Seroatlas · Human Serome Atlas

CDK9

Cyclin-dependent kinase 9

Also known as: C-2k, CDC2L4, CDK9_HUMAN, PITALRE, TAK

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

Protein identityUniProt · HPA

UniProt accession
P50750
Gene
CDK9
Ensembl
ENSG00000136807
Chromosome
9
Canonical length
372 aa
Protein class
Disease related genes, Enzymes, Plasma proteins, Potential drug targets, Predicted intracellular proteins
Subcellular location
Nucleoplasm,Cytoplasmic bodies

OverviewNCBI Gene

The protein encoded by this gene is a member of the cyclin-dependent protein kinase (CDK) family. CDK family members are highly similar to the gene products of S. cerevisiae cdc28, and S. pombe cdc2, and known as important cell cycle regulators. This kinase was found to be a component of the multiprotein complex TAK/P-TEFb, which is an elongation factor for RNA polymerase II-directed transcription and functions by phosphorylating the C-terminal domain of the largest subunit of RNA polymerase II. This protein forms a complex with and is regulated by its regulatory subunit cyclin T or cyclin K. HIV-1 Tat protein was found to interact with this protein and cyclin T, which suggested a possible involvement of this protein in AIDS. [provided by RefSeq, Jul 2008]

Canonical amino-acid sequenceUniProt

372 residues, UniProt reviewed canonical sequence.

>P50750|CDK9
     1  MAKQYDSVEC PFCDEVSKYE KLAKIGQGTF GEVFKARHRK TGQKVALKKV LMENEKEGFP
    61  ITALREIKIL QLLKHENVVN LIEICRTKAS PYNRCKGSIY LVFDFCEHDL AGLLSNVLVK
   121  FTLSEIKRVM QMLLNGLYYI HRNKILHRDM KAANVLITRD GVLKLADFGL ARAFSLAKNS
   181  QPNRYTNRVV TLWYRPPELL LGERDYGPPI DLWGAGCIMA EMWTRSPIMQ GNTEQHQLAL
   241  ISQLCGSITP EVWPNVDNYE LYEKLELVKG QKRKVKDRLK AYVRDPYALD LIDKLLVLDP
   301  AQRIDSDDAL NHDFFWSDPM PSDLKGMLST HLTSMFEYLA PPRRKGSQIT QQSTNQSRNP
   361  ATTNQTEFER VF

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CDK9 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)
0.3
Highest tissue expression
85 nTPM

Expression across tissuesHPA

Tissue

  • ovary: 85 nTPM
  • cerebellum: 67 nTPM
  • pituitary gland: 65 nTPM
  • spleen: 63 nTPM
  • fallopian tube: 62 nTPM
  • liver: 62 nTPM

Single-cell type

  • bergmann glia: 66 nCPM
  • syncytiotrophoblasts: 64 nCPM
  • ependymal cells: 63 nCPM
  • esophageal apical cells: 55 nCPM
  • podocytes: 50 nCPM
  • astrocytes: 49 nCPM

Immune cell

  • NK-cell: 23 nTPM
  • gdT-cell: 10 nTPM
  • MAIT T-cell: 10 nTPM
  • plasmacytoid DC: 10 nTPM
  • memory CD8 T-cell: 8.3 nTPM
  • naive CD8 T-cell: 7.9 nTPM

Brain region

  • cerebral cortex: 73 nTPM
  • hippocampal formation: 72 nTPM
  • midbrain: 60 nTPM
  • medulla oblongata: 60 nTPM
  • white matter: 59 nTPM
  • amygdala: 59 nTPM

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)
0.95
gnomAD pLI
0
gnomAD missense Z
2.14
DepMap mean gene effect
-1.45
DepMap dependency class
pan

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 6% 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

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of CDK9 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 CDK9 as an antibody target. Whether an autoantibody or antibody against CDK9 could matter depends on whether native CDK9 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CDK9 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 CDK9 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CDK9. 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).

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