Cyclin T2 Explained

Cyclin-T2 is a protein that in humans is encoded by the CCNT2 gene.^{[1] [2] [3]}

Function

The protein encoded by this gene belongs to the highly conserved cyclin family, whose members are characterized by a dramatic periodicity in protein abundance through the cell cycle. Cyclins function as regulators of CDK kinases. Different cyclins exhibit distinct expression and degradation patterns which contribute to the temporal coordination of each mitotic event. This cyclin and its kinase partner CDK9 were found to be subunits of the transcription elongation factor p-TEFb. The p-TEFb complex containing this cyclin was reported to interact with, and act as a negative regulator of human immunodeficiency virus type 1 (HIV-1) Tat protein. Two alternatively spliced transcript variants, which encode distinct isoforms, have been described.^[3]

Interactions

Cyclin T2 has been shown to interact with CDK9 and Retinoblastoma protein.^[4]

Further reading

• Wolff A . [Problem of occupational disability hazards] . Lebensversicher Med . 28 . 3 . 76–7 . 1976 . 9544 .
• Wimmer J, Fujinaga K, Taube R, Cujec TP, Zhu Y, Peng J, Price DH, Peterlin BM . Interactions between Tat and TAR and human immunodeficiency virus replication are facilitated by human cyclin T1 but not cyclins T2a or T2b . Virology . 255 . 1 . 182–9 . 1999 . 10049833 . 10.1006/viro.1998.9589 . free .
• Richard Gaynor. Kwak YT, Ivanov D, Guo J, Nee E, Gaynor RB . Role of the human and murine cyclin T proteins in regulating HIV-1 tat-activation . J. Mol. Biol. . 288 . 1 . 57–69 . 1999 . 10329126 . 10.1006/jmbi.1999.2664 .
• Bieniasz PD, Grdina TA, Bogerd HP, Cullen BR . Analysis of the effect of natural sequence variation in Tat and in cyclin T on the formation and RNA binding properties of Tat-cyclin T complexes . J. Virol. . 73 . 7 . 5777–86 . 1999 . 10364329 . 112638 . 10.1128/JVI.73.7.5777-5786.1999.
• Herrmann CH, Mancini MA . The Cdk9 and cyclin T subunits of TAK/P-TEFb localize to splicing factor-rich nuclear speckle regions . J. Cell Sci. . 114 . Pt 8 . 1491–503 . 2001 . 10.1242/jcs.114.8.1491 . 11282025 .
• Nguyen VT, Kiss T, Michels AA, Bensaude O . 7SK small nuclear RNA binds to and inhibits the activity of CDK9/cyclin T complexes . Nature . 414 . 6861 . 322–5 . 2001 . 11713533 . 10.1038/35104581 . 2001Natur.414..322N . 4341651 .
• Tolstonog GV, Mothes E, Shoeman RL, Traub P . Isolation of SDS-stable complexes of the intermediate filament protein vimentin with repetitive, mobile, nuclear matrix attachment region, and mitochondrial DNA sequence elements from cultured mouse and human fibroblasts . DNA Cell Biol. . 20 . 9 . 531–54 . 2001 . 11747605 . 10.1089/104454901317094954 .
• Simone C, Bagella L, Bellan C, Giordano A . Physical interaction between pRb and cdk9/cyclinT2 complex . Oncogene . 21 . 26 . 4158–65 . 2002 . 12037672 . 10.1038/sj.onc.1205511 . 44657967 .
• Michels AA, Nguyen VT, Fraldi A, Labas V, Edwards M, Bonnet F, Lania L, Bensaude O . MAQ1 and 7SK RNA interact with CDK9/cyclin T complexes in a transcription-dependent manner . Mol. Cell. Biol. . 23 . 14 . 4859–69 . 2003 . 12832472 . 162212 . 10.1128/MCB.23.14.4859-4869.2003 .
• Beausoleil SA, Jedrychowski M, Schwartz D, Elias JE, Villén J, Li J, Cohn MA, Cantley LC, Gygi SP . Large-scale characterization of HeLa cell nuclear phosphoproteins . Proc. Natl. Acad. Sci. U.S.A. . 101 . 33 . 12130–5 . 2004 . 15302935 . 514446 . 10.1073/pnas.0404720101 . 2004PNAS..10112130B . free .
• Kurosu T, Zhang F, Peterlin BM . Transcriptional activity and substrate recognition of cyclin T2 from P-TEFb . Gene . 343 . 1 . 173–9 . 2004 . 15563843 . 10.1016/j.gene.2004.08.027 .
• Jang MK, Mochizuki K, Zhou M, Jeong HS, Brady JN, Ozato K . The bromodomain protein Brd4 is a positive regulatory component of P-TEFb and stimulates RNA polymerase II-dependent transcription . Mol. Cell . 19 . 4 . 523–34 . 2005 . 16109376 . 10.1016/j.molcel.2005.06.027 . free .
• Cottone G, Baldi A, Palescandolo E, Manente L, Penta R, Paggi MG, De Luca A . Pkn is a novel partner of cyclin T2a in muscle differentiation . J. Cell. Physiol. . 207 . 1 . 232–7 . 2006 . 16331689 . 10.1002/jcp.20566 . 7382847 .
• Simone C, Giordano A . Abrogation of signal-dependent activation of the cdk9/cyclin T2a complex in human RD rhabdomyosarcoma cells . Cell Death Differ. . 14 . 1 . 192–5 . 2007 . 16841087 . 10.1038/sj.cdd.4402008 . free .
• Fu J, Yoon HG, Qin J, Wong J . Regulation of P-TEFb elongation complex activity by CDK9 acetylation . Mol. Cell. Biol. . 27 . 13 . 4641–51 . 2007 . 17452463 . 1951478 . 10.1128/MCB.00857-06 .

Notes and References

1. Peng J, Zhu Y, Milton JT, Price DH . Identification of multiple cyclin subunits of human P-TEFb . Genes Dev. . 12 . 5 . 755–62 . Apr 1998 . 9499409 . 316581 . 10.1101/gad.12.5.755 .
2. Napolitano G, Licciardo P, Gallo P, Majello B, Giordano A, Lania L . The CDK9-associated cyclins T1 and T2 exert opposite effects on HIV-1 Tat activity . AIDS . 13 . 12 . 1453–9 . Nov 1999 . 10465067 . 10.1097/00002030-199908200-00003 . free .
3. Web site: Entrez Gene: CCNT2 cyclin T2.
4. Simone C, Bagella L, Bellan C, Giordano A . Physical interaction between pRb and cdk9/cyclinT2 complex . Oncogene . 21 . 26 . 4158–65 . Jun 2002 . 12037672 . 10.1038/sj.onc.1205511 . 44657967 .