p21(Cip1/Waf1) inhibits cell-cycle progression by binding to G1 cyclin/CDK complexes and proliferating cell nuclear antigen (PCNA) through its N- and C-terminal domains, respectively. Here, we report a novel p21(Cip1/Waf1)-interacting protein, Ciz1 (for Cip1 interacting zinc finger protein), which contains polyglutamine repeats and glutamine-rich region in the N-terminus as well as three zinc-finger motifs and one MH3 (matrin 3-homologous domain 3) in the C-terminal region, Ciz1 bound to the N-terminal, the CDK2-interacting part of p21(Cip1/Waf1), and the interaction was disrupted by the overexpression of CDK2. A region of about 150 amino acids containing the first zinc-finger motif in Ciz1 was the binding site for p21(Cip/Waf1). When Ciz1 and p21(Cip/Waf1) were individually overexpressed in U2-OS cells, they mostly localized in the nucleus. However, coexpression of Ciz1 induced cytoplasmic distribution of p21(Cip1/Waf1). These data indicate that Ciz1 is a unique nuclear protein that regulates the cellular localization of p21(Cip/Waf1).
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|Publication status||Published - 1999 Oct 22|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology