Human Gene CYCS (ENST00000305786.6) Description and Page Index
  Description: Homo sapiens cytochrome c, somatic (CYCS), mRNA. (from RefSeq NM_018947)
RefSeq Summary (NM_018947): This gene encodes a small heme protein that functions as a central component of the electron transport chain in mitochondria. The encoded protein associates with the inner membrane of the mitochondrion where it accepts electrons from cytochrome b and transfers them to the cytochrome oxidase complex. This protein is also involved in initiation of apoptosis. Mutations in this gene are associated with autosomal dominant nonsyndromic thrombocytopenia. Numerous processed pseudogenes of this gene are found throughout the human genome.[provided by RefSeq, Jul 2010]. Sequence Note: This RefSeq record was created from transcript and genomic sequence data to make the sequence consistent with the reference genome assembly. The genomic coordinates used for the transcript record were based on transcript alignments. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications. ##Evidence-Data-START## Transcript exon combination :: AL713681.1, BC009582.1 [ECO:0000332] ##Evidence-Data-END## ##RefSeq-Attributes-START## gene product(s) localized to mito. :: reported by MitoCarta MANE Ensembl match :: ENST00000305786.7/ ENSP00000307786.2 RefSeq Select criteria :: based on single protein-coding transcript ##RefSeq-Attributes-END##
Gencode Transcript: ENST00000305786.6
Gencode Gene: ENSG00000172115.8
Transcript (Including UTRs)
   Position: hg38 chr7:25,120,091-25,125,361 Size: 5,271 Total Exon Count: 3 Strand: -
Coding Region
   Position: hg38 chr7:25,123,701-25,124,119 Size: 419 Coding Exon Count: 2 

Page IndexSequence and LinksUniProtKB CommentsMalaCardsCTDRNA-Seq Expression
Microarray ExpressionRNA StructureProtein StructureOther SpeciesGO AnnotationsmRNA Descriptions
PathwaysOther NamesMethods
Data last updated: 2019-09-04

-  Sequence and Links to Tools and Databases
Genomic Sequence (chr7:25,120,091-25,125,361)mRNA (may differ from genome)Protein (105 aa)
Gene SorterGenome BrowserOther Species FASTAGene interactionsTable SchemaBioGPS
CGAPEnsemblEntrez GeneExonPrimerGeneCardsHGNC
ReactomeStanford SOURCEUniProtKBWikipedia

-  Comments and Description Text from UniProtKB
DESCRIPTION: RecName: Full=Cytochrome c;
FUNCTION: Electron carrier protein. The oxidized form of the cytochrome c heme group can accept an electron from the heme group of the cytochrome c1 subunit of cytochrome reductase. Cytochrome c then transfers this electron to the cytochrome oxidase complex, the final protein carrier in the mitochondrial electron-transport chain.
FUNCTION: Plays a role in apoptosis. Suppression of the anti- apoptotic members or activation of the pro-apoptotic members of the Bcl-2 family leads to altered mitochondrial membrane permeability resulting in release of cytochrome c into the cytosol. Binding of cytochrome c to Apaf-1 triggers the activation of caspase-9, which then accelerates apoptosis by activating other caspases.
INTERACTION: O14727:APAF1; NbExp=6; IntAct=EBI-446479, EBI-446492;
SUBCELLULAR LOCATION: Mitochondrion intermembrane space. Note=Loosely associated with the inner membrane.
PTM: Binds 1 heme group per subunit.
PTM: Phosphorylation at Tyr-49 and Tyr-98 both reduce by half the turnover in the reaction with cytochrome c oxidase, down- regulating mitochondrial respiration (By similarity).
DISEASE: Defects in CYCS are the cause of thrombocytopenia type 4 (THC4) [MIM:612004]; also known as autosomal dominant thrombocytopenia type 4. Thrombocytopenia is the presence of relatively few platelets in blood. THC4 is a non-syndromic form of thrombocytopenia. Clinical manifestations of thrombocytopenia are absent or mild. THC4 may be caused by dysregulated platelet formation.
SIMILARITY: Belongs to the cytochrome c family.
WEB RESOURCE: Name=Protein Spotlight; Note=Life shuttle - Issue 76 of November 2006; URL="";

-  MalaCards Disease Associations
  MalaCards Gene Search: CYCS
Diseases sorted by gene-association score: thrombocytopenia 4* (1328), autosomal thrombocytopenia with normal platelets* (247), thrombocytopenia (17), orbital granuloma (14), telangiectatic osteogenic sarcoma (10), myasthenic syndrome, congenital, 9, associated with acetylcholine receptor deficiency (10), bone cancer (9), alzheimer disease mitochondrial (9), tyrosinemia, type i (9), optic atrophy 1 (8), bladder transitional cell papilloma (7), lung cancer (7), cardiac arrest (7), hemangioma (6), breast adenocarcinoma (6), colorectal cancer (5), chronic orbital inflammation (5), blue cone monochromacy (5), hemorrhagic cystitis (5), spastic paraplegia 7, autosomal recessive (5), huntington disease (4), suppression amblyopia (4), vestibular nystagmus (4), cardiomyopathy, hypertrophic, 2 (4), carbuncle (4), ischemia (3), cervical cancer, somatic (3), prostate cancer (2), hepatocellular carcinoma (2), alzheimer disease (2), toxic encephalopathy (1), parkinson disease, late-onset (1), hematologic cancer (1), osteosarcoma, somatic (1), neuroblastoma (1), autonomic nervous system neoplasm (1), stroke, ischemic (1), amyotrophic lateral sclerosis 1 (1)
* = Manually curated disease association

-  Comparative Toxicogenomics Database (CTD)
  The following chemicals interact with this gene           more ... click here to view the complete list

-  RNA-Seq Expression Data from GTEx (53 Tissues, 570 Donors)
  Highest median expression: 91.11 RPKM in Heart - Left Ventricle
Total median expression: 1277.42 RPKM

View in GTEx track of Genome Browser    View at GTEx portal     View GTEx Body Map

+  Microarray Expression Data
  Press "+" in the title bar above to open this section.

-  mRNA Secondary Structure of 3' and 5' UTRs
RegionFold EnergyBasesEnergy/Base
Display As
5' UTR -60.20170-0.354 Picture PostScript Text
3' UTR -1258.703610-0.349 Picture PostScript Text

The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.

-  Protein Domain and Structure Information
  InterPro Domains: Graphical view of domain structure
IPR002327 - Cyt_c_1A/1B
IPR009056 - Cyt_c_dom
IPR003088 - Cyt_c_I

Pfam Domains:
PF00034 - Cytochrome c

Protein Data Bank (PDB) 3-D Structure
MuPIT help


- X-ray MuPIT

ModBase Predicted Comparative 3D Structure on P99999
The pictures above may be empty if there is no ModBase structure for the protein. The ModBase structure frequently covers just a fragment of the protein. You may be asked to log onto ModBase the first time you click on the pictures. It is simplest after logging in to just click on the picture again to get to the specific info on that model.

-  Orthologous Genes in Other Species
  Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
MouseRatZebrafishD. melanogasterC. elegansS. cerevisiae
Genome BrowserNo orthologNo orthologNo orthologNo orthologNo ortholog
Gene Details     
Gene Sorter     
Protein Sequence     

-  Gene Ontology (GO) Annotations with Structured Vocabulary
  Molecular Function:
GO:0005515 protein binding
GO:0009055 electron carrier activity
GO:0020037 heme binding
GO:0045155 electron transporter, transferring electrons from CoQH2-cytochrome c reductase complex and cytochrome c oxidase complex activity
GO:0046872 metal ion binding
GO:0004722 protein serine/threonine phosphatase activity

Biological Process:
GO:0006122 mitochondrial electron transport, ubiquinol to cytochrome c
GO:0006123 mitochondrial electron transport, cytochrome c to oxygen
GO:0006470 protein dephosphorylation
GO:0006915 apoptotic process
GO:0007005 mitochondrion organization
GO:0008635 activation of cysteine-type endopeptidase activity involved in apoptotic process by cytochrome c
GO:0034599 cellular response to oxidative stress
GO:0045333 cellular respiration
GO:0055114 oxidation-reduction process
GO:0097193 intrinsic apoptotic signaling pathway

Cellular Component:
GO:0000159 protein phosphatase type 2A complex
GO:0005634 nucleus
GO:0005739 mitochondrion
GO:0005743 mitochondrial inner membrane
GO:0005758 mitochondrial intermembrane space
GO:0005829 cytosol
GO:0070469 respiratory chain

-  Descriptions from all associated GenBank mRNAs
  AK056360 - Homo sapiens cDNA FLJ31798 fis, clone NT2RI2009005.
LF207137 - JP 2014500723-A/14640: Polycomb-Associated Non-Coding RNAs.
MA442714 - JP 2018138019-A/14640: Polycomb-Associated Non-Coding RNAs.
AL713681 - Homo sapiens mRNA; cDNA DKFZp761O0217 (from clone DKFZp761O0217).
JD101411 - Sequence 82435 from Patent EP1572962.
JD269536 - Sequence 250560 from Patent EP1572962.
JD229989 - Sequence 211013 from Patent EP1572962.
JD281949 - Sequence 262973 from Patent EP1572962.
JD296376 - Sequence 277400 from Patent EP1572962.
JD093038 - Sequence 74062 from Patent EP1572962.
JD184167 - Sequence 165191 from Patent EP1572962.
JD207967 - Sequence 188991 from Patent EP1572962.
JD074281 - Sequence 55305 from Patent EP1572962.
JD373597 - Sequence 354621 from Patent EP1572962.
JD557615 - Sequence 538639 from Patent EP1572962.
JD430595 - Sequence 411619 from Patent EP1572962.
JD430596 - Sequence 411620 from Patent EP1572962.
JD421970 - Sequence 402994 from Patent EP1572962.
JD048067 - Sequence 29091 from Patent EP1572962.
JD325558 - Sequence 306582 from Patent EP1572962.
JD286168 - Sequence 267192 from Patent EP1572962.
JD427937 - Sequence 408961 from Patent EP1572962.
JD410499 - Sequence 391523 from Patent EP1572962.
JD219396 - Sequence 200420 from Patent EP1572962.
JD176848 - Sequence 157872 from Patent EP1572962.
JD334351 - Sequence 315375 from Patent EP1572962.
JD107496 - Sequence 88520 from Patent EP1572962.
JD078214 - Sequence 59238 from Patent EP1572962.
JD270461 - Sequence 251485 from Patent EP1572962.
JD504413 - Sequence 485437 from Patent EP1572962.
JD207526 - Sequence 188550 from Patent EP1572962.
JD511847 - Sequence 492871 from Patent EP1572962.
JD321987 - Sequence 303011 from Patent EP1572962.
JD095290 - Sequence 76314 from Patent EP1572962.
JD271415 - Sequence 252439 from Patent EP1572962.
JD423483 - Sequence 404507 from Patent EP1572962.
JD200624 - Sequence 181648 from Patent EP1572962.
JD523656 - Sequence 504680 from Patent EP1572962.
JD351795 - Sequence 332819 from Patent EP1572962.
JD448381 - Sequence 429405 from Patent EP1572962.
JD541216 - Sequence 522240 from Patent EP1572962.
JD300624 - Sequence 281648 from Patent EP1572962.
JD494287 - Sequence 475311 from Patent EP1572962.
JD114579 - Sequence 95603 from Patent EP1572962.
JD374350 - Sequence 355374 from Patent EP1572962.
JD506294 - Sequence 487318 from Patent EP1572962.
JD356586 - Sequence 337610 from Patent EP1572962.
JD330333 - Sequence 311357 from Patent EP1572962.
JD488519 - Sequence 469543 from Patent EP1572962.
JD205337 - Sequence 186361 from Patent EP1572962.
JD243647 - Sequence 224671 from Patent EP1572962.
JD176295 - Sequence 157319 from Patent EP1572962.
JD554290 - Sequence 535314 from Patent EP1572962.
JD352390 - Sequence 333414 from Patent EP1572962.
JD048099 - Sequence 29123 from Patent EP1572962.
JD363206 - Sequence 344230 from Patent EP1572962.
JD450509 - Sequence 431533 from Patent EP1572962.
JD534090 - Sequence 515114 from Patent EP1572962.
JD229336 - Sequence 210360 from Patent EP1572962.
JD404166 - Sequence 385190 from Patent EP1572962.
JD127390 - Sequence 108414 from Patent EP1572962.
JD457911 - Sequence 438935 from Patent EP1572962.
JD334358 - Sequence 315382 from Patent EP1572962.
JD107507 - Sequence 88531 from Patent EP1572962.
JD456221 - Sequence 437245 from Patent EP1572962.
JD507401 - Sequence 488425 from Patent EP1572962.
JD252515 - Sequence 233539 from Patent EP1572962.
JD107730 - Sequence 88754 from Patent EP1572962.
JD480171 - Sequence 461195 from Patent EP1572962.
JD541340 - Sequence 522364 from Patent EP1572962.
JD283757 - Sequence 264781 from Patent EP1572962.
JD427736 - Sequence 408760 from Patent EP1572962.
JD467445 - Sequence 448469 from Patent EP1572962.
JD141030 - Sequence 122054 from Patent EP1572962.
JD045007 - Sequence 26031 from Patent EP1572962.
JD203530 - Sequence 184554 from Patent EP1572962.
JD498145 - Sequence 479169 from Patent EP1572962.
JD226214 - Sequence 207238 from Patent EP1572962.
JD262922 - Sequence 243946 from Patent EP1572962.
JD058724 - Sequence 39748 from Patent EP1572962.
JD370754 - Sequence 351778 from Patent EP1572962.
JD339808 - Sequence 320832 from Patent EP1572962.
BC068464 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:87065 IMAGE:4826114), complete cds.
BC024216 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone IMAGE:4824157).
BC021994 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:24510 IMAGE:4096609), complete cds.
BC009582 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:14636 IMAGE:4082112), complete cds.
BC008477 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:14765 IMAGE:4290897), complete cds.
LF362339 - JP 2014500723-A/169842: Polycomb-Associated Non-Coding RNAs.
MA597916 - JP 2018138019-A/169842: Polycomb-Associated Non-Coding RNAs.
BC005299 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:12367 IMAGE:3838954), complete cds.
BC009578 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:14602 IMAGE:3961416), complete cds.
BC008475 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:14760 IMAGE:4284529), complete cds.
D00265 - Homo sapiens mRNA for cytochrome c, partial cds.
BC009602 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:14694 IMAGE:4134675), complete cds.
BC016006 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:27280 IMAGE:4656402), complete cds.
BC071761 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:88380 IMAGE:4656503), complete cds.
BC070346 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:88352 IMAGE:3826017), complete cds.
BC009607 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:14763 IMAGE:4287362), complete cds.
BC014359 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:24234 IMAGE:3930323), complete cds.
BC014361 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:24243 IMAGE:3931721), complete cds.
BC070156 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:88136 IMAGE:6451982), complete cds.
BC009579 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:14603 IMAGE:4045034), complete cds.
BC009587 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:14650 IMAGE:4096763), complete cds.
LF362340 - JP 2014500723-A/169843: Polycomb-Associated Non-Coding RNAs.
MA597917 - JP 2018138019-A/169843: Polycomb-Associated Non-Coding RNAs.
JD233896 - Sequence 214920 from Patent EP1572962.
JD507749 - Sequence 488773 from Patent EP1572962.
JD369416 - Sequence 350440 from Patent EP1572962.
BC022330 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:22759 IMAGE:4280695), complete cds.
BC015130 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:24248 IMAGE:3932265), complete cds.
BC067222 - Homo sapiens cytochrome c, somatic, mRNA (cDNA clone MGC:72005 IMAGE:3685258), complete cds.
JD263598 - Sequence 244622 from Patent EP1572962.
JD300901 - Sequence 281925 from Patent EP1572962.
JD241296 - Sequence 222320 from Patent EP1572962.
JD499360 - Sequence 480384 from Patent EP1572962.
JD409707 - Sequence 390731 from Patent EP1572962.
JD113152 - Sequence 94176 from Patent EP1572962.
JD357050 - Sequence 338074 from Patent EP1572962.
LF362342 - JP 2014500723-A/169845: Polycomb-Associated Non-Coding RNAs.
MA597919 - JP 2018138019-A/169845: Polycomb-Associated Non-Coding RNAs.
JD410955 - Sequence 391979 from Patent EP1572962.
CR542175 - Homo sapiens full open reading frame cDNA clone RZPDo834B1024D for gene CYCS, cytochrome c, somatic; complete cds, incl. stopcodon.
AK311836 - Homo sapiens cDNA, FLJ92098, Homo sapiens cytochrome c (HCS), mRNA.
DQ893038 - Synthetic construct clone IMAGE:100005668; FLH192890.01X; RZPDo839A0678D cytochrome c, somatic (CYCS) gene, encodes complete protein.
BT006946 - Homo sapiens cytochrome c, somatic mRNA, complete cds.
KJ894012 - Synthetic construct Homo sapiens clone ccsbBroadEn_03406 CYCS gene, encodes complete protein.
KJ898971 - Synthetic construct Homo sapiens clone ccsbBroadEn_08365 CYCS gene, encodes complete protein.
KR710178 - Synthetic construct Homo sapiens clone CCSBHm_00010208 CYCS (CYCS) mRNA, encodes complete protein.
DQ896279 - Synthetic construct Homo sapiens clone IMAGE:100010739; FLH192886.01L; RZPDo839A0668D cytochrome c, somatic (CYCS) gene, encodes complete protein.
AB489158 - Synthetic construct DNA, clone: pF1KB3400, Homo sapiens CYCS gene for cytochrome c, somatic, without stop codon, in Flexi system.
AM393213 - Synthetic construct Homo sapiens clone IMAGE:100001942 for hypothetical protein (CYCS gene).
AM393423 - Synthetic construct Homo sapiens clone IMAGE:100001911 for hypothetical protein (CYCS gene).
LF362343 - JP 2014500723-A/169846: Polycomb-Associated Non-Coding RNAs.
MA597920 - JP 2018138019-A/169846: Polycomb-Associated Non-Coding RNAs.
LF362344 - JP 2014500723-A/169847: Polycomb-Associated Non-Coding RNAs.
MA597921 - JP 2018138019-A/169847: Polycomb-Associated Non-Coding RNAs.
JD289248 - Sequence 270272 from Patent EP1572962.

-  Biochemical and Signaling Pathways
  KEGG - Kyoto Encyclopedia of Genes and Genomes
hsa04115 - p53 signaling pathway
hsa04210 - Apoptosis
hsa05010 - Alzheimer's disease
hsa05012 - Parkinson's disease
hsa05014 - Amyotrophic lateral sclerosis (ALS)
hsa05016 - Huntington's disease
hsa05200 - Pathways in cancer
hsa05210 - Colorectal cancer
hsa05222 - Small cell lung cancer
hsa05416 - Viral myocarditis

Reactome (by CSHL, EBI, and GO)

Protein P99999 (Reactome details) participates in the following event(s):

R-HSA-114254 Cytochrome C Binds to Apaf-1
R-HSA-114284 Release of Cytochrome c from mitochondria
R-HSA-5688294 SIRT5 deacetylates Cytochrome C
R-HSA-114256 Cytochrome C:Apaf-1 binds Procaspase-9
R-HSA-164651 Electron transfer from ubiquinol to cytochrome c of complex III
R-HSA-3341294 Superoxide reduces cytochrome c
R-HSA-163214 Electron transfer from reduced cytochrome c to molecular oxygen
R-HSA-114259 Cleavage of Procaspase-9 to Caspase-9
R-HSA-114252 Cleavage of Procaspase-3 by the apoptosome
R-HSA-114261 Cleavage of Procaspase-7 by the apoptosome
R-HSA-111458 Formation of apoptosome
R-HSA-111457 Release of apoptotic factors from the mitochondria
R-HSA-2151201 Transcriptional activation of mitochondrial biogenesis
R-HSA-111461 Cytochrome c-mediated apoptotic response
R-HSA-109606 Intrinsic Pathway for Apoptosis
R-HSA-1592230 Mitochondrial biogenesis
R-HSA-611105 Respiratory electron transport
R-HSA-3299685 Detoxification of Reactive Oxygen Species
R-HSA-5628897 TP53 Regulates Metabolic Genes
R-HSA-111471 Apoptotic factor-mediated response
R-HSA-109581 Apoptosis
R-HSA-1852241 Organelle biogenesis and maintenance
R-HSA-163200 Respiratory electron transport, ATP synthesis by chemiosmotic coupling, and heat production by uncoupling proteins.
R-HSA-2262752 Cellular responses to stress
R-HSA-3700989 Transcriptional Regulation by TP53
R-HSA-111459 Activation of caspases through apoptosome-mediated cleavage
R-HSA-5357801 Programmed Cell Death
R-HSA-1428517 The citric acid (TCA) cycle and respiratory electron transport
R-HSA-8953897 Cellular responses to external stimuli
R-HSA-212436 Generic Transcription Pathway
R-HSA-1430728 Metabolism
R-HSA-73857 RNA Polymerase II Transcription
R-HSA-74160 Gene expression (Transcription)

-  Other Names for This Gene
  Alternate Gene Symbols: A4D166, B2R4I1, CYC, CYC_HUMAN, NM_018947, P00001, P99999, Q6NUR2, Q6NX69, Q96BV4, uc003sxl.1, uc003sxl.2, uc003sxl.3, uc003sxl.4
UCSC ID: uc003sxl.4
RefSeq Accession: NM_018947
Protein: P99999 (aka CYC_HUMAN)
CCDS: CCDS5393.1

-  Methods, Credits, and Use Restrictions
  Click here for details on how this gene model was made and data restrictions if any.