The distinct methods by which manganese and iron regulate the Nramp transporters in yeast.-猫眼课题宝

锰和铁调节酵母中 Nramp 转运蛋白的不同方法。

DOI：

10.1042/0264-6021:3620119

发表时间：

2002

期刊：

The Biochemical journal

影响因子：

通讯作者：

中科院分区：

文献类型：

作者：

Portnoy,MatthewE;Jensen,LaranT;Culotta,ValeriaCizewski

The bakers yeastSaccharomyces cerevisiaeexpresses three Smf metal transport proteins that are differentially regulated by metal ions. Smf1p and Smf2p are regulated at the post-translational level by manganese, whereas Smf3p is regulated by iron through a mechanism that, up until now, was unknown. Through promoter and protein-domain swapping experiments, we now demonstrate that the manganese regulation of Smf1p involves an internal protein-coding region that is separate from the N-terminal domain of this transporter. By comparison, iron regulation of Smf3p involves the upstream non-coding region of the gene. UsingSMF3—lacZreporter constructs, we identified two distinct regions of theSMF3promoter that contribute to iron regulation: (1) approx. nt −435 to −350 that contain dual consensus recognition sites for the Aft1 iron transcription factor; and (2) nt −348 to −247 that do not contain obvious Aft1 binding sites. The −348 to −247 region by itself can confer strong iron regulation to the heterologousCYC1core promoter, and therefore harbours a putative upstream activating sequence for iron. Iron regulation ofSMF3was dramatically reduced, but not completely eliminated, in strains lacking both theAFT1andAFT2iron regulatory factors. Together with the promoter mapping studies, these results suggest that both Aft-dependent and Aft-independent pathways may contribute to iron regulation ofSMF3.