Thiamin-dependent transactivation activity of PDC2 in Saccharomyces cerevisiae.
Yeast genes involved in thiamin pyrophosphate (TPP) synthesis are transcriptionally induced in response to thiamin starvation. In this system, three proteins (Thi2p, Thi3p, and Pdc2p) act as positive regulatory factors. Thi3p is a TPP-binding protein and upregulates THI genes expression when TPP is not bound. We found here that Pdc2p could transactivate gene expression and interact with Thi3p, both of which were enhanced by thiamin starvation. This enhancement of the transactivation activity was not observed in a thi3 strain. When the C-terminal region containing the deduced Thi3p-interacting domain was truncated, Pdc2p expressed striking transactivation activity in a Thi3p-independent fashion. We explored the hypothesis that Thi3p causes a conformational change in Pdc2p leading to full transactivation activity under favorable conditions.
Nosaka
Kazuto
K
Department of Chemistry, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kita-ku, Kyoto 603-8334, Japan. knosaka@koto.kpu-m.ac.jp
Onozuka
Mari
M
Konno
Hiroyuki
H
Akaji
Kenichi
K
D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D015966:Gene Expression Regulation, Fungal; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013831:Thiamine / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D020798:Two-Hybrid System Techniques
D002352:Carrier Proteins; C103820:PDC2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C535167:Thi3 protein, S cerevisiae; D014157:Transcription Factors; D013831:Thiamine