Seroatlas · Human Serome Atlas

ORC3

Origin recognition complex subunit 3

Also known as: IMAGE50150, LATHEO, ORC3_HUMAN, ORC3L

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
Q9UBD5
Gene
ORC3
Ensembl
ENSG00000135336
Chromosome
6
Canonical length
711 aa
Protein class
Predicted intracellular proteins, Predicted membrane proteins
Subcellular location
Nucleoplasm

OverviewNCBI Gene

The origin recognition complex (ORC) is a highly conserved six subunits protein complex essential for the initiation of the DNA replication in eukaryotic cells. Studies in yeast demonstrated that ORC binds specifically to origins of replication and serves as a platform for the assembly of additional initiation factors such as Cdc6 and Mcm proteins. The protein encoded by this gene is a subunit of the ORC complex. Studies of a similar gene in Drosophila suggested a possible role of this protein in neuronal proliferation and olfactory memory. Alternatively spliced transcript variants encoding distinct isoforms have been reported for this gene. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

711 residues, UniProt reviewed canonical sequence.

>Q9UBD5|ORC3
     1  MATSSMSKGC FVFKPNSKKR KISLPIEDYF NKGKNEPEDS KLRFETYQLI WQQMKSENER
    61  LQEELNKNLF DNLIEFLQKS HSGFQKNSRD LGGQIKLREI PTAALVLGVN VTDHDLTFGS
   121  LTEALQNNVT PYVVSLQAKD CPDMKHFLQK LISQLMDCCV DIKSKEEESV HVTQRKTHYS
   181  MDSLSSWYMT VTQKTDPKML SKKRTTSSQW QSPPVVVILK DMESFATKVL QDFIIISSQH
   241  LHEFPLILIF GIATSPIIIH RLLPHAVSSL LCIELFQSLS CKEHLTTVLD KLLLTTQFPF
   301  KINEKVLQVL TNIFLYHDFS VQNFIKGLQL SLLEHFYSQP LSVLCCNLPE AKRRINFLSN
   361  NQCENIRRLP SFRRYVEKQA SEKQVALLTN ERYLKEETQL LLENLHVYHM NYFLVLRCLH
   421  KFTSSLPKYP LGRQIRELYC TCLEKNIWDS EEYASVLQLL RMLAKDELMT ILEKCFKVFK
   481  SYCENHLGST AKRIEEFLAQ FQSLDETKEE EDASGSQPKG LQKTDLYHLQ KSLLEMKELR
   541  RSKKQTKFEV LRENVVNFID CLVREYLLPP ETQPLHEVVY FSAAHALREH LNAAPRIALH
   601  TALNNPYYYL KNEALKSEEG CIPNIAPDIC IAYKLHLECS RLINLVDWSE AFATVVTAAE
   661  KMDANSATSE EMNEIIHARF IRAVSELELL GFIKPTKQKT DHVARLTWGG C

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against ORC3 can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Intracellular
Secreted
No
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.32
Highest tissue expression
31 nTPM

Expression across tissuesHPA

Tissue

  • retina: 31 nTPM
  • testis: 24 nTPM
  • skeletal muscle: 20 nTPM
  • thymus: 19 nTPM
  • tongue: 19 nTPM
  • heart muscle: 19 nTPM

Single-cell type

  • myonuclei: 123 nCPM
  • corticotrophs: 119 nCPM
  • lactotrophs: 110 nCPM
  • somatotrophs: 108 nCPM
  • late primary spermatocytes: 107 nCPM
  • thyrotrophs: 101 nCPM

Immune cell

  • non-classical monocyte: 23 nTPM
  • basophil: 23 nTPM
  • naive CD4 T-cell: 22 nTPM
  • NK-cell: 20 nTPM
  • T-reg: 19 nTPM
  • MAIT T-cell: 19 nTPM

Brain region

  • cerebellum: 34 nTPM
  • white matter: 30 nTPM
  • spinal cord: 26 nTPM
  • medulla oblongata: 26 nTPM
  • pons: 25 nTPM
  • cerebral cortex: 25 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about ORC3.

Disease | GeneticClinVar

2 pathogenic / likely-pathogenic of 133 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

  • ORC3-related disorder

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
0.71
gnomAD pLI
0
gnomAD missense Z
0.52
DepMap mean gene effect
-0.47
DepMap dependency class
selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

  • Origin recognition complex, subunit 3
  • Origin recognition complex subunit 3, winged helix C-terminal
  • Origin recognition complex subunit 3, insertion domain
  • Origin recognition complex subunit 3, N-terminal
  • Origin recognition complex (ORC) subunit 3 N-terminus
  • Origin recognition complex winged helix C-terminal
  • Origin recognition complex subunit 3 insertion domain

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of ORC3 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads ORC3 as an antibody target. Whether an autoantibody or antibody against ORC3 could matter depends on whether native ORC3 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

ORC3 is annotated as predominantly intracellular. Intracellular proteins are common autoantibody markers, becoming visible to the immune system after cell injury or altered processing, but are usually markers of disease rather than direct drivers.

Annotation status

The present source text does not explicitly label ORC3 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/ORC3. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

© 2026 · Seroatlas, Discover Oregon LLC · Terms of use

Loading the interactive Seroatlas protein explorer...