Cyclin-T1 (IPR028863)

Short name: CCNT1

Overlapping homologous superfamilies


Family relationships



Cyclins are eukaryotic proteins that play an active role in controlling nuclear cell division cycles [PMID: 12910258], and regulate cyclin dependent kinases (CDKs). This entry represents cyclin-T1 from vertebrates.

Cyclin-T associates with CDK9. Both cyclin-T and CDK9 are subunits of the positive-transcription elongation factor (P-TEFb), which facilitates transcription elongation by phosphorylating the carboxy-terminal domain (CTD) of the largest subunit of pol II [PMID: 10574912]. In humans, there are three T-type cyclins: cyclins T1, T2a and T2b. Cyclins T2a and T2b are splice variants of a primary transcript [PMID: 15276198]. Each of the T-type cyclin/CDK9 complexes can phosphorylate the C-terminal domain of the large subunit of RNA polymerase II. However, only human cyclin T1/CDK9 complexes can bind HIV Tat and promote RNA Pol II activation, allowing transcription of viral genes [PMID: 15276198, PMID: 16109377, PMID: 18655042, PMID: 23110726].

GO terms

Biological Process

GO:0006351 transcription, DNA-templated

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.