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Cyclin T: Three forms for different roles in physiological and pathological functions
Author(s) -
De Luca Antonio,
De Falco Maria,
Baldi Alfonso,
Paggi Marco G.
Publication year - 2003
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.10196
Subject(s) - cyclin a , cyclin d , cyclin a2 , cyclin dependent kinase , cyclin , cyclin dependent kinase complex , cyclin e , cyclin b , microbiology and biotechnology , biology , biochemistry , cell cycle , gene
Cyclins are members of family of proteins involved in the cell cycle regulation. They are regulatory subunits of complexes with proteins called cyclin‐dependent kinases (CDKs). There are three forms of cyclin T: cyclin T1, cyclin T2a, and T2b. All cyclin T contain an N‐terminal “cyclin homology box,” the most conserved region among different members of the cyclin family that serves to bind CDK9. In addition to the N‐terminal cyclin domain, cyclin T contains a putative coiled‐coil motif, a His‐rich motif, and a C‐terminal PEST sequence. The CDK9/cyclin T complex is able to activate gene expression in a catalytic‐dependent manner, phosphorylating the carboxy‐terminal domain (CTD) of RNA polymerase II. In addition, only cyclin T1 supports interactions between Tat and TAR. The interaction of Tat with cyclin T1 alters the conformation of Tat to enhance the affinity and specificity of the Tat:TAR interaction. On the other hand, CDK9/cyclin T2 complexes are involved in the regulation of terminal differentiation in muscle cells. © 2002 Wiley‐Liss, Inc.