956
  • Analysis date: Mon Apr 2 22:54:59 2018

Related articles in PubMed

  1. Isolation of a cDNA clone for human cytochrome c1 from a lambda gt11 expression library. Nishikimi M, et al. Biochem Biophys Res Commun, 1987 May 29. PMID 3036122
  2. CYC1 Predicts Poor Prognosis in Patients with Breast Cancer. Han Y, et al. Dis Markers, 2016. PMID 27239088, Free PMC Article
  3. Cytochrome c1 in ductal carcinoma in situ of breast associated with proliferation and comedo necrosis. Chishiki M, et al. Cancer Sci, 2017 Jul. PMID 28394473, Free PMC Article
  4. Assignment of the gene for the cytochrome c1 subunit of the mitochondrial cytochrome bc1 complex (CYC1) to human chromosome 8q24.3. Duncan AM, et al. Genomics, 1994 Jan 15. PMID 8188279
  5. Nucleotide sequence of a cDNA encoding the precursor to human cytochrome c1. Nishikimi M, et al. Nucleic Acids Res, 1988 Apr 25. PMID 2836796, Free PMC Article

See all (127) citations in PubMed

GeneRIFs: Gene References Into Functions

What's a GeneRIF?
  1. Physical contact between cytochrome c1 and cytochrome c increases the driving force for electron transfer.
    Title: Physical contact between cytochrome c(1) and cytochrome c increases the driving force for electron transfer.
  2. CYC1 inhibits cell proliferation, glycolytic activity and increases chemosensitivity to paclitaxel in ER-positive breast carcinoma cells
    Title: Cytochrome c1 as a favorable prognostic marker in estrogen receptor-positive breast carcinoma.
  3. these results indicate that CYC1 plays important roles in cell proliferation and comedo necrosis through the elevated oxidative phosphorylation activity in human ductal carcinoma in situ
    Title: Cytochrome c1 in ductal carcinoma in situ of breast associated with proliferation and comedo necrosis.
  4. results indicate that miR-661 plays a tumor suppressor role in OS mediated by the downregulation of CYC1, suggesting a potential mechanism underlying cell death resistance in Osteosarcoma.
    Title: MicroRNA-661 Enhances TRAIL or STS Induced Osteosarcoma Cell Apoptosis by Modulating the Expression of Cytochrome c1.
  5. CYC1 promoted tumor metastasis via suppressing activation of AMPK and contributed to tumor growth via facilitating production of ATP.
    Title: CYC1 Predicts Poor Prognosis in Patients with Breast Cancer.
  6. FASL, granzyme B, and cytochrome c blood expression reflects breast cancer progression and response to therapy. (Review)
    Title: Apoptosis Markers in Breast Cancer Therapy.
  7. our results provide evidence that CYC1 plays an important role in OS tumorigenesis, and modulation of CYC1 may be an effective strategy to potentiate OS to apoptotic induction by TRAIL.
    Title: CYC1 silencing sensitizes osteosarcoma cells to TRAIL-induced apoptosis.
  8. Mutations in CYC1 cause insulin-responsive hyperglycemia.
    Title: Mutations in CYC1, encoding cytochrome c1 subunit of respiratory chain complex III, cause insulin-responsive hyperglycemia.
  9. HeLa cells expressing non-cleavable cytochrome c1 maintain mitochondrial morphology and functions.
    Title: Caspase cleavage of cytochrome c1 disrupts mitochondrial function and enhances cytochrome c release.
  10. Decreased electron Transport Complex IV activity is associated with ulcerative colitis.
    Title: Mitochondrial respiratory chain in the colonic mucosal of patients with ulcerative colitis.
Submit: New GeneRIF Correction See all GeneRIFs (15)

Find tests for this gene in the NIH Genetic Testing Registry (GTR)

Review eQTL and phenotype association data in this region using PheGenI

Associated conditions

Description Tests
Mitochondrial complex III deficiency nuclear type 6
MedGen: C3809553 OMIM: 615453 GeneReviews: Not available
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See variants in ClinVar

See studies and variants in dbVar

See Variation Viewer (GRCh37.p13)

See Variation Viewer (GRCh38)

Protein interactions

Protein Gene Interaction Pubs
Vpr vpr A stable-isotope labeling by amino acids in cell culture coupled with mass spectrometry-based proteomics identifies downregulation of cytochrome c-1 (CYC1) expression by HIV-1 Vpr in Vpr transduced macrophages PubMed

Go to the HIV-1, Human Interaction Database

Products Interactant Other Gene Complex Source Pubs Description

Markers

Homology

Gene Ontology Provided by GOA

Function Evidence Code Pubs
enables electron transfer activity IEA
Inferred from Electronic Annotation
more info
  
enables heme binding IEA
Inferred from Electronic Annotation
more info
  
enables metal ion binding IEA
Inferred from Electronic Annotation
more info
  
enables protein binding IPI
Inferred from Physical Interaction
more info
 PubMed 
enables quinol-cytochrome-c reductase activity IEA
Inferred from Electronic Annotation
more info
  
Process Evidence Code Pubs
involved_in cellular respiration NAS
Non-traceable Author Statement
more info
 PubMed 
involved_in mitochondrial electron transport, ubiquinol to cytochrome c IBA
Inferred from Biological aspect of Ancestor
more info
  
involved_in mitochondrial electron transport, ubiquinol to cytochrome c NAS
Non-traceable Author Statement
more info
 PubMed 
involved_in proton transmembrane transport IEA
Inferred from Electronic Annotation
more info
  
involved_in response to glucagon IEA
Inferred from Electronic Annotation
more info
  
Component Evidence Code Pubs
located_in membrane HDA PubMed 
located_in membrane IEA
Inferred from Electronic Annotation
more info
  
located_in mitochondrial inner membrane IDA
Inferred from Direct Assay
more info
 PubMed 
is_active_in mitochondrial inner membrane IEA
Inferred from Electronic Annotation
more info
  
located_in mitochondrial inner membrane IEA
Inferred from Electronic Annotation
more info
  
located_in mitochondrial inner membrane TAS
Traceable Author Statement
more info
  
located_in mitochondrion HDA PubMed 
located_in mitochondrion HTP PubMed 
located_in mitochondrion IEA
Inferred from Electronic Annotation
more info
  
located_in mitochondrion TAS
Traceable Author Statement
more info
 PubMed 
located_in nucleus HDA PubMed 
part_of respiratory chain complex III IBA
Inferred from Biological aspect of Ancestor
more info
  
part_of respiratory chain complex III IEA
Inferred from Electronic Annotation
more info
  
part_of respiratory chain complex III IPI
Inferred from Physical Interaction
more info
 PubMed 
Preferred Names
cytochrome c1, heme protein, mitochondrial
Names
complex III subunit 4
complex III subunit IV
cytochrome b-c1 complex subunit 4
cytochrome c-1
ubiquinol-cytochrome-c reductase complex cytochrome c1 subunit
NP_001907.3

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RefSeqs maintained independently of Annotated Genomes

These reference sequences exist independently of genome builds. Explain

These reference sequences are curated independently of the genome annotation cycle, so their versions may not match the RefSeq versions in the current genome build. Identify version mismatches by comparing the version of the RefSeq in this section to the one reported in Genomic regions, transcripts, and products above.

Genomic

  1. NG_033872.2 RefSeqGene

    Range
    5002..7451
    Download
    GenBank, FASTA, Sequence Viewer (Graphics)

mRNA and Protein(s)

  1. NM_001916.5 → NP_001907.3  cytochrome c1, heme protein, mitochondrial precursor

    Status: REVIEWED

    Source sequence(s)
    AC104592
    Consensus CDS
    CCDS6415.1
    UniProtKB/Swiss-Prot
    P08574, Q5U062, Q6FHS7
    UniProtKB/TrEMBL
    Q8TBT6
    Related
    ENSP00000317159.4, ENST00000318911.5
    Conserved Domains (1) summary
    pfam02167
    Location:96 → 314
    Cytochrom_C1; Cytochrome C1 family

RefSeqs of Annotated Genomes: GCF_000001405.40-RS_2025_08

The following sections contain reference sequences that belong to a specific genome build. Explain

Reference GRCh38.p14 Primary Assembly

Genomic

  1. NC_000008.11 Reference GRCh38.p14 Primary Assembly

    Range
    144095076..144097525
    Download
    GenBank, FASTA, Sequence Viewer (Graphics)

Alternate T2T-CHM13v2.0

Genomic

  1. NC_060932.1 Alternate T2T-CHM13v2.0

    Range
    145255893..145258315
    Download
    GenBank, FASTA, Sequence Viewer (Graphics)
Nucleotide Protein
Heading Accession and Version
Protein Accession Links
GenPept Link UniProtKB Link
P08574.3 GenPept UniProtKB/Swiss-Prot:P08574

Gene LinkOut

The following LinkOut resources are supplied by external providers. These providers are responsible for maintaining the links.

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