The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)



Gene Review

CCNK  -  cyclin K

Homo sapiens

Synonyms: CPR4, Cyclin-K
Welcome! If you are familiar with the subject of this article, you can contribute to this open access knowledge base by deleting incorrect information, restructuring or completely rewriting any text. Read more.

Disease relevance of CCNK

  • Using cDNA microarray technology, we found that cyclin K mRNA was dramatically increased in U373MG, a glioblastoma cell line deficient in wild-type p53, in the presence of exogenous p53 [1].
  • Altogether, these results suggest that KSHV is able to override growth suppressive effects through multiple mechanisms, and they further indicate that cyclin K plays an important role in the oncogenic activity of these viruses [2].
  • The primers CPL1 and CPR4 were tested for their ability to amplify DNA from 30 strains of C. neoformans and 27 specimens of cerebrospinal fluid (CSF) from patients with cryptococcal meningitis [3].

High impact information on CCNK


Biological context of CCNK

  • A prominent feature of cyclin K is an additional helix (H4a) in the first cyclin box that obstructs the binding pocket for the cell-cycle inhibitor p27(Kip1) [6].
  • Cdk9 function depends on its kinase activity and also on its regulatory units: the T-family cyclins and cyclin K. Recently, several studies confirmed the role of cdk9 in different cellular processes such as signal transduction, basal transcription, HIV-Tat- and MyoD-mediated transcription and differentiation [7].
  • We identified two other genes whose levels were decreased and these are known to be involved in the regulation of cell proliferation (cyclin K and p-100) [8].

Physical interactions of CCNK


Regulatory relationships of CCNK


Other interactions of CCNK

  • The cyclin K fold comprises two typical cyclin boxes with two short helices preceding the N-terminal box [6].
  • Biochemical analyses indicate that cyclin K functions as a regulatory subunit of CDK9 [9].
  • Cyclin K as a direct transcriptional target of the p53 tumor suppressor [1].
  • Cyclin K, a newly recognized member of the "transcription" cyclin family, may play a dual role by regulating CDK and transcription [1].

Analytical, diagnostic and therapeutic context of CCNK

  • In this study, we show that cyclin K overrides growth suppressive signals through signal transducer and activator of transcription 3 (STAT3) inactivation [2].


  1. Cyclin K as a direct transcriptional target of the p53 tumor suppressor. Mori, T., Anazawa, Y., Matsui, K., Fukuda, S., Nakamura, Y., Arakawa, H. Neoplasia (2002) [Pubmed]
  2. Kaposi sarcoma-associated viral cyclin K overrides cell growth inhibition mediated by oncostatin M through STAT3 inhibition. Lundquist, A., Barré, B., Bienvenu, F., Hermann, J., Avril, S., Coqueret, O. Blood (2003) [Pubmed]
  3. Assessment of a PCR technique for the detection and identification of Cryptococcus neoformans. Prariyachatigul, C., Chaiprasert, A., Meevootisom, V., Pattanakitsakul, S. J. Med. Vet. Mycol. (1996) [Pubmed]
  4. Human cyclin K, a novel RNA polymerase II-associated cyclin possessing both carboxy-terminal domain kinase and Cdk-activating kinase activity. Edwards, M.C., Wong, C., Elledge, S.J. Mol. Cell. Biol. (1998) [Pubmed]
  5. P-TEFb containing cyclin K and Cdk9 can activate transcription via RNA. Lin, X., Taube, R., Fujinaga, K., Peterlin, B.M. J. Biol. Chem. (2002) [Pubmed]
  6. Crystal Structure of Human Cyclin K, a Positive Regulator of Cyclin-dependent Kinase 9. Baek, K., Brown, R.S., Birrane, G., Ladias, J.A. J. Mol. Biol. (2007) [Pubmed]
  7. New insight in cdk9 function: from Tat to MyoD. Simone, C., Giordano, A. Front. Biosci. (2001) [Pubmed]
  8. Detection of differentially expressed genes in human colon carcinoma cells treated with a selective COX-2 inhibitor. Zhang, Z., DuBois, R.N. Oncogene (2001) [Pubmed]
  9. Cyclin K functions as a CDK9 regulatory subunit and participates in RNA polymerase II transcription. Fu, T.J., Peng, J., Lee, G., Price, D.H., Flores, O. J. Biol. Chem. (1999) [Pubmed]
WikiGenes - Universities