Identification of SAP155 as the Target of GEX1A (Herboxidiene), an Antitumor Natural Product

Autor: Tetsuo Yoshida, Minoru Yoshida, Makoto Hasegawa, Koshiki Mino, Ryuzo Sasaki, Koichi Koseki, Tamio Mizukami, Kouji Kuzuya, Ayu Inoue, Tatsuki Kunoh, Tatsuhiro Miura, Sueharu Horinouchi, Se Won Ki
Rok vydání: 2011
Předmět:
Zdroj: ACS Chemical Biology. 6:229-233
ISSN: 1554-8937
1554-8929
Popis: GEX1A is a microbial product with antitumor activity. HeLa cells cultured with GEX1A accumulated p27(Kip) and its C-terminally truncated form p27*. GEX1A inhibited the pre-mRNA splicing of p27, producing p27* from the unspliced mRNA containing the first intron. p27* lacked the site required for E3 ligase-mediated proteolysis of p27, leading to its accumulation in GEX1A-treated cells. The accumulated p27* was able to bind to and inhibit the cyclin E-Cdk2 complex that causes E3 ligase-mediated degradation of p27, which probably triggers the accumulation of p27. By using a series of photoaffinity-labeling derivatives of GEX1A, we found that GEX1A targeted SAP155 protein, a subunit of SF3b responsible for pre-mRNA splicing. The linker length between the GEX1A pharmacophore and the photoreactive group was critical for detection of the GEX1A-binding protein. GEX1A serves as a novel splicing inhibitor that specifically impairs the SF3b function by binding to SAP155.
Databáze: OpenAIRE